Structure of a compressible boundary layer over a curved wall
Conference Paper
Overview
Overview
abstract
1997, American Institute of Aeronautics and Astronautics, Inc. An experimental analysis of a supersonic turbulent boundary layer distorted by streamwise pressure gradients was performed using particle image velocimetry (PIV) and hot-film anemometry. Four pressure gradients were examined; a zero pressure gradient (M = 2.8), a favorable pressure gradient (M = 3.0) an adverse pressure gradient (M = 2.7), and a combined pressure gradient (M = 2.5). Measurements included mean velocity, velocity turbulence intensity, mass flux turbulence intensity and energy spectra. Instantaneous (10 nsec) Mie scattering flow visualizations were also acquired. Qualitatively, the flow visualizations indicated that the turbulent flow structures were strongly affected by the pressure gradients. The PIV contours and the hot-wire profiles indicated that the boundary layer thickness increased 40% and decreased 30%, as compared to the zero pressure gradient, for the favorable and adverse pressure gradients, respectively. Further, the PIV and hot-wire data indicated that the axial turbulence intensity levels increased 22% for the adverse pressure gradient and combined pressure gradient, and decreased 25% for the favorable pressure gradient as compared to the zero pressure gradient. The energy spectra data indicated the pressure gradient (favorable or adverse) increased the energy transfer to the higher frequencies.
