虚拟流体方法的设计原则

研究模拟可压缩多介质流的虚拟流体方法，建立一般状态方程下定义虚拟流体状态的基本原则.根据波系结构和使用的自由变量分别推导虚拟流体状态的定义方式.结果表明在这些方式下求解多介质Riemann问题理论上完全精确.进一步总结几种简单有效的虚拟流体方法，这些定义方式不依赖于虚拟流体区域可能产生的波系结构.其中一种类似于反射边界条件，只是界面速度需要首先精确预测出来.数值算例验证了研究结果的合理性.

Design Principles of Ghost Fluid Method

By analyzing ghost fluid method for compressible multi-medium flows, fundamentals for defining ghost fluid state with a general equation of state are described. All possible definitions of ghost fluid states are derived according to wave patterns and free variables in ghost fluid region. Following these treatments, it reveals that solution of multi-medium Riemann problem can be obtained exactly in theory. Several simple but effective definitions independent with wave patterns in ghost fluid region, are further summarized. One of these ways is similar to reflective boundary condition. An essential prerequisite is that interfacial velocity must be predicted exactly. Numerical results show that this methodology indeed works reasonably for multi-medium flows.