(307a) An Overview of the Stress-Blended Eddy Simulation Method in Ansys CFD (Invited Talk)

While RANS turbulence models are still employed in the majority of CFD simulations, there are numerous industrial applications, where the accuracy provided by RANS models is not sufficient for capturing the essential dynamics of the flow physics. In such scenarios, more CPU-intensive Scale-Resolving Simulation (SRS) techniques need to be employed. The classical Large Eddy Simulation (LES) approach was historically very successful in the prediction of free shear flows and free mixing zones, as the largest scales in these regions can be resolved with available CPU power. However, LES is extremely costly and in most cases unrealistic, when the solution of wall bounded flows is required - as is the case e.g. if wall heat transfer is of interest. In applications which involve both, large free mixing zones and wall boundary layers, as is the case in many chemical reacting flows, hybrid RANS-LES methods offer a good balance of accuracy versus cost. The most prominent hybrid method is the Detached Eddy Simulation (DES) family. Since the introduction of DES, numerous deficiencies of this approach have become apparent and more advanced methods have been developed. At ANSYS, the approach followed is termed Stress-Blended Eddy Simulation (SBES). It consists of a direct blend of existing RANS and LES models using built-in blending functions. The principle concept of SBES will be discussed and its advantages over DES and similar methods will be demonstrated for a wide range of flow applications. A comparison of computing costs of DES versus SBES will conclude the presentation.