Embedded DDES of 2D Hump Flow

The present work aims to investigate the usage of embedded regions of turbulent flow simulation near to the point of separation; towards an approach whereby discrete regions of turbulent resolving techniques are used within a domain predominantly solved using the RANS equations. The common Delayed Detached Eddy Simulation (DDES) approach is here used to compute the flow around a 2D hump centred within a ‘full domain’ i.e. also incorporating an upstream section. Subsequently the domain length is reduced and the flow is started at two locations close to the separation point by means of unsteady turbulent inlet conditions. The Divergence Free Synthetic Eddy Method (DF-SEM) and its predecessor are tested for their ability to reproduce the original DDES results from the full domain. In the present case we aim to return a minimal disturbance from the full domain solution and thus herein we do not focus on the predictive accuracy of the selected DDES approach. The motivation for this technique is to provide guidance for the optimal reduction of embedded regions of turbulent simulation in complex applications; i.e. including multiple instances of separated flow. Some comments regarding computational expense of the method are also provided.