Computations of transonic flow with the v(2)-f turbulence model

The nu (2)-f (or k-epsilon-nu (2)) model of Durbin, which has shown very go od performance in several test cases with separated flows at low speeds, ha s been applied to transonic flows over the Delery bump and the RAE 2822 air foil. In both cases, shock-induced separation occurs. The elliptic relaxati on equation of the model is used in the entire computational domain, i.e., it is computed in both the subsonic and supersonic regimes. The predicted s ize of the separation zone, surface pressures and mean Velocities by two mo del variants agree reasonably well with the experimental data. Consistent w ith our earlier investigation, in which the nu (2)-f model was applied to a subsonic high-lift airfoil at a high incidence angle, the level of turbule nt shear-stress within the separation zone is underestimated. A 'code-frien dly' variant of the model is proposed to enhance numerical stability. It ha s proven to be advantageous if an implicit segregated equation-by-equation approach is used. This modification alleviates the 'stiffness problem' asso ciated with the original model caused by the boundary conditions at walls. This is particularly true when the Reynolds number is high and the near-wal l grid spacing is extremely small. (C) 2001 Elsevier Science Inc. All right s reserved.