Leading edge vortex flow computations and comparison with DNW-HST wind tunnel data

Abstract

Computations are presented for the vortical flow around a sharp-edged cropped delta wing with 65° leading edge sweep using a computational method based on the Reynolds-averaged Navier-Stokes equations. It is demonstrated that turbulence modelling plays a crucial role in the ability to capture the vortical structures. Standard one- and two-equation turbulence models need corrections for vortical flows in order to avoid over-prediction of the levels of turbulent viscosity inside vortex cores. In this paper two types of modifications to the two-equation k-omega turbulence model are investigated to overcome this problem. One modification consists of limiting the production of turbulent kinetic energy in the A:-equation, whereas the other modification is aimed at increasing the production of dissipation in the dissipation equation (omega equation); omega represents the dissipation of turbulent kinetic energy. The computational results at the conditions M00 = 0.85,a = 10°,and ReCr = 9x10^6, are compared with detailed experimental surface and field data obtained from a series of wind tunnel tests in the DNW-HST at NLR. The comparisons show that the modification which increases the production term for the dissipation rate of turbulent kinetic energy in the omega-equation produces the best results when it comes to capturing the vortex core in a realistic way. The proposed modification is in line with other approaches found in the literature for one-equation turbulence models. Paper presented at the RTO/AVT Symposium on "Vortex Flows and High Angle of Attack", Loen, Norway, 7-11 May 2001.