A Viscoelastic Turbulence Model Based on Renormalization Group Theory

The aim of this project, which is in cooperation with DaimlerChrysler AG, Rhodia Acetow AG, the Steinbeis transfer center HTCO and Prof. H.Kielhoefer at the University of Augsburg, is to improve the numerical simulation of turbulent separated flows. Flows of that type arise in a variety of technically important situations. An example from automotive industry is the flow behind a car. By means of the renormalization group theory (RNG), we have constructed a Reynolds stress model with model coefficients calculated from theory. A first version of our turbulence model has been tested with the aid of the finite element code FIDAP with encouraging results for the flow over a backward facing step. Within this project, we have also addressed some more theoretical aspects, ranging from questions regarding the “epsilon expansion” up to the question of existence and regularity of solutions of the stochastically forced Navier Stokes equation. The latter work, which will be essential for a mathematically rigorous foundation of our model, has been done by Dipl.-Math. Ch. Gugg at the University of Augsburg. The ultimate test case for our model shall be the flow behind a car with data from wind tunnel experiments provided by the DaimlerChrysler AG.