Comparison of the Wall Pressure Fluctuations in Artificially Generated Turbulent Spots, Natural Transition and Turbulent Boundary Layers.
NAVAL OCEAN SYSTEMS CENTER SAN DIEGO CA
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Experiments have been conducted to measure the wall pressure fluctuations associated with artificially generated turbulent spots in a laminar boundary layer. The results show that both the rms wall pressure and the wall pressure spectra of turbulent spots are influenced by the local mean flow pressure gradient. The zero and favorable pressure gradient wall pressure data are in agreement with turbulent boundary layer results. However, the current spot data shows that, in the presence of an adverse pressure gradient, the spots rms wall pressure is approximately 1.5-2.5 times larger than that found for the zero and favorable pressure gradient cases. These results are in general agreement with the adverse pressure gradient data of Huang and Hannan 1975. Additionally, the nearly constant magnitude of the spots adverse pressure gradient wall pressure spectrum indicates a nearly even distributions of energy with frequency. Keywords Turbulent boundary layer, Laminar boundary layer, Wall pressure fluctuations.
- Fluid Mechanics