Immersed body-fitted meshes boundary method

An immersed boundary method combined with overset meshes on surface was proposed to simulate three-dimensional viscous compressible flow. Orthogonal Cartesian meshes were adopted to simulate the mainstream, and the body-fitted meshes immersed in the Cartesian meshes were adopted to simulate the viscous flow near the surface. The flow field information of the overlapped regions was transmitted to each other through spatial interpolation. The advantages of the immersed body-fitted meshes boundary method were summarized. Strategies for finding contribution units and interpolating flow information were introduced in detail. The Navier-Stokes equations with Spalart-Allmaras turbulence model were used to solve the flow field. The convection terms were discretized by flow vector splitting method and 5th order WENO (weighted essentially non-Oscillatory)-Z scheme, while the viscosity terms were discretized by 6th order central difference scheme. The time term was discretized by Runge Kutta explicit scheme. The numerical verification showed that spatial precision of this method was at least 4th order. This method is suitable for the unsteady flow simulation of moving rigid meshes without the need to update the mesh shape. The equidistant surface body-fitted meshes generation process is simple enough to avoid the tedious manual adjustment process. Combined with the Cartesian meshes, it can provide sufficient mesh density near the wall and effectively reduce the total mesh number demand. © 2021, Editorial Department of Journal of Aerospace Power. All right reserved.