Using Large Eddy Simulations to Predict Fluctuating Wall Pressure Caused by Turbulent Flow over Rough Surfaces

摘要

The large eddy simulation (LES) framework in the AcousticFOAM suite of flow simulation software has been traditionally used to predict fluctuating wall pressures caused by turbulent flow over smooth, rigid surfaces. The fluctuating wall pressure is then used to characterize the acoustic source field. In reality, of course, surfaces are rarely hydrodynamically smooth, and can be quite rough as when, for example, flow occurs over surfaces roughened by irregular roughness. The spectrum of fluctuating wall pressure associated with turbulent flow over surface roughness can be significantly different from that associated with turbulent flow over a smooth surface. Accordingly, the LES formulation in AcousticFOAM has been modified to account for the effects of surface roughness. This modification is in the form of the dynamic sub-grid-scale surface roughness model developed by Anderson and Meneveau (2011). To account for the dipole nature of sound radiated from surface roughness, the spectral formulation of Glegg and Devenport (2009) for sound radiated from rough surfaces has also been used to calculate far-field sound spectrum.