Theoretical Pressure Correlation Functions in Turbulent Boundary Layers
AEROSPACE CORP EL SEGUNDO CA IVAN A GETTING LABS
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A Poisson equation is constructed for the pressure in terms of velocity fluctuations, and solved. The pressure correlation has a second-order velocity fluctuation contribution usually assumed dominant in past work and a fourth-order velocity correlation contribution. The velocity correlations are assumed to be those--suitably weighted--found from homogeneous turbulence measurements. Results are computed for two boundary layers an idealized canonical turbulent boundary layer and a deliberately thickened boundary layer. The pressure variances are found to be essentially the same as measured values. The correlations have scales equal to the displacement thickness of the boundary layer. All correlations are positive except the streamwise, x- correlation for the thickened boundary layer. The canonical layer shows a pressure variance that peaks very close to the wall, near the laminar sublayer. The fourth-order velocity fluctuations may be generally neglected for the thickened boundary layer close to the wall it is an important part of the variance and correlation for the canonical layer.
- Fluid Mechanics