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A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenTue, 16 Apr 2024 15:32:49 +0000Motion of a sphere in the presence of a plane interface.
Part 1. An approximate solution by generalization
of the method of Lorentz
https://resolver.caltech.edu/CaltechAUTHORS:20120726-090448676
Authors: {'items': [{'id': 'Lee-S-H', 'name': {'family': 'Lee', 'given': 'S. H.'}}, {'id': 'Chadwick-R-S', 'name': {'family': 'Chadwick', 'given': 'R. S.'}}, {'id': 'Leal-L-G', 'name': {'family': 'Leal', 'given': 'L. G.'}}]}
Year: 1979
DOI: 10.1017/S0022112079001981
The motion of a sphere in the presence of a fluid-fluid interface is studied. First, a solution is derived for a point force near a plane interface. Then the solution is extended to include the higher-order terms which are required to describe the motion of a solid sphere. Singularities of higher orders at the centre of the sphere are obtained by using the method of reflexions. For a fluid–fluid interface with an arbitrary viscosity ratio, the drag force and the hydrodynamic torque are calculated for the special cases of motion of a sphere perpendicular and parallel to the interface. In addition, the rotational motion of a sphere is also investigated.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/19h0b-hpx27Motion of a sphere in the presence of a plane interface.
Part 2. An exact solution in bipolar co-ordinates
https://resolver.caltech.edu/CaltechAUTHORS:20120720-080629829
Authors: {'items': [{'id': 'Lee-S-H', 'name': {'family': 'Lee', 'given': 'S. H.'}}, {'id': 'Leal-L-G', 'name': {'family': 'Leal', 'given': 'L. G.'}}]}
Year: 1980
DOI: 10.1017/S0022112080000109
A general solution for Stokes' equation in bipolar co-ordinates is derived, and then applied to the arbitrary motion of a sphere in the presence of a plane fluid/fluid interface. The drag force and hydrodynamic torque on the sphere are then calculated for four specific motions of the sphere; namely, translation perpendicular and parallel to the interface and rotation about an axis which is perpendicular and parallel, respectively, to the interface. The most significant result of the present work is the comparison between these numerically exact solutions and the approximate solutions from part 1. The latter can be generalized to a variety of particle shapes, and it is thus important to assess their accuracy for this case of spherical particles where an exact solution can be obtained. In addition to comparisons with the approximate solutions, we also examine the predicted changes in the velocity, pressure and vorticity fields due to the presence of the plane interface. One particularly interesting feature of the solutions is the fact that the direction of rotation of a freely suspended sphere moving parallel to the interface can either be the same as for a sphere rolling along the interface (as might be intuitively expected), or opposite depending upon the location of the sphere centre and the ratio of viscosities for the two fluids.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/0fdda-tvz54Low-Reynolds-number flow past cylindrical bodies of arbitrary cross-sectional shape
https://resolver.caltech.edu/CaltechAUTHORS:20120627-100920779
Authors: {'items': [{'id': 'Lee-S-H', 'name': {'family': 'Lee', 'given': 'S. H.'}}, {'id': 'Leal-L-G', 'name': {'family': 'Leal', 'given': 'L. G.'}}]}
Year: 1986
DOI: 10.1017/S0022112086002616
A numerical implementation of the method of matched asymptotic expansions is proposed to analyse two-dimensional uniform streaming flow at low Reynolds number past a straight cylinder (or cylinders) of arbitrary cross-sectional shape. General solutions for both the Stokes and Oseen equations in two dimensions are expressed in terms of a boundary distribution of fundamental single- and double-layer singularities. These general solutions are then converted to integral equations for the unknown distributions of singularity strengths by application of boundary conditions at the cylinder surface, and matching conditions between the Stokes and Oseen solutions. By solving these integral equations, using collocation methods familiar from three-dimensional application of 'boundary integral' methods for solutions of Stokes equation, we generate a uniformly valid approximation to the solution for the whole domain.
We demonstrate the method by considering, as numerical examples, uniform flow past an elliptic cylinder, uniform flow past a cylinder of rectangular cross-section, and uniform flow past two parallel cylinders which may be either equal in radius, or of different sizes.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/qjhkr-7z192The creeping motion of a spherical particle normal to a deformable interface
https://resolver.caltech.edu/CaltechAUTHORS:20120627-074206046
Authors: {'items': [{'id': 'Geller-A-S', 'name': {'family': 'Geller', 'given': 'A. S.'}}, {'id': 'Lee-S-H', 'name': {'family': 'Lee', 'given': 'S. H.'}}, {'id': 'Leal-L-G', 'name': {'family': 'Leal', 'given': 'L. G.'}}]}
Year: 1986
DOI: 10.1017/S0022112086000538
Numerical results are presented for the approach of a rigid sphere normal to a deformable fluid-fluid interface in the velocity range for which inertial effects may be neglected. Both the case of a sphere moving with constant velocity, and that of a sphere moving under the action of a constant non-hydrodynamic body force are considered for several values of the viscosity ratio, density difference and interfacial tension between the two fluids. Two distinct modes of interface deformation are demonstrated: a film drainage mode in which fluid drains away in front of the sphere leaving an ever-thinning film, and a tailing mode where the sphere passes several radii beyond the plane of the initially undeformed interface, while remaining encapsulated by the original surrounding fluid which is connected with its main body by a thin thread-like tail behind the sphere. We consider the influence of the viscosity ratio, density difference, interfacial tension and starting position of the sphere in deter-mining which of these two modes of deformation will occur.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/k20rj-br667Polarity and oxidation level of visible absorbers in model organic aerosol
https://resolver.caltech.edu/CaltechAUTHORS:20140609-104744673
Authors: {'items': [{'id': 'Kameel-F-R', 'name': {'family': 'Kameel', 'given': 'F. Rifkha'}}, {'id': 'Lee-S-H', 'name': {'family': 'Lee', 'given': 'S. H.'}}, {'id': 'Hoffmann-M-R', 'name': {'family': 'Hoffmann', 'given': 'M. R.'}, 'orcid': '0000-0001-6495-1946'}, {'id': 'Colussi-A-J', 'name': {'family': 'Colussi', 'given': 'A. J.'}, 'orcid': '0000-0002-3400-4101'}]}
Year: 2014
DOI: 10.1016/j.cplett.2014.04.033
How to parametrize the absorptivity of organic aerosols in atmospheric radiative models remains uncertain. Here we report that the λ = 400 nm absorbers in model aerosol mixtures elute as weakly polar species in reversed-phase chromatography. Typical among them, the m/z = 269 (C_(12)H_(13)O_7^−, O/C = 0.58) isomers detected by mass spectrometry possess C═O groups linked by C═C bridges. More polar species, such as the m/z = 289 (C_(11)H_(13)O_9^−, O/C = 0.82) polyacids, are instead colorless. On this basis we argue that visible absorptivity, which develops from extended conjugation among chromophores, may not increase monotonically with oxidation level.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/7sg52-f5y12Soliton microcomb operation to 778 nm
https://resolver.caltech.edu/CaltechAUTHORS:20180119-103020712
Authors: {'items': [{'id': 'Yang-Qi-Fan', 'name': {'family': 'Yang', 'given': 'Q. F.'}, 'orcid': '0000-0002-7036-1712'}, {'id': 'Lee-S-H', 'name': {'family': 'Lee', 'given': 'S. H.'}}, {'id': 'Oh-Dong-Yoon', 'name': {'family': 'Oh', 'given': 'D. Y.'}, 'orcid': '0000-0001-6716-1851'}, {'id': 'Shen-B', 'name': {'family': 'Shen', 'given': 'B.'}}, {'id': 'Wang-H', 'name': {'family': 'Wang', 'given': 'H.'}}, {'id': 'Yang-Ki-Youl', 'name': {'family': 'Yang', 'given': 'K. Y.'}, 'orcid': '0000-0002-0587-3201'}, {'id': 'Lai-Yu-Hung', 'name': {'family': 'Lai', 'given': 'Y. H.'}, 'orcid': '0000-0002-9639-6569'}, {'id': 'Yi-Xu', 'name': {'family': 'Yi', 'given': 'X.'}, 'orcid': '0000-0002-2485-1104'}, {'id': 'Vahala-K-J', 'name': {'family': 'Vahala', 'given': 'K.'}, 'orcid': '0000-0003-1783-1380'}]}
Year: 2017
DOI: 10.1109/IPCon.2017.8116040
Soliton microcombs are demonstrated at both 1064 nm and 778 nm by dispersion-engineering on-chip silica resonators. These are the shortest wavelength soliton microcombs demonstrated to date and have potential applications in optical clocks and metrology.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/xqnv2-q5k83Silicon-chip-based Brillouin lasers and soliton microcombs using an integrated ultra-high-Q silica resonator
https://resolver.caltech.edu/CaltechAUTHORS:20190506-093824581
Authors: {'items': [{'id': 'Vahala-K-J', 'name': {'family': 'Vahala', 'given': 'K.'}, 'orcid': '0000-0003-1783-1380'}, {'id': 'Yang-K-Y', 'name': {'family': 'Yang', 'given': 'K.-Y.'}}, {'id': 'Oh-D-Y', 'name': {'family': 'Oh', 'given': 'D.-Y.'}}, {'id': 'Lee-S-H', 'name': {'family': 'Lee', 'given': 'S.-H.'}}, {'id': 'Yang-Qi-Fan', 'name': {'family': 'Yang', 'given': 'Q. F.'}, 'orcid': '0000-0002-7036-1712'}, {'id': 'Yi-Xu', 'name': {'family': 'Yi', 'given': 'X.'}, 'orcid': '0000-0002-2485-1104'}, {'id': 'Shen-Boqiang', 'name': {'family': 'Shen', 'given': 'B.'}, 'orcid': '0000-0003-0697-508X'}, {'id': 'Wang-Heming', 'name': {'family': 'Wang', 'given': 'H.'}, 'orcid': '0000-0003-3861-0624'}]}
Year: 2019
DOI: 10.1364/ofc.2019.m1d.4
A monolithic ultra-high-Q silica resonator featuring an integrated silicon-nitride waveguide is described. The resonator can be configured for either high-coherence Brillouin laser action or stable microwave-rate mode locking over C-band at low pumping power.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/3w1zn-sh861