Sensitivities in Large Eddy Simulation and Improved Estimates of Turbulent Flow Functionals

Abstract

We consider a prototypical problem: simulate velocity and pressure in a turbulent flow using large eddy simulation (LES) and then use the results to estimate the force that the underlying turbulent flow exerts on an immersed body. For eddy viscosity-type LES models we develop the appropriate continuous sensitivity equation and show how it can improve the functional estimate by using the sensitivity with respect to the user-selected length scale to incorporate the effects of the underlying unresolved small-scale fluctuations on the functionals sought.