engleski

A compressible pressure-based finite-volume method for homogenous two-phase mixtures including multiple gas species

A compressible multi-phase flow solver has been developed with the goal of simulating naval hydrodynamics problems associated with underwater explosions (UNDEX) and gas-launched projectiles and missiles. The formulation utilizes a pressure-based PISO-type finite-volume algorithm for two-phase mixtures, including multiple gas species, and is implemented using the OpenFOAM CFD Toolbox. A volume-of-fluid (VOF) approach is used to model the fluid-fluid interfaces, and we adopt an isentropic ideal-gas equation-of-state for the gas phase and assume a constant speed-of-sound in the liquid phase. Since we are interested in applications where more than one gaseous species can be present, we introduce mass-balance equations which enable the tracking of each species. In the ICNMMF presentation, we will review the derivation of the mathematical model and the implementation using the OpenFOAM libraries. We will present results from basic test cases and UNDEX applications. For example, Figure 1 shows pressure contours at time = 1.1ms from an UNDEX simulation under a flat plate. Comparison to Kadioglu and Sussman (2008) show that our solver is predicting similar results to their high-fidelity nested-mesh approach. Figure 2 shows an UNDEX simulation near an ocean air-water interface, and demonstrates three- dimensional simulation of a multi-species problem where the gas phase consists of air and UNDEX gas. In addition, the simulation demonstrates the ability to model the large-scale free- surface disturbance caused by the violent underwater bubble growth-and-collapse process. To conclude the presentation, we will summarize some of the key challenges in the mathematical and numerical formulation of our solver, and provide ideas on resolving these issues in future work.

CFD; OpenFOAM; volume of fluid

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