VI Summary of Experience with Hybrid RANS-LES Methods and a Look Ahead

Abstract

With the core activity on the development of CFD tools for aerospace applications, and the growing part of activities also oriented towards the area of fluid dynamics for industrial systems, all so-called “real-world” applications exhibit complex flow phenomena such as unsteady flow, (massive) separation, transition to turbulence and turbulence itself. All theses applications, exhibiting massive flow separation, need ideally the use of advanced turbulence models so as to capture the correct separation pattern and to resolve the frequency content of at least the mean flow. This is underlined by all test cases that have been carried out and properly investigated – see Chapter IV - during the course of the DESider project, and which at the same time allow to gain a good understanding of the pro and con’s of the methods used and the way they interact with the numerical algorithms, but also with the grid properties and their effects on the computational effort required to attain satisfactory results. In general, the outcome can be taken as means for best practice guidelines and information on the accuracy of the numerical results, their cost and, thus, the area of applications for which these new methods should be considered.