Large Eddy Simulation of Flows of Engineering Interest: A Review

Abstract

The deeper insights of relationships between large and small scales lead to the development of large eddy simulation (LES), where large scales are explicitly resolved and small scales being universal are modeled. With the advent of high computing power, it is feasible now to successfully simulate the complex turbulent flows of engineering interest using LES. The paper starts with a brief discussion on features of turbulence leading to LES and subgrid-scale models. The evaluation of LES to resolve the physics of transitional and turbulent flows are made based on illustrations, where the few being previous studies of the author and his research group. Although results demonstrate an immense potential of LES to simulate the transitional and turbulent flows as an alternative to DNS with moderate computational cost, there exist several bottlenecks even today. The requirement of very fine meshes near walls is one of such bottlenecks in using LES at high Reynolds number flows. The hybrid LES-RANS, which was invented to eliminate the limitations, is also discussed here in brief. As a concluding remark, it can be stated that the method is particularly suitable and superior to RANS for situations, where unsteadiness and large-scale structures dominate the flow.