A new class of second order accuracy semidiscrete difference schemes is presented for the two-dimensional nonlinear scalar hyperbolic conservation laws. It is based on flux splitting, piecewise linear cell-averaged re...A new class of second order accuracy semidiscrete difference schemes is presented for the two-dimensional nonlinear scalar hyperbolic conservation laws. It is based on flux splitting, piecewise linear cell-averaged reconstruction and upwind property in the spatial discretization. By using TVD Runge-Kutta time discretization method, the full discrete scheme is obtained and its MmB property is proved. The extension to the two-dimensionalnonlinear hyperbolic conservation law systems is straightforward by using component-wise manner. The main advantage is simple: no Riemann problem is solved, and so field-by-field decomposition is avoided and the complicated computation is reduced. Numerical results of two-dimensional Euler equations of compressible gas dynamics verify the accuracy and robustness of the method.展开更多
Numerical solutions of Riemann problems for 2-D scalar conservation law are given by a second order accurate MmB (locally Maximum-minimum Bounds preserving) scheme which is non-splitting. The numerical computations s...Numerical solutions of Riemann problems for 2-D scalar conservation law are given by a second order accurate MmB (locally Maximum-minimum Bounds preserving) scheme which is non-splitting. The numerical computations show that the scheme has high resolution and non-oscillatory properties. The results are completely in accordance with the theoretical solutions and all cases are distinguished efficiently展开更多
In this paper, a new Riemann-solver-free class of difference schemes are const ructed to 2-D scalar nonlinear hyperbolic conservation laws. We proved thatthese schemes had second order accurate in space and time, and ...In this paper, a new Riemann-solver-free class of difference schemes are const ructed to 2-D scalar nonlinear hyperbolic conservation laws. We proved thatthese schemes had second order accurate in space and time, and satisfied MmB properties under the appropriate CFL limitation. Moreover, these schemes hadbeen extended to systems of 2-D conservation laws. Finally, several numericalexperients show that the performance of these schemes are quite satisfactory.展开更多
Front Tracking algorithms have generally assumed that the computational medium is divided into piece-wise smooth subdomains bounded by interfaces and that strong wave interactions are solved via Riemann solutions. How...Front Tracking algorithms have generally assumed that the computational medium is divided into piece-wise smooth subdomains bounded by interfaces and that strong wave interactions are solved via Riemann solutions. However , in multidimensional cases, the Riemann solution of multiple shock wave interactions are far more complicated and still subject to analytical study. For this reason ,it is very desirable to be able to track contact discontinuities only. In this paper , we describe a new numerical algorithm to couple a tracked contact surface and an un tracked strong shock wave. The new tracking algorithm reduces the complication of computation , and maintains the sharp resolution of the contact surface. The numerical results are in good agreement.展开更多
In this paper, the phenomena of spirals are numerically presented by MmB scheme [1] for initial value problems of 2-D gas dynamics (gamma = 1.4), which include 2-D Riemann problems and continuous initial value problem...In this paper, the phenomena of spirals are numerically presented by MmB scheme [1] for initial value problems of 2-D gas dynamics (gamma = 1.4), which include 2-D Riemann problems and continuous initial value problems. The numerical results are well coincide with on the exact solution in [2] and the conjectures on solution structure in [3] for 2-D isentropic and adiabatic flows. In isentropic flow, for high speed rotation (v(0)/c(0) > root 2), there is a region of vacuum at the origin and for low speed rotation (v(0)/c(0) < root 2), there is no vacuum, and for adiabatic flow, the structure of spirals is also discussed.展开更多
The Riemann problem for two-dimensional flow of polytropic gas with three constant initial data is considered. Under the assumption that each interface of initial data outside of the origin projects exactly one plana...The Riemann problem for two-dimensional flow of polytropic gas with three constant initial data is considered. Under the assumption that each interface of initial data outside of the origin projects exactly one planar wave of shock, rarefaction wave or contact discontinuity, it is proved that only two kinds of combinations, JRS and Js, are reasonable. Numerical solutions are obtained by using a nonsplitting second order accurate MmB Scheme, and they efficiently reflect the complicated configurations and the geometric structure of solutions of gas dynamics system. (Author abstract) 10 Refs.展开更多
文摘A new class of second order accuracy semidiscrete difference schemes is presented for the two-dimensional nonlinear scalar hyperbolic conservation laws. It is based on flux splitting, piecewise linear cell-averaged reconstruction and upwind property in the spatial discretization. By using TVD Runge-Kutta time discretization method, the full discrete scheme is obtained and its MmB property is proved. The extension to the two-dimensionalnonlinear hyperbolic conservation law systems is straightforward by using component-wise manner. The main advantage is simple: no Riemann problem is solved, and so field-by-field decomposition is avoided and the complicated computation is reduced. Numerical results of two-dimensional Euler equations of compressible gas dynamics verify the accuracy and robustness of the method.
文摘Numerical solutions of Riemann problems for 2-D scalar conservation law are given by a second order accurate MmB (locally Maximum-minimum Bounds preserving) scheme which is non-splitting. The numerical computations show that the scheme has high resolution and non-oscillatory properties. The results are completely in accordance with the theoretical solutions and all cases are distinguished efficiently
文摘In this paper, a new Riemann-solver-free class of difference schemes are const ructed to 2-D scalar nonlinear hyperbolic conservation laws. We proved thatthese schemes had second order accurate in space and time, and satisfied MmB properties under the appropriate CFL limitation. Moreover, these schemes hadbeen extended to systems of 2-D conservation laws. Finally, several numericalexperients show that the performance of these schemes are quite satisfactory.
文摘Front Tracking algorithms have generally assumed that the computational medium is divided into piece-wise smooth subdomains bounded by interfaces and that strong wave interactions are solved via Riemann solutions. However , in multidimensional cases, the Riemann solution of multiple shock wave interactions are far more complicated and still subject to analytical study. For this reason ,it is very desirable to be able to track contact discontinuities only. In this paper , we describe a new numerical algorithm to couple a tracked contact surface and an un tracked strong shock wave. The new tracking algorithm reduces the complication of computation , and maintains the sharp resolution of the contact surface. The numerical results are in good agreement.
文摘In this paper, the phenomena of spirals are numerically presented by MmB scheme [1] for initial value problems of 2-D gas dynamics (gamma = 1.4), which include 2-D Riemann problems and continuous initial value problems. The numerical results are well coincide with on the exact solution in [2] and the conjectures on solution structure in [3] for 2-D isentropic and adiabatic flows. In isentropic flow, for high speed rotation (v(0)/c(0) > root 2), there is a region of vacuum at the origin and for low speed rotation (v(0)/c(0) < root 2), there is no vacuum, and for adiabatic flow, the structure of spirals is also discussed.
文摘The Riemann problem for two-dimensional flow of polytropic gas with three constant initial data is considered. Under the assumption that each interface of initial data outside of the origin projects exactly one planar wave of shock, rarefaction wave or contact discontinuity, it is proved that only two kinds of combinations, JRS and Js, are reasonable. Numerical solutions are obtained by using a nonsplitting second order accurate MmB Scheme, and they efficiently reflect the complicated configurations and the geometric structure of solutions of gas dynamics system. (Author abstract) 10 Refs.
