A hybrid numerical flux scheme is proposed by adapting the carbunclefree modified Harten-Lax-van Leer contact(HLLCM) scheme to smoothly revert to the Harten-Lax-van Leer contact(HLLC) scheme in regions of shear. This ...A hybrid numerical flux scheme is proposed by adapting the carbunclefree modified Harten-Lax-van Leer contact(HLLCM) scheme to smoothly revert to the Harten-Lax-van Leer contact(HLLC) scheme in regions of shear. This hybrid scheme, referred to as the HLLCT scheme, employs a novel, velocity-based shear sensor. In contrast to the non-local pressure-based shock sensors often used in carbuncle cures, the proposed shear sensor can be computed in a localized manner meaning that the HLLCT scheme can be easily introduced into existing codes without having to implement additional data structures. Through numerical experiments, it is shown that the HLLCT scheme is able to resolve shear layers accurately without succumbing to the shock instability.展开更多
The present work concerns the numerical approximation of the M_(1) model for radiative transfer.The main purpose is to introduce an accurate finite volume method according to the nonlinear system of conservation laws ...The present work concerns the numerical approximation of the M_(1) model for radiative transfer.The main purpose is to introduce an accurate finite volume method according to the nonlinear system of conservation laws that governs this model.We propose to derive an HLLC method which preserves the stationary contact waves.To supplement this essential property,the method is proved to be robust and to preserve the physical admissible states.Next,a relevant asymptotic preserving correction is proposed in order to obtain a method which is able to deal with all the physical regimes.The relevance of the numerical procedure is exhibited thanks to numerical simulations of physical interest.展开更多
We propose a new characteristic-based finite volume scheme combined with the method of Central Weighted Essentially Non-Oscillatory （CWENO） reconstruction and characteristics, to solve shallow water equations. We ap...We propose a new characteristic-based finite volume scheme combined with the method of Central Weighted Essentially Non-Oscillatory （CWENO） reconstruction and characteristics, to solve shallow water equations. We apply the scheme to simulate dam-break problems. A number of challenging test cases are considered, such as large depth differences even wet/dry bed. The numerical solutions well agree with the analytical solutions. The results demonstrate the desired accuracy, high-resolution and robustness of the presented scheme.展开更多
在相对旋转坐标系下采用Harten,Lax and van Leer contact(HLLC)格式离散对流项,自行开发了基于多块结构化网格的有限体积程序,实现了对叶轮机械内部流场的数值求解.分别对半开式径向叶轮、闭式后弯叶轮展开数值模拟,程序和商业软件计...在相对旋转坐标系下采用Harten,Lax and van Leer contact(HLLC)格式离散对流项,自行开发了基于多块结构化网格的有限体积程序,实现了对叶轮机械内部流场的数值求解.分别对半开式径向叶轮、闭式后弯叶轮展开数值模拟,程序和商业软件计算得到的不同叶高处表面压力数据,其相对差异不超过1%,验证了算法的正确性.针对湍流方程的扩散项,分别使用完全离散和略去交叉导数项离散,通过对湍流黏度等值线、气动轴向力和力矩的比较表明:在网格正交性较好的情况下,略去交叉导数项的离散对计算结果的影响小于1%,显著地减小湍流方程离散的计算量.展开更多
基金the Singapore Ministry of Education AcRF Tier-2 Grant(No.MOE2014-T2-1-002)the Graduate Research Officer Scholarship from School of Mechanical and Aerospace Engineering,Nanyang Technological University,Singapore。
文摘A hybrid numerical flux scheme is proposed by adapting the carbunclefree modified Harten-Lax-van Leer contact(HLLCM) scheme to smoothly revert to the Harten-Lax-van Leer contact(HLLC) scheme in regions of shear. This hybrid scheme, referred to as the HLLCT scheme, employs a novel, velocity-based shear sensor. In contrast to the non-local pressure-based shock sensors often used in carbuncle cures, the proposed shear sensor can be computed in a localized manner meaning that the HLLCT scheme can be easily introduced into existing codes without having to implement additional data structures. Through numerical experiments, it is shown that the HLLCT scheme is able to resolve shear layers accurately without succumbing to the shock instability.
文摘The present work concerns the numerical approximation of the M_(1) model for radiative transfer.The main purpose is to introduce an accurate finite volume method according to the nonlinear system of conservation laws that governs this model.We propose to derive an HLLC method which preserves the stationary contact waves.To supplement this essential property,the method is proved to be robust and to preserve the physical admissible states.Next,a relevant asymptotic preserving correction is proposed in order to obtain a method which is able to deal with all the physical regimes.The relevance of the numerical procedure is exhibited thanks to numerical simulations of physical interest.
基金supported by the National Natural Science Foundation of China (Grant No.10771134)the Natural Science Foundation of Anhui Province (Grant No. 090416227)
文摘We propose a new characteristic-based finite volume scheme combined with the method of Central Weighted Essentially Non-Oscillatory （CWENO） reconstruction and characteristics, to solve shallow water equations. We apply the scheme to simulate dam-break problems. A number of challenging test cases are considered, such as large depth differences even wet/dry bed. The numerical solutions well agree with the analytical solutions. The results demonstrate the desired accuracy, high-resolution and robustness of the presented scheme.
文摘在相对旋转坐标系下采用Harten,Lax and van Leer contact(HLLC)格式离散对流项,自行开发了基于多块结构化网格的有限体积程序,实现了对叶轮机械内部流场的数值求解.分别对半开式径向叶轮、闭式后弯叶轮展开数值模拟,程序和商业软件计算得到的不同叶高处表面压力数据,其相对差异不超过1%,验证了算法的正确性.针对湍流方程的扩散项,分别使用完全离散和略去交叉导数项离散,通过对湍流黏度等值线、气动轴向力和力矩的比较表明:在网格正交性较好的情况下,略去交叉导数项的离散对计算结果的影响小于1%,显著地减小湍流方程离散的计算量.
