Abstr:Flow over an isolated hill (without dispersion)
Underlying Flow Regime 3-13
The flow separation behind a smooth hill is the logical extension to the most widespread and basic CFD test case of the backstep-flow. It allows testing of body-fitted or unstructured discretisations, and from the turbulence modelling point of view, it adds the difficulty of predicting the point of flow separation, as this one is no longer imposed by a geometrical singularity. Obtaining the correct length of recirculation, or re-attachment point, is further complicated by the fact that this strongly depends on the separation point position and resulting angle of the separating streamline. The case is not only very relevant to the environmental sector but also to all areas in need of refined modelling of fully developed turbulent flows, and in a nutshell, it exhibits the severe limitations of standard RANS models for separated flows.
Contributors: Frederic Archambeau - EDF - R&D Division