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Some unsteady features of turbulent boundary layersAhn, Seungki January 1986 (has links)
For steady free-stream, zero and favorable pressure gradient turbulent boundary layers, the unsteadiness in the form of turbulent fluctuations was investigated. Phase ensemble-averaged flow characteristics of a large amplitude periodic unsteady turbulent boundary layer was also investigated at a reduced frequency k = 0.61 based on the length of the converging and diverging test section with amplitude to mean velocity ratio of 0.8.
In steady flow cases, both zero and favorable pressure gradient flows show good two-dimensional flow characteristics and mean flow characteristics are compared with other researchers’ data. Measured power spectral data show good agreement with those of Klebanoff, Ueda and Hinze, Perry, Lim and Henbest for the zero pressure gradient flows and Jones and Launder for the favorable pressure gradient flow. The power spectral data measured in the turbulent wall region of the zero pressure gradient flow closely follow the model equation proposed by Perry, Lim and Henbest. Convective wave speed also show good agreement with those of Favre, Gaviglio and Dumas and Sternberg within the experimental uncertainties. In the inner region of the boundary layer where y+ < 40, convective wave speed is higher than local mean velocity at all eddy scales as observed by Kline, Reynolds, Schraub and Runstadler.
In the unsteady flow case, in the absence of flow reversal, the flow behaves in a quasi-steady manner and can be described by the steady flow structure as in the case of moderate amplitude flows. The Ludwieg·Tillmann skin friction equation and the Perry-Schofield universal velocity defect law hold at these phases. Except the laminariscent velocity profile observed during the acceleration phases, the large amplitude unsteady flow shows basically the same flow characteristics as the moderate amplitude flows. / Master of Science
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An Experimental Study of the Effects of Aqueous Polymer Solutions on a Liquid Boundary LayerShen, Chi-Hung 05 1900 (has links)
<p> This thesis is an experimental study of the effects of injecting dilute polymer solutions into a turbulent boundary layer developed on a flat plate submerged in water.</p> <p> A flat plate having a plexiglass surface together with a separate leading edge piece were specially designed for observing the boundary layer phenomena. Aqueous polymer solutions were
introduced into the boundary layer through a slit situated in the leading edge piece. Hot-film anemometer technique was employed in the measurements of velocity profiles, turbulence intensities and lateral correlation coefficients at several locations on the plate. The investigation was carried out for two Reynolds Numbers, based on the length of the plate, of 2.4 x 10^5 and 6.4 x 10^5. The variation in the drag force with respect to the polymer concentrations and the injection rates was assessed based on the velocity profile data. It was found that the momentum diffusivity was smaller than for pure water, and that the presence of the polymer molecules seemed to promote a more uniform distribution of the sizes of the turbulence eddies.</p> / Thesis / Master of Engineering (MEngr)
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The structure and development of streamwise vortex arrays embedded in a turbulent boundary layerWendt, Bruce James January 1991 (has links)
No description available.
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The interacting boundary layer and acoustic field generated by vortex motion /Chuang, Fu-sheng January 1986 (has links)
No description available.
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The solution of plane harmonic and biharmonic boundary value problems in the theory of elasticity /Lo, Chunchang January 1964 (has links)
No description available.
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Analytical investigation of magnetohydrodynamic boundary layers with Hall effects /Pfannebecker, George William January 1966 (has links)
No description available.
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Boundary layer separation control and wall temperature control by tangential fluid injection /Haering, George William January 1968 (has links)
No description available.
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The influences of artificially induced turbulence upon boundary-layer transition in supersonic flows /Olson, Lawrence Elroy January 1970 (has links)
No description available.
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Subsonic and transonic flow over sharp and round nosed nonlifting airfoils /Olsen, James Joseph January 1976 (has links)
No description available.
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An experimental study of turbine airfoil pressure surface boundary layer transition region and wake characteristics /Cox, Wesley Roland January 1978 (has links)
No description available.
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