Reynolds-Averaged Simulation of Turbulent Flows with Immersed Boundaries

Simulating turbulent flows in complex real-life geometries faces two major problems.First, direct simulation of turbulent flow is extremely costly.Second, a complex geometry-conforming mesh is required, and such mesh presumably suffers from several mesh-quality related problems lowering the solution accuracy and prolonging the simulation time.To solve the first problem, phenomenological turbulence models based on, e.g.Reynolds-averaging, are commonly utilized.To address the second one, a variant of an immersed boundary (IB) method can be used where the complex geometry is projected onto a simple mesh by an indicator field and adjustment of governing equations.Consequently, a connection of Reynolds-averaging and an immersed boundary method shall resolve both the problems and provide a simulation approach favorable for e.g.optimizations.However, such a connection is not common.In this contribution, we utilize our custom IB variant, the hybrid fictitious domain-immersed boundary method (HFDIB) and aim on extending the HFDIB by tools of the Reynolds-averaged simulation (RAS).In comparison with standard simulation approaches, the new HFDIB-RAS approach shows acceptable results in wide range of flow Reynolds numbers and in several testing geometries.