Analysis of interface instabilities of separated gas-liquid two-phase flows with conservative two-fluid model

A numerical study is conducted in order to simulate separated two-phase flows of gas-liquid with conservative two-fluid model. Firstly, different numerical methods are examined to investigate the flow characteristics and stability of equations. The shock-capturing method is developed to an algorithm scripted in Fortran; and the force method is selected due to the higher accuracy. For validation of the simulations, instability range is compared to the calculations using the classic Kelvin-Helmholtz instability (KHI) equation. The wave growth was examined in a pipe and were compared with previous articles. The instability range of this research covers the classic KHI equation for the long wavelength with small amplitude. Results reveal that when the wavelengths are reduced, KHI range is not consistent, and wavelength effects on instability and KHI range is over predicted. This study presents a modified numerical method that improved the consistency with the analytical solution in comparison with other prior researchers' codes.