Boundary layer development upon swept plate with streamwise pressure gradient

ABSTRACT BOUNDARY LAYER DEVELOPMENT UPON SWEPT PLATE WITH STREAMWISE PRESSURE GRADIENT USKANER (KARABAŞ), Fatma Ph. D. inMeckEng. Supervisor: Prof. Dr. Ömer T. GÖKSEL April 1997, 300 Pages The three-dimensional boundary layer development over swept flat plates subjected to constant pressure gradients was investigated experimentally. A computer controlled data aquisition and analysis unit with traversing mechanisms was build to measure the velocity and flow angles in the boundary layer. For the collection of experimental data and calculation of boundary layer parameters, a computer program called "SWEPT PLATE" was prepared and used in this work. The effect of plate sweep angles and pressure gradients on transition characteristics and boundary layer development were investigated upon test plates having 10°, 20°, 35° and 50° sweep angles which were subjected to two favorable and two adverse pressure gradients. The effect of crossflow and streamwise instability on the occurrence of transition upon the swept plates were determined. Correlations between start of transition Reynolds number and intermittency in transitional range were obtained. The crossflow and streamwise velocity profiles in the boundary layer of the swept plates are presented. Correlations are found to determine local skin friction coefficient for three- dimensional laminar, transitional and turbulent boundary layer upon the swept plates. Key words: Swept plates, Pressure gradients, Transition, Three-dimensional boundary layers, Skin friction, Crossflow, Data aquisition. m