Direct Numerical Simulation of Flow over a bump

Abstract

The mechanism of wall turbulence is an important issue from a theoretical and modelling aspect. All existing models of the near wall region of turbulent flows are still empirical and even the most sophisticated are not very successful in adverse pressure gradient situations. The improvements of models require reliable data of turbulent flows. The present project meet one of the objective of the European project WALLTURB which is to build a database of wall bounded turbulent flows with and without adverse pressure gradient. Taking the advantage of the DEISA Extreme Computing Initiative (DECI) project, a Direct Numerical Simulation (DNS) of a channel flow over a curved surface will be performed at high Reynolds number Ret=600 at the inlet). Some DNS of zero pressure gradient channel flow are already available at high Reynolds, but only few DNS of adverse pressure gradient flows have been performed. The numerical code which will be used in this project keeps the accuracy and efficiency of a spectral code by introducing a mapping in the equations. The database generated by the DNS will be shared in the research community and will be helpful to increase the knowledge on wall turbulence and flow separation and to improve turbulence models. These are important issues for the simulation of more complex and realistic turbulent flows.