Annual Research Briefs 1999

This work deals with the numerical simulation of turbulent boundary layer flows past a 25-degree, asymmetric trailing edge of a model airfoil, investigated experi-mentally by Blake (1975). The Reynolds number based on free-stream velocity U1 and the airfoil chord C is 2:15 106. The objective is to develop eective numeri-cal prediction methods, based on a combination of large-eddy simulation (LES) and Lighthill’s acoustic analogy, for trailing-edge noise and surface pressure fluctuations. A major diculty encountered in previous studies (Wang 1998, Wang & Moin 1999) is the high computational cost of the source-eld simulation given the rela-tively high Reynolds number and complex geometry. More than 200 single processor CPU hours were needed on CRAY C-90 to advance the simulation by one flow-through time even though the computational domain contained only the rear 38% of the model airfoil chord and the near wake of approximately equal length. The spanwise domain width is only 50 % of the airfoil thickness, which is too restrictive to allow the development of fully three-dimensional flow structures in the separated region near the trailing edge. As a result, while this computational domain is ade