Applicability of High-Order Upwind Difference Methods to the Two-Fluid Model

Numerical stability of the two-fluid model when the high-order upwind difference method is applied was systematically clarified using a single linear model equation. The results of the examination were verified using an actual two-fluid model. It was confirmed that the high-order methods tend to yield unstable numerical solutions compared with the first-order upwind difference method, and the method which includes an explicit diffusion term in a basic equation was proposed in order to conduct numerically stable calculation with the high-order method. It was also demonstrated by calculating a faucet flow problem that the high-order method gives a more accurate numerical solution than the first-order method.