On the limiters of two-equation turbulence models

Abstract

When two-equation turbulence models are used, unrealistically large values of turbulence variables can appear due to the infringement of a realizability condition or to numerical error. To cure this in practical calculations, various limiters on the source terms are often employed. In the present work, a mathematically correct bound for eddy viscosity is obtained from the realizability condition itself. From this, realizability bounds for several terms of model equations are given. The effects of various bounds including the present one, are investigated on the predictions of fundamental flows including simple shear flows, supersonic compression ramp flow and supersonic base flow. It is shown that the limiter affects the prediction very significantly.