An Experimental Investigation of the Turbulent Boundary Layer Behind a Forward Facing Step in Supersonic Flow

摘要

The report presents the results of an experimental study of the effect of a disturbance, produced by a forward facing step, on the turbulent boundary layer in compressible flow. Boundary layer total pressure surveys and direct skin friction measurements were made at six stations on each of two test surfaces. One surface was smooth and the other surface had an 0.080-inch forward facing step. The test stations were all located downstream of the step, the height of which was approximately one-half the smooth surface boundary layer thickness. Data were obtained at Mach Numbers of 2.0, 2.5, 3.0, and 3.5 and the test Reynolds Numbers, based on momentum thickness, ranged from 8,000 to 10,000 approximately. The results of this investigation indicate that the effect of the disturbance, produced by the step on the 'law of the wall' and 'velocity defect law' profiles appears to be negligible from a point approximately 10 flat plate boundary layer thicknesses downstream from the step. (Author)