[
    {
        "id": "authors:ahkx1-xgc75",
        "collection": "authors",
        "collection_id": "ahkx1-xgc75",
        "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170801-083712062",
        "type": "book_section",
        "title": "An experimental study of hypersonic wakes behind wedges at angle of attack",
        "author": [
            {
                "family_name": "Behrens",
                "given_name": "W.",
                "clpid": "Behrens-W"
            }
        ],
        "abstract": "Experimental measurements of mean flow properties of hypersonic wakes behind wedges of 20\u00b0 included angle were conducted for angles of attack up to 25\u00b0 at Mach number 6, with Reynolds number based on wedge base height ranging from 7,000 to 55,000.  The near and far wake structures were determined, including streamlines and velocity profiles, over a down-stream distance of 60 base heights. The base pressure is insensitive to incidence within about 17\u00b0.  At higher incidence, flow separation occurs on the leeward surface.  The near wake flow field changes accordingly.  The far viscous wake (x/H > 4) changes with increasing incidence because of the increasing differences of the inviscid flow quantities at the leeward and windward edges of the viscous wake.  The wake static pressure, which increases with incidence, viscous wake edge velocities, edge Mach number, edge temperatures and flow inclination of the real flow (directed towards the leeward side) compare favorably with a simple inviscid shock expansion model.  In the laminar wake flows the wake widths, minimum velocities, minimum Mach numbers and maximum temperatures change little with incidence.  However, in the transitional wake flows, the \"break-away\" phenomenon is observed and transition from laminar to turbulent flow moves upstream as angle of attach increases.",
        "doi": "10.2514/6.1971-563",
        "publisher": "AIAA",
        "publication_date": "1971-06"
    },
    {
        "id": "authors:s7s5c-vvj29",
        "collection": "authors",
        "collection_id": "s7s5c-vvj29",
        "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170731-145242715",
        "type": "book_section",
        "title": "Separation of a supersonic turbulent boundary layer by a forward facing step",
        "author": [
            {
                "family_name": "Behrens",
                "given_name": "W.",
                "clpid": "Behrens-W"
            }
        ],
        "abstract": "The mean flow and fluctuations were measured in the undistributed turbulent boundary layer, the separated flow region and on top of the step. The freestream Mach number was 4.0 and the boundary layer Reynolds number based on momentum thickness was 4,100. The model was large enough to allow reversed flow profile measurements and to insure two-dimensionality of the separated flow. For an aspect ratio (span between fences/step height) of 9.4, the back flow profiles show three-dimensionality effects. The mean flowfield is described in detail. In the \"separation region\" large normal and axial pressure gradients exist. The angle of the inviscid flow after separation is 12 1/2\u00b0 In the nearly constant pressure separated flow region the forward velocity profiles up to 2H of the step are similar and nearly similar closer to the step. The entrainment rate of the forward flow \u03bb_e = \u03c1_0v_0/ \u03c1_eu_e = .010. Close correspondence of the forward flow with the turbulent boundary layer with injection at the same \u03bb_e was found.  The reversed flow velocity reaches 0.37 u_e, close to the step (< 1H) and decays slowly to zero at separation (x/H = 4.25).  The center of the recirculating vortex is closer to the step than 0.7H.  On top of the step the mean turbulent boundary layer attains nearly similarity shape within one step height wheras the fluctuation distributions lag considerably.  In the separated flow region most of the fluctuation energy is in random large scale low frequency fluctuations.",
        "doi": "10.2514/6.1971-127",
        "publisher": "AIAA",
        "publication_date": "1971-01"
    },
    {
        "id": "authors:fk1td-tff45",
        "collection": "authors",
        "collection_id": "fk1td-tff45",
        "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170807-153908350",
        "type": "book_section",
        "title": "Experimental investigation of the effects of base mass addition on the near wake of a slender body",
        "author": [
            {
                "family_name": "Lewis",
                "given_name": "John E.",
                "clpid": "Lewis-J-E"
            },
            {
                "family_name": "Behrens",
                "given_name": "Wilhelm",
                "clpid": "Behrens-W"
            },
            {
                "family_name": "Collins",
                "given_name": "Donald J.",
                "clpid": "Collins-D-J"
            }
        ],
        "abstract": "The near wake of a two-dimensional wedge was studied at Mach 4.  Static pressure, Pitot pressure, total temperature, injectant concentration and hot-wire fluctuations were measured.  Helium, argon and SF_6 were injected into the base, and their diffusion in laminar and turbulent wakes was studies.  The locations of the wake stagnation points as a function of injection rate, and the critical rates required to eliminate the recirculation flow were determined.  It was found that the Tear-wake flow with injection does not scale with the mass flux, nor do the momentum or the volume fluxes serve to correlate the data over the entire range of injection.  Fluctuation measurements show that SF_6 has a destabilizing effect on the wake, whereas helium has a stabilizing influence, compared to the wake without injection.  Model cooling (T_W/T_0\u221e = 0.25) resulted in a forward shift of the rear stagnation point and a pronounced decrease in both the velocity defect and the wake width but had a lesser effect on the distribution of the injected species.",
        "doi": "10.2514/6.1970-110",
        "publisher": "AIAA",
        "publication_date": "1970-01"
    },
    {
        "id": "authors:tayhb-2fd86",
        "collection": "authors",
        "collection_id": "tayhb-2fd86",
        "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170807-145720584",
        "type": "book_section",
        "title": "Fluctuation measurements in the near wake of a slender wedge at Mach 4.0 with and without base injection",
        "author": [
            {
                "family_name": "Behrens",
                "given_name": "W.",
                "clpid": "Behrens-W"
            },
            {
                "family_name": "Lewis",
                "given_name": "John E.",
                "clpid": "Lewis-J-E"
            }
        ],
        "abstract": "An experimental investigation of the turbulent and transitional near wake of an adiabatic, slender wedge with and without base injection was performed in the JPL Supersonic Wind Tunnel at Mach 4.  Two different quantities were measured with a constant current hot wire anemometer, the mean square fluctuation intensity (f \u2013 0.1 to 80 KC), and the frequency spectrum of the fluctuations (f = 5 to 200 KC, bandwidth 0.2 KC).  The various flow regions of the near wake were identified and the growth and decay of flow fluctuations were determined.  Helium and nitrogen were used as injectants and similar effects were obtained when He = N2.  The flow fluctuations of the turbulent boundary layer remnant rapidly decayed during the expansion, and the inner shear layers and the reverse flow region which they bound were laminar.  Base injection was found to significantly alter the near wake instability mechanism, which resulted in the delay of wake transition.",
        "doi": "10.2514/6.1968-100",
        "publisher": "AIAA",
        "publication_date": "1968-01"
    }
]