The Research On Parallel Algorithm Of N-S Equations And Its Applications In The Flowfield Of Projectiles

With the increasingly development of Computational Fluid Dynamics (CFD), Numerical simulation plays important parts in engineering applications. To some numerical simulations of viscous fluid of complex geometry, higher memory and computing speed are needed. It is hard to simulate the flowfield of complex vehicle only by improving the computer performance of single computer and serial calculation technology, parallel computing has been the only method to improve the computing efficiency, which is the current CFD technology trend. So the investigation of parallel algorithm is important. The main aim of the paper is to study the parallel algorithm of Navier-Stokes equations, using MPI (Message Passing Interface) standard library on PC-CLUSTER that is distributed memory architecture, in order to develop a suit of highly universal parallel computing software. The following works had been performed:First of all, the generation of viscous structured grids is discussed. In order to simulate viscous flowfield correctly, patched grid method is used to generate viscous grids. In the paper, different topology design methods of some mixed type grids are discussed and some representative viscous grid examples are given.Secondly, the numerical methods are discussed. The steady compressible equations are solved using the finite volume method in spatial discretization and Van Leer+AUSM flux splitting scheme, which is developed to calculate the convection flux, has excellent shock capturing capacity, and the viscous flux is calculate by central finite volume scheme. Local time step is used to accelerate the convergence during the five Runge-Kutta. In the simulation of turbulence flows, Spalart-Allmaras one-eqution turbulence model is implemented to evaluate the turbulent viscosity.Then, the distributed memory parallel computation strategy based on the serial code is studied. Physics-region-partition is proposed in the parallel algorithm design. This paper starts with parallel algorithm design, using Single-Program-Multip-Data model and MPI standard library as a way of data communication, in order to prove the correctness of parallel algorithm and make the code more robust.Finally, applications of the parallel algorithm above are studied by numerical simulating the flowfield of projectiles. Numerical results indicate that a good parallel performance is achived, some related aerodynamics data is correctly given.