1 Department of Wind Energy, Technical University of Denmark2 Fluid Mechanics, Department of Wind Energy, Technical University of Denmark3 Aeroelastic Design, Department of Wind Energy, Technical University of Denmark4 Department of Mechanical Engineering, Technical University of Denmark
Nowadays collocated grid based CFD methods are one of the most e_cient tools for computations of the ows past wind turbines. To ensure the robustness of the methods they require special attention to the well-known problem of pressure-velocity coupling. Many commercial codes to ensure the pressure-velocity coupling on collocated grids use the so-called momentum interpolation method of Rhie and Chow . As known, the method and some of its widely spread modi_cations result in solutions, which are dependent of time step at convergence. In this paper the magnitude of the dependence is shown to contribute about 0.5% into the total error in a typical turbulent ow computation. Nevertheless if coarse grids are used, the standard interpolation methods result in much higher non-consistent behavior. To overcome the problem, a recently developed interpolation method, which is independent of time step, is used. It is shown that in comparison to other time step independent method, the method may enhance the convergence rate of the SIMPLEC algorithm up to 25 %. The method is veri_ed using turbulent ow computations around a NACA 64618 airfoil and the roll-up of a shear layer, which may appear in wind turbine wake.
Journal of Physics: Conference Series (online), 2014, Vol 524
Main Research Area:
5th International Conference on The Science of Making Torque from Wind 2014European Academy of Wind Energy : The Science of Making Torque from Wind