Development And Preliminary Comparison Of Gas Flow Field Program Using Different Schemes

The finite volume method Roe scheme,AUSM+ scheme and upwind NND scheme are studied in this thesis,and the gas flow field simulation program containing three kinds of schemes is compiled,the characteristics of the three kinds of calculation of schemes are compared and analyzed through flow field examples.According to the requirement of the finite volume method,the clock structure grid in the Descartes coordinate system is generated.The grid generation program module is written in the order of dividing computation domain block,lattice grid generation,grid generation and grid splicing,the preparation of the flow field caculation is completed.In the process of programming the solver,the solution method is chosen acoording to the caculation cinditions and requirements,and the modular programming method is adopted,various methods are used as different modular of the program.The patial discrete scheme contains Roe scheme,AUSM+ scheme and NND scheme.At the same time,the two order MUSCL is used to improve the spatial sccuracy.The viscosity flux processing adopts the central difference scheme,the time propulsion scheme sdopts the three order explicit Runge-Kutta method,and the boundary condition processing is mainly processed through virtual grid,the turbulence model is the standard k-? model.Numerical similation of the flow field is carried out by using the calculation program written in the paper.By calculating the example of the front step flow field and compared with the literature results,the correctness of the program has been proved.Then the flow field in the nozzle,the free jet flow field and the flow field of the slanted plate with gas jet impingement are simulated,and the differences between the three schemes are compared and analyzed.The three schemes can all correctly simulate the flow characteristics of the field and show a well shock capture ability.The Roe scheme has a high stability.The dissipation factor is a matrix,so the numerical dissipation is larger and the flow field fluctuates faster.The AUSM+ scheme shows numerical oscillation near the wall because of its dissipation factor is a scalar.In the process of flow,the dissipation of the flow is samller and the attenuation of the flow field is slow.The upwind NND scheme is similar to the Roe scheme,and the numerical oscillation is easy to occur at the exit boundary.The upwind NND scheme is less used in the calculation of gas flow field.This paper proves the feasibility of numerical simulation of gas flow field,and increases the type of alternative calculattion scheme in the numerical simulation of gas flow field.