ADAPTIVE FINITE-VOLUME UPWIND APPROACHES FOR AEROACOUSTIC COMPUTATIONS

The solution-adaptive cell-vertex finite volume upwind approaches on q uadrilateral-triangular meshes are presented to solve the unsteady Eul er equations. For the present approaches, Runge-Kutta time-integration method, Roe's Riemann solver, a modified area-averaged approach, the MUSCL differencing with two kinds of characteristic interpolation vari ables, and an improved solution-adaptive technique, where a new mesh-e nrichment indicator for acoustic wave is developed, are included, To e valuate the present approaches, Ringleb's flow, transonic flow around the NACA 0012 airfoil, shock propagation in a channel, traveling vorte x in a freestream, and an acoustic pulse in a freestream are investiga ted. In the comparisons of present numerical results with related exac t and/or other numerical solutions, it is shown that the upwind approa ch with the second kind of characteristic variables is accurate and ef ficient, and the present adaptive technique with appropriate mesh-enri chment indicators enhances this upwind approach to capture the shock w ave, vortex, and acoustic wave, By using this solution-adaptive approa ch to solve the vortex-shock interaction and transonic blade-vortex in teraction problems, the flow phenomena and aeroacoustic behaviors are simulated.