[
{
"id": "authors:mqamw-11s39",
"collection": "authors",
"collection_id": "mqamw-11s39",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190117-174447349",
"type": "monograph",
"title": "Stability Theory for Cross-Hatching. Part II. An Experiment on Turbulent Boundary Layer over a Wavy Wall",
"author": [
{
"family_name": "Lees",
"given_name": "L.",
"clpid": "Lees-L"
},
{
"family_name": "Kubota",
"given_name": "T.",
"clpid": "Kubota-T"
},
{
"family_name": "Sigal",
"given_name": "A.",
"clpid": "Sigal-Asher"
},
{
"literal": "Space and Missile Systems Organization"
}
],
"abstract": "An experimental investigation of turbulent boundary layer flow over wavy surfaces was conducted at low speed. Two models with the ratio of the amplitude to the wave length a/\u03bb = 0.03 and wave lengths \u03bb = 6\" and 12\" were tested in an open-circuit wind tunnel. The free stream velocity was 15.4 m/sec, giving Reynolds number Re = 2.54 X 10^4 per inch. Boundary-layer thickness varied from \u03b4 = 1.5\" to \u03b4 = 4.1\" by means of boundary-layer trips of various height, in order to change the ratio \u03bb/\u03b4. The fol- lowing measurements were taken: wall pressure distribution, average velocity and turbulence level, wall stress distribution, static and total pressures, and shear stress distribution across the layer.\n\nWall pressure perturbation is much lower than predicted by uniform, inviscid theory and is slightly non-symmetric. Wall stress distribution has a peak with C_f/C_f_o = 1.2 upstream of the crest and a dip of C_f/C_f_o = 0.6 upstream of the trough.\n\nThe turbulence intensities and shear stress distributions near the wall show oscillatory modulation superimposed on the reference flat plate pro- files. The amplitude of the oscillations decays exponentially toward the edge of the layer, so that in the outer part of the layer the turbulence quantities are practically independent of the longitudinal position.",
"publisher": "California Institute of Technology",
"publication_date": "2019-01-18"
},
{
"id": "authors:1qg2w-fs610",
"collection": "authors",
"collection_id": "1qg2w-fs610",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190115-160036728",
"type": "monograph",
"title": "Stability Theory for Cross Hatching. Part I. Linear Stability Theory",
"author": [
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
},
{
"family_name": "Kubota",
"given_name": "Toshi",
"clpid": "Kubota-T"
},
{
"family_name": "Ko",
"given_name": "Denny R. S.",
"clpid": "Ko-D-R-S"
},
{
"literal": "Space and Missile Systems Organization"
}
],
"abstract": "A linear instability theory was developed which couples small perturbations in surface shape of a subliming surface and resulting perturbations in aerodynamic heat-transfer rates. Equations governing compressible turbulent boundary layers were linearized for small perturbations whose streamwise scale lengths are comparable with the undisturbed boundary layer thickness. For turbulent shear stress, the mixing-length approximation was employed, and the turbulent Prandtl number was assumed to be unity for turbulent heat flux. Heat conduction within the ablating solid was analyzed by linearizing the boundary condition for small amplitude. Sample computations were made for a teflon surface ablating under turbulent boundary layer at Mach 2. 6, and the results indicate that the small surface perturbations are unstable within certain regions in the wave number - wave angle space.",
"publisher": "California Institute of Technology",
"publication_date": "2019-01-16"
},
{
"id": "authors:qzcx3-9qt61",
"collection": "authors",
"collection_id": "qzcx3-9qt61",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160121-153353232",
"type": "monograph",
"title": "Smog: a report to the people of the South Coast Air Basin. Part I. The EQL Strategy - A Summary (including Figures 1-14). Part II. The EQL Strategy - Legislative and Administrative Action Required",
"author": [
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
},
{
"family_name": "Borrelli",
"given_name": "Peter",
"clpid": "Borrelli-P"
},
{
"family_name": "Easterling",
"given_name": "Mahlon",
"clpid": "Easterling-M"
},
{
"family_name": "Klein",
"given_name": "Burton H.",
"clpid": "Klein-B-H"
},
{
"family_name": "Pauker",
"given_name": "Guy",
"clpid": "Pauker-G"
},
{
"family_name": "Poppe",
"given_name": "Robert",
"clpid": "Poppe-R"
},
{
"family_name": "List",
"given_name": "E. John",
"clpid": "List-E-J"
}
],
"doi": "10.7907/qzcx3-9qt61",
"publisher": "California Institute of Technology",
"publication_date": "2018-03-29"
},
{
"id": "authors:thz0z-vee29",
"collection": "authors",
"collection_id": "thz0z-vee29",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151203-165813194",
"type": "monograph",
"title": "Inviscid Hypersonic Flow Over Blunt-Nosed Slender Bodies",
"author": [
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
}
],
"abstract": "At hypersonic speeds the drag/area of a blunt nose is much larger than the drag/area of a slender afterbody, and the energy contained in the flow field in a plane at right angles to the flight direction is nearly constant over a downstream distance many times greater than the characteristic nose dimension. The transverse flow field exhibits certain similarity properties directly analogous to the flow similarity behind an intense blast wave found by G. I. Taylor and S. C. Lin. Conditions for constant energy show that the shape of the bow shock wave R(x) not\ntoo close to the nose is given by R/d = K_1 (\u03b3)(d/c)^(1/2) for a body of revolution, and by R/d = K_0(\u03b3) (x/d)^(2/3) for a planar body, where d is nose diameter, or leading-edge thickness. A comparison with the experiments of Hammitt, Vas, and Bogdonoff on a flat plate with a blunt leading-edge at M_\u221e = 13 in helium shows that the shock wave shape is predicted very accurately by this analysis. The predicted surface pressure distribution is somewhat\nless satisfactory.\n\nEnergy considerations combined with a detailed study of the\nequations of motion show that flow similarity is also possible for a class of bodies of the form r_b ~ x^m, provided that m' \u2264 m \u2264 1, where m' = 3/4 for a planar body and m' = (3/2(\u03b3+1))/(3\u03b3 + 2) for a body of revolution. When m < m' the shock shape is not similar to the body shape, and except for the constant energy flows the entire\nflow field some distance from the nose must depend to some extent on the details of the nose geometry.\n\nBe again again utilizing energy and drag considerations one finds that at hypersonic speeds the inviscid surface pressures generated by a blunt nose are larger than the pressures produced by boundary layer growth on a flat surface over a distance from the nose of order \u2113, where\n\u2113/d \u2243 1/15 ((Re_d)/M_\u221e^2))^3 (Here Re_d is free-stream Reynolds number based on leading-edge thickness.)\nThus at M_\u221e = 15 the viscous interaction effects should be important for Re_d < 10^3, but somewhere in the range 1500 < Re_d < 2000 the inviscid effects must spread rapidly over the plate surface, and certainly for Re_d > 3000 the inviscid pressure field is dominant and determines\nthe boundary layer development, skin friction and heat transfer over the forward portion of the body. These rough estimates are in qualitative agreement with the experimental results of References 7 and 9.",
"publisher": "California Institute of Technology",
"publication_date": "2015-12-04"
},
{
"id": "authors:7adrv-phr25",
"collection": "authors",
"collection_id": "7adrv-phr25",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151201-133700798",
"type": "monograph",
"title": "Finite Disturbance Effect on the Stability of a Laminar Incompressible Wake Behind a Flat Plate",
"author": [
{
"family_name": "Ko",
"given_name": "Denny R. S.",
"clpid": "Ko-D-R-S"
},
{
"family_name": "Kubota",
"given_name": "Toshi",
"clpid": "Kubota-T"
},
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
}
],
"abstract": "An integral method is used to investigate the interaction\nbetween the stability of a single frequency finite amplitude disturbance with the non-parallel mean flow in a laminar, incompressible wake behind a flat plate. The mean flow is assumed to be characterized by a few shape parameters. The integrals involving the fluctuating\ncomponents are determined as functions of those shape parameters by solving the inviscid Rayleigh equation of the linear stability theory using the local mean flow. The variations of the amplitude of the fluctuation and the mean flow in the streamwise direction are then determined from solving the set of ordinary differential equations.\nThe effect of coupling between the mean flow and the fluctuation was found to be very important. The calculations show good agreement with the experimental data of Sato and Kuriki.",
"publisher": "California Institute of Technology",
"publication_date": "2015-12-03"
},
{
"id": "authors:njzvj-g4779",
"collection": "authors",
"collection_id": "njzvj-g4779",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151124-143821828",
"type": "monograph",
"title": "Some Remarks on Integral Moment Methods for Laminar Boundary Layers with Application to Separation and Reattachment",
"author": [
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
},
{
"family_name": "Reeves",
"given_name": "Barry L.",
"clpid": "Reeves-B-L"
}
],
"abstract": "It is well known that the K\u00e1rm\u00e1n-Pohlhausen integral method\nis a rather poor approximation for the analysis of laminar boundary layers in regions of adverse pressure gradient, particularly when separation occurs. Perhaps not so well known, however, is the fact that the K\u00e1rm\u00e1n-Pohlhausen method may be completely inadequate downstream of separation, between the separation and reattachment\npoints. When a flow disturbance, such as a forward facing step or incident shock wave, is of sufficient strength to cause extensive separation, the static pressure variation along the surface takes the general appearance shown in Figure 1. The region where the static pressure is virtually constant (plateau) gives rise to much of the\ndifficulty, since the K\u00e1rm\u00e1n-Pohlhausen method must produce an attached, Blasius type velocity profile whenever the pressure gradient vanishes. Hence the K\u00e1rm\u00e1n-Pohlhausen method must predict reattachment upstream of the plateau, whereas in reality it occurs downstream\nof the plateau. Apparently what is needed is an integral method which exhibits velocity profiles containing reverse-flow for vanishingly small adverse pressure gradients analogous to the \"lower branch\"\nsolutions of the Falkner-Skan equation, which were found by Stewartson. The purpose of the present report is to demonstrate that the method first proposed by Walz \nand modified by Tani does indeed produce\nvelocity profiles with reverse flow, even in the limit of constant pressure, and would, therefore, appear to be a very promising method for predicting the behavior of separated flows. Furthermore this method\neliminates the need for a certain amount of empiricism inherent in other existing methods, such as is required at the present time with the Crocco-Lees theory.",
"publisher": "California Institute of Technology",
"publication_date": "2015-11-24"
},
{
"id": "authors:xgm4e-w1v24",
"collection": "authors",
"collection_id": "xgm4e-w1v24",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151105-155638313",
"type": "monograph",
"title": "Kinetic Theory Description of Conductive Heat Transfer from a Fine Wire",
"author": [
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
},
{
"family_name": "Liu",
"given_name": "Chung-Yen",
"clpid": "Liu-Chung-Yen"
}
],
"abstract": "The Maxwell moment method utilizing the two-sided Maxwellian\ndistribution function is applied to the problem of conductive heat transfer between two concentric cylinders at rest. Analytical solutions are obtained for small temperature differences between the cylinders.\nThe predicted heat transfer agrees very well with experiments performed by Bomelburg, Sch\u00e4fer-Rating and Eucken. Comparison with results given by Grad's thirteen moment equations, and with those given by Fourier's \"law\" plus the Maxwell-Smoluchowski temperature-jump\nboundary condition shows that the two-sided character in the\ndistribution function is a crucial factor in problems involving surface curvature.",
"publisher": "California Institute of Technology",
"publication_date": "2015-11-06"
},
{
"id": "authors:e7be0-4zg83",
"collection": "authors",
"collection_id": "e7be0-4zg83",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151104-163525738",
"type": "monograph",
"title": "Kinetic Theory Description of Plane, Compressible Couette Flow",
"author": [
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
},
{
"family_name": "Liu",
"given_name": "Chung-Yen",
"clpid": "Liu-Chung-Yen"
}
],
"abstract": "By utilizing the two-stream Maxwellian in Maxwell's integral\nequations of transfer we are able to find a closed-form solution of the problem of compressible plane Couette flow over the whole range of gas density from free molecule flow to atmospheric. The ratio of shear\nstress to the product of ordinary viscosity and velocity gradient, which is unity for a Newtonian fluid, here depends also on the gas density, the\nplate temperatures and the plate spacing. For example, this ratio decreases rapidly with increasing plate Mach number when the plate temperatures are fixed. On the other hand, at a fixed Mach number based on the temperature of one plate, this ratio approaches unity as\nthe temperature of the other plate increases. Similar remarks can be made for the ratio of heat flux to the product of ordinary heat conduction\ncoefficient and temperature gradient.\n\nThe effect of gas density on the skin friction and heat transfer coefficients is described in terms of a single rarefaction parameter, which amounts to evaluating gas properties at a certain \"kinetic temperature\"\ndefined in terms of plate Mach number and plate temperature ratio. One interesting result is the effect of plate temperature on velocity \"slip\".\nIn the Navier-Stokes regime most of the gas follows the hot plate, because the gas viscosity is larger there. As the gas density decreases the situation is reversed, because the velocity slip is larger at the hot plate\nthan at the cold plate. In the limiting case of a highly rarefied gas most of the gas follows the cold plate.",
"publisher": "California Institute of Technology",
"publication_date": "2015-11-05"
},
{
"id": "authors:16bsm-49w92",
"collection": "authors",
"collection_id": "16bsm-49w92",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151102-150954032",
"type": "monograph",
"title": "A Kinetic Theory Description of Rarefied Gas Flows",
"author": [
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
}
],
"abstract": "An approach to the kinetic theory of gas flows is developed which starts with Maxwell's original integral equations of transfer, rather than with the Maxwell-Boltzmann equation for the velocity distribution function itself. In this procedure the Maxwell-Boltzmann equation is satisfied in\na certain average sense, rather than at every point. The advantage of this method is that relatively simple distribution functions are utilized which contain a small number of unknown functions to be determined by\napplying the conservation laws, plus several additional higher moments. For simplicity a \"two-stream Maxwellian\" is employed, which is a natural extension and generalization of Mott-Smith's function for a normal shock,\nbut differs from it in certain essential respects. As an illustration, the method is applied to linearized plane Couette flow and Rayleigh's problem. Reasonable results are obtained for macroscopic quantities such as mean\nvelocity and shear stress over the whole range of densities from free-molecule flow to the Navier-Stokes regime. This technique is now being applied to some typical non-linear rarefied gas flows.",
"publisher": "California Institute of Technology",
"publication_date": "2015-11-03"
},
{
"id": "authors:yge61-bnq32",
"collection": "authors",
"collection_id": "yge61-bnq32",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150604-152209034",
"type": "monograph",
"title": "Plane Couette Flow at Low Mach Number According to the Kinetic Theory of Gases",
"author": [
{
"family_name": "Yang",
"given_name": "Hsun-Tiao",
"clpid": "Yang-H-T"
},
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
}
],
"abstract": "The thirteen-moment approximation developed by H. Grad\nfor solving the Maxwell-Boltzmann equation is applied to the problem of the relative shearing motion between two infinite, parallel flat plates (plane Couette flow). In order to bring out the molecular effects as directly as possible the problem is linearized by requiring\nthat the Mach number is small compared with unity, and that the temperature difference between the two plates is small compared with ambient temperature. According to the linearized Grad equations the shear stress in this case is given by the usual Navier-Stokes relation for all values of the parameter Re/M, in agreement with R. A.\nMillikan's postulate. Also the linearized boundary conditions for this problem are identical with the Maxwell slip relations utilized by Millikan, so the same expressions for slip velocity and drag coefficient\nare obtained. An examination of the drag data obtained by Kuhlthau, Chiang, and Bowyer and Talbot in their rotating-cylinder experiments at low densities shows that the variation of 1/C_DM with Re/M is predicted reasonably well by this theory over a range of Mach numbers\nfrom 0.15 to 1.40, in spite of the fact that the theory is supposed to hold only for low Mach numbers.",
"publisher": "California Institute of Technology",
"publication_date": "2015-06-05"
},
{
"id": "authors:serfy-vn655",
"collection": "authors",
"collection_id": "serfy-vn655",
"cite_using_url": "https://resolver.caltech.edu/CaltechEQL:EQL-M-16",
"type": "monograph",
"title": "Emissions and air quality trends in the South Coast Air Basin",
"author": [
{
"family_name": "Trijonis",
"given_name": "John C.",
"clpid": "Trijonis-J-C"
},
{
"family_name": "Peng",
"given_name": "Ted K.",
"clpid": "Peng-T-K"
},
{
"family_name": "McRae",
"given_name": "Gregory J.",
"clpid": "McRae-G-J"
},
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
}
],
"abstract": "This paper documents the historical trends of pollutant emissions and ambient air quality for the South Coast Air Basin (SCAB) for the period 1965-1974. Emission trends for nitrogen oxides. reactive hydrocarbons, and carbon monoxide are developed. A detailed appendix describes the methodology and presents the latest test information -- in particular the contribution of evaporative emissions from light-duty vehicles. Basin-wide and county trends are presented to characterize the overall changes as well as the spatial distribution of emissions. Ambient concentrations of total nitrogen oxides (NO_x), nitrogen dioxide (NO_2), oxidant (OX), and carbon monoxide (CO) are compared to the emissions changes during the same period. Detailed analyses of air quality indices, including extreme levels, average values. and frequency of standard violation are presented for each pollutant. The final section of the paper discusses current and proposed control strategies and their impact on future air quality.",
"doi": "10.7907/Z9J67DWH",
"publisher": "California Institute of Technology",
"publication_date": "2009-12-14"
},
{
"id": "authors:hkx6g-vm495",
"collection": "authors",
"collection_id": "hkx6g-vm495",
"cite_using_url": "https://resolver.caltech.edu/CaltechEQL:EQL-M-4",
"type": "monograph",
"title": "State Power Plant Siting: a Sketch of the Main Features of a Possible Approach",
"author": [
{
"family_name": "Krier",
"given_name": "James E.",
"clpid": "Krier-J-E"
},
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
},
{
"family_name": "Dawes",
"given_name": "Daniel",
"clpid": "Dawes-D"
}
],
"abstract": "Work on various phases of power plant technology and siting has been underway within the Environmental Quality Laboratory (EQL) at the California Institute of Technology for some time. Of particular relevance to this memorandum, a good deal of effort has been devoted to institutional aspects of the siting process. Our purpose in what follows is to draw from our past work -- and from the discussions and work of others -- a sketch of the major outlines of one possible approach to power plant siting for the state. We hope in doing so to give our present views about the issues and how they might rationally be resolved, not so much to convince as to inform, stimulate fruitful ideas, and help provide the basis for constructive debate. We ourselves are not necessarily wedded to any of the discussion that follows; we find our own minds changing from time to time as we study the problem further or confront sound suggestions from others. \n\nPart I of this memorandum briefly outlines the major features of what we see as a fruitful approach to the siting problem. Sections A through E of Part I describe some elements of the approach; Section F sketches the actual siting decision process we suggest, and in doing so shows how the elements play into the process. Section G comments briefly on a suggested role for judicial review. \n\nIn Part II we attempt to reduce our ideas to a fairly precise outline for a state siting statute, and to deal with certain matters of detail not covered in Part I. Section A of Part II introduces the statutory outline by summarizing each of its provisions; Section B sets forth the outline itself. The Appendix to this memorandum depicts our suggested approach in time-line fashion; it should be helpful in reading and understanding the proposal.",
"doi": "10.7907/hkx6g-vm495",
"publisher": "California Institute of Technology",
"publication_date": "2009-10-20"
},
{
"id": "authors:2z9px-ffs97",
"collection": "authors",
"collection_id": "2z9px-ffs97",
"cite_using_url": "https://resolver.caltech.edu/CaltechEQL:EQL-R-4",
"type": "monograph",
"title": "Smog: a report to the people",
"author": [
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
},
{
"family_name": "Braly",
"given_name": "Mark",
"clpid": "Braly-Mark"
},
{
"family_name": "Easterling",
"given_name": "Mahlon",
"clpid": "Easterling-Mahlon"
},
{
"family_name": "Fisher",
"given_name": "Robert",
"clpid": "Fisher-Robert"
},
{
"family_name": "Heitner",
"given_name": "Kenneth",
"clpid": "Heitner-Kenneth"
},
{
"family_name": "Henry",
"given_name": "James",
"clpid": "Henry-James"
},
{
"family_name": "Horne",
"given_name": "Patricia J.",
"clpid": "Horne-Patricia-J"
},
{
"family_name": "Klein",
"given_name": "Burton",
"clpid": "Klein-Burton"
},
{
"family_name": "Krier",
"given_name": "James",
"clpid": "Krier-James"
},
{
"family_name": "Montgomery",
"given_name": "W. David",
"clpid": "Montgomery-W-David"
},
{
"family_name": "Pauker",
"given_name": "Guy",
"clpid": "Pauker-Guy"
},
{
"family_name": "Rubenstein",
"given_name": "Gary",
"clpid": "Rubenstein-Gary"
},
{
"family_name": "Trijonis",
"given_name": "John",
"clpid": "Trijonis-John-C"
}
],
"abstract": "The Environmental Quality Laboratory (EQL) traces its origins to a series of discussions initiated by Caltech President Harold Brown on the feasibility of a Caltech Air Pollution Laboratory aimed at alleviating the smog problem in the South Coast Air Basin. In an address to the Institute for the Advancement of Engineering on February 28, 1970, [1] Dr. Brown summarized the main conclusions of a faculty-JPL study group on smog led by Professor Carver Mead that preceded the formation of the EQL. To quote from Dr. Brown's address, the most important conclusion \"is that there are other factors which are as important or more important than the technological ones.... Unless expert social scientists are available -- and I mean not only economists to examine the economic balance, but political scientists, sociologists, psychologists, and so on -- the study will be done in too narrow a context. Although it will give the right answers to its own questions, it will prove to have overlooked questions more important than those which it asked.\" \n\nOur experience in working on the smog problem over the past year fully confirms Dr. Brown's observations. The EQL team engaged in this study included social scientists, lawyers, engineers, and graduate and undergraduate students. Each of us had to learn that the social, cultural, legal, economic and technical factors interact strongly and therefore cannot be treated separately. In addition to innumerable internal debates, seminars and memos, we had the benefit of numerous discussions with people in industry, in environmental action groups, and in government at all levels who are concerned with air pollution. \n\nAt the outset of the EQL study we made the decision to consider only those air pollution control strategies that comply with the spirit (if not the letter) of the Clean Air Act of 1970. In the spirit of that act this report describes a \"management standards\" approach for achieving drastic reductions in the number of \"smoggy\" days in the South Coast Air Basin of California by the end of 1977. In order to illustrate the kinds of control measures that are required if the management air quality standards are to be satisfied, we chose one particular control strategy for detailed study. This strategy, called EQL Strategy # 1, is based on new \"technical\" control measures on stationary sources and used motor vehicles, combined with a set of social and economic incentives and disincentives designed to encourage the shift to low-pollution motor vehicles, to encourage the use of multiple-occupancy vehicles (buses, carpools, etc.), and to halt or at least reduce the annual rate of increase in gasoline consumption in the Basin. [2] If EQL Strategy # 1 is followed, we estimated that the average number of days per year on which the California ambient air quality standard on photochemical oxidants is violated would be reduced from 241 days in 1970 to 50 days by the end of 1975, and to 25 days by the end of 1977. \n\nThe measures we propose are neither painless not inexpensive. We did not find any \"magic solutions.\" For example, the cost of EQL Strategy # 1 for this Basin is estimated at about one billion dollars through the end of 1975, or about $100 per head. Whether or not the results that could be achieved are worth the effort and expense is up to the people of the South Coast Air Basin to decide. \n\nAn earlier version of this report called EQL Report # 4, dated January 15, 1972, consisted of Part I, which contained a summary of EQL Strategy 1, and Part II, which briefly outlined the legislative and administrative actions required. The present final edition of the EQL air pollution report contains a revised and updated version of Part I and a new Part II, entitled \"Supporting Information and Analysis.\" \n\nOur work on the short-term (1972-1977) air pollution control problem raised important and difficult questions about the long-range (1982-2000) problem of controlling air pollution in the South Coast Air Basin. Members of the EQL staff are studying new technologies, social and economic incentives, modes of transportation and patterns of land use and development in an attempt to formulate a long-range strategy. \n\nLester Lees \nDirector, Environmental Quality Laboratory \nPasadena, California \nJune 15, 1972 \n\n\n[1] Brown, H.: \"The University and Environmental Research,\" Bulletin of the California Institute of Technology, Vol. 79, No. 1, March 7, 1970.\n[2] Some of these technical control measures are also included in the Implementation Plan submitted by the State to the U.S. Environmental Protection Agency in February, 1972.",
"doi": "10.7907/Z93B5X30",
"publisher": "California Institute of Technology",
"publication_date": "2007-09-18"
},
{
"id": "authors:rrk5j-53w74",
"collection": "authors",
"collection_id": "rrk5j-53w74",
"cite_using_url": "https://resolver.caltech.edu/CaltechEQL:EQL-R-1",
"type": "monograph",
"title": "People, power and pollution: environmental and public interest aspects of electric power plant siting",
"author": [
{
"family_name": "Borrelli",
"given_name": "Peter",
"clpid": "Borrelli-P"
},
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
},
{
"family_name": "Easterling",
"given_name": "Mahlon",
"clpid": "Easterling-M"
},
{
"family_name": "Pauker",
"given_name": "Guy",
"clpid": "Pauker-G"
},
{
"family_name": "Klein",
"given_name": "Burton H.",
"clpid": "Klein-B-H"
},
{
"family_name": "Poppe",
"given_name": "Robert",
"clpid": "Poppe-R"
}
],
"abstract": "Explanatory Note: \n\nOn March 16, 1971, the National Academy of Engineering convened the Forum of the Committee on Power Plant Siting (COPPS) in Washington, D.C. After two days of plenary sessions the members of the three main working groups met for three days to begin drafting their reports. Four of the authors of the present report (Borrelli, Easterling, Lees and Poppe) constituted the sub-group on Environmental Aspects of Siting of Working Group II-Systems Approach to Site Selection. Intensive discussions in Washington in this sub-group, and the subsequent exchange of draft sections by mail, convinced us that we should go far beyond our original assignment and probe into all aspects of power plant siting, especially the public interest factors. During a second intensive working session in Pasadena, California, on April 22 and 23, 1971, we were joined by Guy Pauker and Burton H. Klein, who also participated in the subsequent redrafting of the final report. We are grateful to the NAE-COPPS for stimulating our thinking on this important and difficult problem. However, the final report is solely our responsibility as individuals and the responsibility of the Caltech Environmental Quality Laboratory. \n\nLester Lees \n\nDirector, Environmental Quality Laboratory",
"doi": "10.7907/Z9TD9V7P",
"publisher": "California Institute of Technology",
"publication_date": "2007-09-14"
},
{
"id": "authors:k0154-nkk36",
"collection": "authors",
"collection_id": "k0154-nkk36",
"cite_using_url": "https://resolver.caltech.edu/CaltechEQL:EQL-R-7",
"type": "monograph",
"title": "Time factors in slowing down the rate of growth of demand for primary energy in the United States",
"author": [
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
},
{
"family_name": "Lo",
"given_name": "Mingin Philip",
"clpid": "Lo-Mingin-Philip"
}
],
"abstract": "The purpose of this report is to identify the time scales involved in slowing down the rate of growth of primary energy consumption in the U.S., as one component of an overall energy/environment strategy designed to limit the required volume of energy imports from overseas. Two important energy-consuming sectors of the economy are chosen as illustrative examples: (1) the \"automobile\" as a total system (25%); (2) space heating, air conditioning and water heating in the residential sector (22%). Efficient, light-weight vehicles are introduced into the automobile population by allocating an increasing percentage of new car production to such vehicles year by year until some fixed percentage is attained. Parametric calculations show that significant reductions in the annual rate of energy consumption by automobiles can be achieved if (a) the fuel consumption of efficient vehicles is 60% or less of \"standard\" vehicles; (b) the increment in percentage of new car production devoted to efficient vehicles is not less than 8% per year; (c) the efficient vehicles are \"frozen\" at not less than 80% or more of all new car production at the end of an eight to ten year period. In the residential sector the \"turnover\" rate is comparatively low, and the calculated reduction in annual energy growth rate produced by energy-conserving measures is modest, as expected, unless a \"retrofit\" rate of older living units of at least 2% per year can be attained. \n\nThese two components of an energy-conserving policy taken together would bring the growth rate in U. S. primary energy demand down from its present rate of 4.2% per year to about 2.8% per year by 1985. Reductions in the annual growth rate of the remaining 50% of U.S. primary energy consumption that seem quite feasible would bring the overall growth rate down to about 2.5% per year by 1985. If reductions in growth rate of this magnitude could in fact be achieved, energy imports would peak in the mid-1980s at a level no higher than about 60% above the present (1973) volume of imports. Incentives and disincentives designed to bring about this slowdown in the rate of U. S. energy consumption are discussed briefly.",
"doi": "10.7907/Z9W37T8G",
"publisher": "California Institute of Technology",
"publication_date": "2007-09-14"
},
{
"id": "authors:t9zbq-7at93",
"collection": "authors",
"collection_id": "t9zbq-7at93",
"cite_using_url": "https://resolver.caltech.edu/CaltechEQL:EQL-R-2",
"type": "monograph",
"title": "Implications of the growth in demand for commercial and industrial electrical energy in the South Coast Air Basin",
"author": [
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
}
],
"abstract": "An examination of statistical data for the period 1960-1970 shows a simple correlation between the growth in demand for commercial electrical energy in the South Coast Air Basin and the growth in commercial floor area and in electrical loading per square foot. Demand for industrial electrical energy correlates strongly with value added by manufacture and with kilowatt-hours per dollar of value added; growth in manufacturing floor area is a secondary factor. These simple correlations are utilized to forecast future demand for electrical energy in the Basin in terms of plausible \"minimum\" and \"maximum\" rates of economic growth. Comparisons between these demand projections and conservative estimates of available electrical generating capacity bring out the \"tightness\" of the short-run demand-supply situation. A \"management standard\" for growth in demand for electrical energy of 5% per year is suggested as a goal for the mid-1970's. Long-range implications of environmental, land use and technological constraints on electrical energy supply are examined and related to possible limitations on the rate of economic expansion in the South Coast Air Basin. Conversely, one can utilize the results of this study to estimate the relationship between a desired rate of economic growth and the demand for electrical energy.",
"doi": "10.7907/t9zbq-7at93",
"publisher": "California Institute of Technology",
"publication_date": "2007-09-14"
},
{
"id": "authors:15nd6-wp673",
"collection": "authors",
"collection_id": "15nd6-wp673",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KOFpof84",
"type": "article",
"title": "Theory of evaporation and condensation",
"author": [
{
"family_name": "Koffman",
"given_name": "L. D.",
"clpid": "Koffman-L-D"
},
{
"family_name": "Plesset",
"given_name": "M. S.",
"clpid": "Plesset-M-S"
},
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
}
],
"abstract": "The theory of evaporation and condensation is considered from a kinetic theory approach with a particular interest in the continuum limit. The moment method of Lees is used to solve the problem of the steady flow of vapor between a hot liquid surface and a cold liquid surface. By incorporating the singular nature of the problem, the forms of the continuum flow profiles found by Plesset are recovered. The expression for mass flux has the form of the Hertz\u2013Knudsen formula but is larger by a factor of 1.665. A result of the theory is that the temperature profile in the vapor for the continuum problem is inverted from what would seem physically reasonable. This paradox is significant in that it casts a shadow of doubt on the fundamental theory.",
"doi": "10.1063/1.864716",
"issn": "0031-9171",
"publisher": "Physics of Fluids",
"publication": "Physics of Fluids",
"publication_date": "1984-04-01",
"series_number": "4",
"volume": "27",
"issue": "4",
"pages": "876-880"
},
{
"id": "authors:bqedx-0hz09",
"collection": "authors",
"collection_id": "bqedx-0hz09",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140625-131747244",
"type": "article",
"title": "Oxidant and precursor trends in the metropolitan Los Angeles region",
"author": [
{
"family_name": "Trijonis",
"given_name": "John",
"clpid": "Trijonis-J-C"
},
{
"family_name": "Peng",
"given_name": "Ted",
"clpid": "Peng-T-K"
},
{
"family_name": "McRae",
"given_name": "Gregory",
"clpid": "McRae-G-J"
},
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
}
],
"abstract": "This paper describes recent historical trends in oxidant and precursors in the Los Angeles region. Control strategies and basinwide emission trends for nitrogen oxides and reactive hydrocarbons are documented year by year from 1965 to 1974. Trends in the geographic distribution of emissions are illustrated by computing net percentage emission changes over the decade for individual counties. The changes in emissions are compared with changes in ambient precursor concentrations and oxidant concentrations. We find that many of the changes in monitored air quality can be explained by trends in both total emissions and the spatial distribution of emissions.",
"doi": "10.1016/0004-6981(78)90083-5",
"issn": "1352-2310",
"publisher": "Elsevier",
"publication": "Atmospheric Environment",
"publication_date": "1978",
"series_number": "6-7",
"volume": "12",
"issue": "6-7",
"pages": "1413-1420"
},
{
"id": "authors:byse9-ytd83",
"collection": "authors",
"collection_id": "byse9-ytd83",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140918-095434957",
"type": "book_section",
"title": "Oxidant and precursor trends in the metropolitan Los Angeles region",
"author": [
{
"family_name": "Trijonis",
"given_name": "John",
"clpid": "Trijonis-John-C"
},
{
"family_name": "Peng",
"given_name": "Ted",
"clpid": "Peng-Ted-K"
},
{
"family_name": "McRae",
"given_name": "Gregory",
"clpid": "McRae-Gregory-J"
},
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
}
],
"contributor": [
{
"family_name": "Dimitriades",
"given_name": "Basil",
"clpid": "Dimitriades-Basil"
}
],
"abstract": "This paper describes recent htstorical trends in oxidant and precursors in the Los Angeles region. Control strategies and basin-wide emission trends for nitrogen oxides and reactive hydrocarbons are documented year by year\nfrom 1965 to 1974. Trends in the geographic distribution of emissions are illustrated by computing net percentage emission changes over the decade for individual counties. The changes in emissions are compared to changes in ambient precursor concentrations and oxidant concentrations. It is found that many of the changes in monitored air quality can be explained by trends in total emissions and in the spatial distribution of emissions.",
"publisher": "Environmental Protection Agency",
"publication_date": "1977"
},
{
"id": "authors:x7hqb-87j77",
"collection": "authors",
"collection_id": "x7hqb-87j77",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120810-112829770",
"type": "article",
"title": "Finite-Amplitude Instability of the Compressible Laminar\n Wake. Strongly Amplified Disturbances",
"author": [
{
"family_name": "Liu",
"given_name": "J. T. C.",
"clpid": "Liu-J-T-C"
},
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
}
],
"abstract": "The interaction between mean flow and finite\u2010amplitude disturbances in certain experimentally observed unstable, compressible laminar wakes is considered theoretically without explicitly assuming small amplification rates. Boundary\u2010layer form of the two\u2010dimensional mean\u2010flow momentum, kinetic energy and thermal energy equations and the time\u2010averaged kinetic energy equation of spatially growing disturbances are recast into their respective von K\u00e1rm\u00e1n integral form which show the over\u2010all physical coupling. The Reynolds shear stresses couple the mean flow and disturbance kinetic energies through the conversion mechanism familiar in low\u2010speed flows. Both the mean flow and disturbance kinetic energies are coupled to the mean\u2010flow thermal energy through their respective viscous dissipation. The work done by the disturbance pressure gradients gives rise to an additional coupling between the disturbance kinetic energy and the mean\u2010flow thermal energy. The compressibility transformation suggested by work on turbulent shear flows is not applicable to this problem because of the accompanying ad hoc assumptions about the disturbance behavior. The disturbances of a discrete frequency which corresponds to the most unstable fundamental component, are first evaluated locally. Subsequent mean\u2010flow and disturbance profile\u2010shape assumptions are made in terms of a mean\u2010flow\u2010density Howarth variable. The compressibility transformation, which cannot convert this problem into a form identical to the low\u2010speed problem of Ko, Kubota, and Lees because of the compressible disturbance quantities, nevertheless, yields a much simplified description of the mean flow.",
"doi": "10.1063/1.1692884",
"issn": "1070-6631",
"publisher": "American Institute of Physics",
"publication": "Physics of Fluids",
"publication_date": "1970-12",
"series_number": "12",
"volume": "13",
"issue": "12",
"pages": "2932-2938"
},
{
"id": "authors:k9t1y-dnm29",
"collection": "authors",
"collection_id": "k9t1y-dnm29",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141201-162815216",
"type": "article",
"title": "Near wake of a hypersonic blunt body with mass addition",
"author": [
{
"family_name": "Collins",
"given_name": "Donald J.",
"clpid": "Collins-D-J"
},
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
},
{
"family_name": "Roshko",
"given_name": "Anatol",
"clpid": "Roshko-A"
}
],
"abstract": "An experimental investigation of the steady, laminar near-wake flowfield of a two-dimensional, adiabatic, circular cylinder \u00b7with surface mass transfer has been made at a freestream Mach number of 6.0. The pressure and mass- concentration fields associated with the transfer of argon, nitrogen, or helium into the near wake were studied for mass transfer from the forward stagnation region, and from the base. For sufficiently low mass transfer rates from the base, for which a recirculating zone exists, the entire near-wake flowfield correlates with the momentum flux, not the mass flux, of the injectant, and the mass-concentration field is determined by counter-current diffusion into the reversed flow. For mass addition from the forward stagnation region, the pressure field is undisturbed and the mass- concentration field is nearly uniform in the region of reversed flow. The axial decay of argon mass concentration in the intermediate wake, downstream of the neck, is explained with the aid of an integral solution in the incompressible plane, from which the location of the virtual origin for the asymptotic far-wake solution has been derived as one result.",
"doi": "10.2514/3.5775",
"issn": "0001-1452",
"publisher": "AIAA",
"publication": "AIAA Journal",
"publication_date": "1970-05",
"series_number": "5",
"volume": "8",
"issue": "5",
"pages": "833-842"
},
{
"id": "authors:dz7g8-5mz59",
"collection": "authors",
"collection_id": "dz7g8-5mz59",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120806-104808057",
"type": "article",
"title": "Finite disturbance effect on the stability of a laminar incompressible wake behind a flat plate",
"author": [
{
"family_name": "Ko",
"given_name": "D. Ru-Sue",
"clpid": "Ko-D-R-S"
},
{
"family_name": "Kubota",
"given_name": "T.",
"clpid": "Kubota-T"
},
{
"family_name": "Lees",
"given_name": "L.",
"clpid": "Lees-L"
}
],
"abstract": "An integral method is used to investigate the interaction between a two-dimensional, single frequency finite amplitude disturbance in a laminar, incompressible wake behind a flat plate at zero incidence. The mean flow is assumed to be a non-parallel flow characterized by a few shape parameters. Distribution of the fluctuation across the wake is obtained as functions of those mean flow parameters by solving the inviscid Rayleigh equation using the local mean flow. The variations of the fluctuation amplitude and of the shape parameters for the mean flow are then obtained by solving a set of ordinary differential equations derived from the momentum and energy integral equations. The interaction between the mean flow and the fluctuation through Reynolds stresses plays an important role in the present formulation, and the theoretical results show good agreement with the measurements of Sato & Kuriki (1961).",
"doi": "10.1017/S0022112070000198",
"issn": "0022-1120",
"publisher": "Cambridge University Press",
"publication": "Journal of Fluid Mechanics",
"publication_date": "1970-02",
"series_number": "2",
"volume": "40",
"issue": "2",
"pages": "315-341"
},
{
"id": "authors:3ek0g-h0818",
"collection": "authors",
"collection_id": "3ek0g-h0818",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141210-132533513",
"type": "conference_item",
"title": "An experimental study of the near wake of a two-dimensional hypersonic blunt body with mass addition",
"author": [
{
"family_name": "Collins",
"given_name": "Donald J.",
"clpid": "Collins-D-J"
},
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
},
{
"family_name": "Roshko",
"given_name": "Anatol",
"clpid": "Roshko-A"
}
],
"abstract": "An experimental investigation of the steady, laminar near-wake flow field of a two-dimensional, adiabatic, circular cylinder with surface mass transfer has been made at a free-stream Mach number of 6.0. The pressure and mass-concentration fields associated with the transfer of argon, nitrogen or helium into the near wake were studied for mass transfer from the forward stagnation region, and from the base. For sufficiently low mass transfer rates from the base, for which a recirculating zone exists, the entire near-wake flow field correlates with the momentum flux, not the mass flux, of the injectant, and the mass-concentration field is determined by counter-current diffusion into the reversed flow. For mass addition from the forward stagnation region, the pressure field is undisturbed and the mass-concentration field is nearly uniform in the region of reversed flow. The axial decay of argon mass concentration in the intermediate wake, downstream of the neck, is explained with the aid of an integral solution in the incompressible plane, from which the location of the virtual origin for the asymptotic far-wake solution has been derived as one result.",
"doi": "10.2514/6.1969-67",
"publication_date": "1969-01"
},
{
"id": "authors:hpgrg-3pn34",
"collection": "authors",
"collection_id": "hpgrg-3pn34",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170807-144358436",
"type": "article",
"title": "Reply by Authors to A. Goldburg",
"author": [
{
"family_name": "Behrens",
"given_name": "Wilhelm",
"clpid": "Behrens-W"
},
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
}
],
"abstract": "Goldburg has apparently misunderstood the significance of the local minimum critical Reynolds number (Re_f, d)min, er. When the effective turbulent diffusivity \u03b5_T is smaller than the kinematic viscosity, v_i, the work done by the Reynolds stresses is more than counterbalanced by the rate of viscous dissipation. Thus, turbulence in the wake cannot exist when (\u03b5_T/u_fd) < (v_f/u_jd), or when Re_f, d < (Re_f, d)min, er, any more than turbulent flow in a pipe can exist below a critical Reynolds number of 2000. If one chooses to call this \"quenching,\" that is a problem in semantics and not in fluid mechanics.",
"doi": "10.2514/3.55155",
"issn": "0001-1452",
"publisher": "AIAA",
"publication": "AIAA Journal",
"publication_date": "1965-05",
"series_number": "5",
"volume": "3",
"issue": "5",
"pages": "991-992"
},
{
"id": "authors:0cazg-9fg16",
"collection": "authors",
"collection_id": "0cazg-9fg16",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131120-135449172",
"type": "article",
"title": "Kinetic\u2010Theory Description of Conductive Heat Transfer from a Fine Wire",
"author": [
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
},
{
"family_name": "Liu",
"given_name": "Chung-Yen",
"clpid": "Liu-Chung-Yen"
}
],
"abstract": "The Maxwell moment method utilizing the two\u2010sided Maxwellian distribution function is applied to the problem of conductive heat transfer between two concentric cylinders at rest. Analytical solutions are obtained for small temperature differences between the cylinders. The predicted heat transfer agrees very well with experiments performed on the heat loss from a fine wire by Bomelburg and Sch\u00e4fer, Rating, and Eucken. Comparison with results given by Grad's thirteen\u2010moment equations, and with those given by Fourier's \"law'' plus the Maxwell\u2014Smoluchowski temperature\u2010jump boundary condition, shows that the two\u2010sided character of the distribution function is a crucial factor in problems involving surface curvature.",
"doi": "10.1063/1.1706498",
"issn": "1070-6631",
"publisher": "American Institute of Physics",
"publication": "Physics of Fluids",
"publication_date": "1962-10",
"series_number": "10",
"volume": "5",
"issue": "10",
"pages": "1137-1148"
},
{
"id": "authors:e6ywd-87995",
"collection": "authors",
"collection_id": "e6ywd-87995",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LEEnacarpt876",
"type": "monograph",
"title": "The Stability of the Laminar Boundary Layer",
"author": [
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
}
],
"abstract": "The present papcr is a continuation of a theoretical investigation of the stability of the laminar boundary layer in a compressible fluid. An approximate estimate for the minimum critical Reynolds number Re[sub]cr[sub-sub]min, or stability limit, is obtained in terms of the distribution of the kinematic viscosity and the product of the mean density [rho][super][bar]* and mean vorticity [formula] across the\nboundary layer. With the help of this estimate for Re[sub]cr[sub-sub]min it is shown that withdrawing heat from the fluid through the solid surface increases RRe[sub]cr[sub-sub]min and stabilizes the flow, as compared with the flow over an insulated surface at the same Mach number. Conduction of heat to the fluid through the solid surface has exactly the opposite effect. The value of Re[sub]cr[sub-sub]min for the insulated surface decreases as the Mach number increases for the case of a uniform free-stream velocity. These general conclusions are supplemented by detailed calculations of the curves of wave number (inverse wave length) against Reynolds number for the neutral disturbances for 10 representative cases of insulated and noninsulated surfaces. \n\nSo far as laminar stability is concerned, an important difference exists between the case of a subsonic and supersonic free-stream velocity outside the boundary layer. The neutral boundary-layer disturbances that are significant for laminar stability die out exponentially with distance from the solid surface; therefore, the phase velocity c* of these disturbances is subsonic relative to the free-stream velocity [symbol] or [symbol], [symbol] where is the local sonic velocity. When [symbol]<1, (where M[sub]0 is free-stream Mach number), it follows that [inequalities] and any laminar boundary-1ayer flow is ultimately unstable at sufficiently high Reynolds numbers because of the destabilizing action of viscosity near the solid surface, as\nexplained by Prandtl for the incompressible fluid. When M[sub]0 >1, however, [inequalities]. If the quantity [forumla] is large enough negatively, the rate at which energy passes from the disturbance to the mean flow, which is proportional to [formula], can always be large enough to counterbalance the rate at which energy passes from the mean flow to the disturbance because of the destabilizing action of viscosity near the solid surface. In that case only damped disturbances exist and the laminar boundary layer is completely stable at all Reynolds numbers. This condition occurs when the rate at which heat is withdrawn from the fluid through the solid surface reaches or exceeds a critical value that depends only on the Mach number and the properties of the gas. Calculations show that for M[sub]0 > 3 (approx.) the laminar boundary-layer flow for thermal equilibrium -- where the heat conduction through the solid surface balances the heat radiated from the surface -- is completely stable at all Reynolds numbers under free-flight\nconditions if the free-stream velocity is uniform. \n\nThe results of the analysis of the stability of the laminar boundary layer must be applied with care to discussions of transition; however, withdrawing heat from the fluid through the solid surface, for example, not only increases Re[sub]cr[sub-sub]min but also decreases the initial rate of amplification of the self-excited disturbances, which is roughly proportional fo 1/[sqrt]Re[sub]cr[sub-sub]min. Thus, the effect of the thermal conditions at the solid sufice on the transition Reynolds number Re[sub]tt, is similar to the effect on Re[sub]cr[sub-sub]min. A comparison between this conclusion and experimental investigations of the effect of surface heating on transition at low speeds shows that the results of the present paper give the proper direction of this effect. \n\nThe extension of the results of the stability analysis to laminar boundary-layer gas flows with a pressure gradient in the direction of the free stream is discussed.",
"publisher": "National Advisory Committee for Aeronautics",
"publication_date": "1947"
},
{
"id": "authors:get29-pt673",
"collection": "authors",
"collection_id": "get29-pt673",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LEEnacatn1127",
"type": "monograph",
"title": "A Discussion of the Application of the Prandtl-Glauert Method to Subsonic Compressible Flow over a Slender Body of Revolution",
"author": [
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
}
],
"abstract": "The Prandtl-Glauert method for subsonic potential flow of a compressible fluid has generally been believed to lead to an increase in the pressures over a slender body of revolution by a factor 1/([sqrt](1-M[sub]1^2)) (where M[sub]1 is Mach number in undisturbed flow) as compared with the pressures in incompressible flow. Recent German work on this problem has indicated, however, that the factor 1/([sqrt](1-M[sub]1^2)) is not applicable in this case. In the present discussion a more careful application of the\nPrandtl-Glauert method to three-dimensional flow gives the following results: \n\nThe Prandtl-Glauert method does not lead to a universal velocity or pressure correction formula that is independent of the shape of the body. The factor 1/([sqrt](1-M[sub]1^2)) is applicable only to the case of two-dimensional flow. \n\nThe increase with Mach number of the pressures over a slender body of revolution is much less rapid than for a two-dimensional airfoil. An approximate formula from which the increase can be estimated is derived theoretically. \n\nThe increase with Mach number of the maximum axial interference velocity on a slender body of revolution in a closed wind tunnel is given approximately by the factor 1/((1-M[sub]1^2)^-3/2), rather than by the factor 1/([sqrt](1-M[sub]1^2)) previously obtained by Goldstein and Young and by Tsien and Lees.",
"publisher": "National Advisory Committee for Aeronautics",
"publication_date": "1946-09"
},
{
"id": "authors:x2tja-rc845",
"collection": "authors",
"collection_id": "x2tja-rc845",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LEEnacatn1115",
"type": "monograph",
"title": "Investigation of the Stability of the Laminar Boundary Layer in a Compressible Fluid",
"author": [
{
"family_name": "Lees",
"given_name": "Lester",
"clpid": "Lees-L"
},
{
"family_name": "Lin",
"given_name": "Chia Chiao",
"clpid": "Lin-C-C"
}
],
"abstract": "In the present report the stability of two-dimensional laminar flows of a gas is investigated by the method of small perturbations. The chief emphasis is placed on the case of the laminar boundary layer. \n\nPart I of the present report deals with the general mathematical theory. The general equations governing one normal mode of the small velocity and temperature disturbances are derived and studied in great detail. It is found that for Reynolds numbers of the order of those encountered in most aerodymnic problems, the temperature disturbances have only a negligible effect on those particular velocity solutions which depend primarily on the viscosity coefficient (\"viscous solutions\"). Indeed, the latter are actually of the same form in the compressible fluid as in the incompressible fluid, at least to the first\napproximation. Because of this fact, the mathematical analysis is greatly simplified. The final equation determining the characteristic values of the stability problem depends on the \"inviscid solutions\" and the function of Tietjens in a manner very similar to the case of the incompressible fluid. The second viscosity coefficient and the coefficient of heat conductivity do not enter the problem; only the ordinary coefficient of viscosity near the solid surface is involved. \n\nPart II deals wlth the limiting case of infinite Reynolds numbers. The study of energy relations is very much emphasized. It is shown that the disturbance will gain energy from the main flow if the gradient of the product of mean density and mean vorticity near the solid surface has a sign opposite to that near the outer edge of the boundary layer. \n\nA general stability criterion has been obtained in terms of the gradient of the product of density and vorticity, analogous to the Rayleigh-Tollmien criterion for the case of an incompressible fluid. If this gradient vanishes for some value of the velocity ratio of the main flow exceeding 1 - 1/M (where M is the free stream Mach number), then neutral and self-excited \"subsonic\" disturbances exist in the inviscid fluid. (The subsonic disturbances die out rapidly with distance from the solid surface.) The conditions for the existence of other types of disturbance have not yet been established to this extent of exactness. A formula has been worked out to give the amplitude ratio of incoming and reflected sound waves. \n\nIt is found in the present investigation that when the solid boundary is heated, the boundary layer flow is destabilized through the change in the distribution of the product of density and vorticity, but stabilized through the increase of kinematic viscosity near the solid boundary. When the solid boundary is cooled, the situation is just the reverse. The actual extent to which these two effects counteract each\nother can only be settled by actual computation or some approximate estimstes of the minimum critical Reylolds number. This question will be investigated in a subsequent report. \n\nPart III deals with the stability of laminar flows in a perfect gas with the effect of viscosity included. The method for the numerical computation of the stability limit is outlined; detailed numerical calculations will be carried out in a subsequent report.",
"publisher": "National Advisory Committee for Aeronautics",
"publication_date": "1946-09"
}
]