The interaction of the shock wave with the bubble and the effect of computational grid size on the problem simulation with a fully coupled pressure-based algorithm.

Document Type : Research Article

Authors

1 Energy Conversion / Faculty of Mechanical Engineering / Tarbiat Modares University / Tehran / Iran

2 tarbiat modares university

3 tarbia modares university

Abstract

When a shock wave propagates through a flow field with nonlinear thermodynamic properties, different processes occur simultaneously. wave compression, wave refraction, and vortex generation are examples of these processes that cause the waveform and thermodynamic properties of the fluid to change. The interaction of a shock wave with a cylindrical bubble is a simple example of a wave-bubble collision problem in which, the above processes are observed. Due to the high computational cost of density-based algorithms in solving compressible interfacial flows problems such as wave interaction with the two-phase flow, using a fully coupled pressure-based algorithm is a good solution that will solve the problem with proper accuracy while reducing computation time. In this paper, using this algorithm, the interaction of the shock wave with the bubble is investigated; while validating the results, the effect of the computational grid size and the method of discretization of the terms in the governing equations are determined on the results. It was observed that by increasing the number of computational grids according to the first-order upwind method, the simulation results become more accurate, and the numerical diffusion decreases. Also, by changing the discretization method to second-order upwind, the instabilities on the interface of the two phases increase due to spurious fluctuations, and the shape of the interface obtained from the numerical solution moves away from the experimental results.

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