Application of a 3D RANS solver on the complex hill of Bolund and assessment of the wind flow predictions

A 3D Reynolds-averaged Navier–Stokes solver, CRES–flowNS, is used in this paper for the flow simulation of four flow cases established during the Bolund hill experiment. CRES–flowNS, which has been developed at CRES, solves the steady state, incompressible Navier–Stokes equations on a curvilinear grid, employing k–ω turbulence closure. By generating alternative meshes, grid independent results are achieved that are compared to measured wind speed and turbulence characteristics in the four flow cases. From a methodological point of view, the scope of the present paper is to illustrate the appropriate numerical steps in order to assure reliable atmospheric flow predictions in complex terrain.

► Flow around the complex hill of Bolund is simulated with a 3D RANS solver.
► Grid independent results are possible if the appropriate numerical steps are taken.
► Two-equation turbulence models provide reliable results in complex terrain flows.
► Restrictions regarding the flow prediction appear in the regions of escarpments.