UPWIND FINITE-VOLUME NAVIER-STOKES COMPUTATIONS ON UNSTRUCTURED TRIANGULAR MESHES

A Navier-Stokes solver using upwind finite-volume method on unstructured triangular meshes is developed and tested. A Godunov-type upwind method is used for inviscid flux computations. An accurate linear reconstruction is used to compute the two Riemann states at the cell face, and Roe's approximate Riemann solver is solved for inviscid fluxes. A finite-volume formulation for the viscous terms, which can be second-order accurate for a large class of triangular cells, is developed and tested. The algebraic Baldwin-Lomax turbulence model is implemented vis the use of a turbulence reference grid, the only purpose of which is to provide necessary length scales to the model. All of the turbulence computations are done on the unstructured main mesh without interpolation to and from the reference grid. An approximate lower-upper factorization scheme is used for implicit time integration. Various low and high Reynolds number flows are computed to verify the proposed scheme, including a high Reynolds number flow over a two-element airfoil.