Construction of conservative finite difference schemes suitable for simulations of turbulent flows with complicated geometry and application to wind turbine aerodynamics

摘要

In order to conduct direct numerical simulation (DNS) or large eddy simulation (LES) of turbulent flows with complicated geometry, we have to use accurate finite difference methods in generalized curvilinear coordinate system. In this report, finite difference schemes (FDSs) in generalized curvilinear coordinate system suitable for simulations of incompressible turbulent flow are constructed by relatively simple extension of the proper finite difference schemes derived in equidistant Cartesian coordinate system. Preliminary tests by DNSs of a plane channel flow reveal that the mesh dependency such as non-orthogonality and non-uniformity on results is reduced by the present FDS. As application of the FDS to wind turbine aerodynamics, large eddy simulations of flow fields around a circular cylinder and an airfoil section for wind turbines are simulated using HITACHI SR8000 supercomputer installed at the Tsukuba Advanced Computing Center (TACC) of Agency of Industrial Science and Technology (AIST). The formation of laminar separation bubbles with reverse flow region on wind turbine blades are successfully reproduced in our simulation.