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Development of a Virtual Mesh Refinement Algorithm in a Parallel Unstructured-Grid DSMC Code

C.-C. SU, K.-C. TSENG, J.-S. WU, J.-P. YU, Y.-Y. LIAN

Abstract


In this paper, a virtual mesh refinement (VMR) algorithm for unstructured grids is presented in a parallelized direct simulation Monte Carlo code (PDSC) which features transient adaptive sub-cell (TAS). This algorithm is a virtual mesh refining process, in which the background mesh is refined based on an initial DSMC simulation. The refined cells are designed in a way similar to the structured grid, which makes the particle tracing on them very efficient, unlike on unstructured grids. These refined cells are only used for particle collision and sampling to physically resolve the collision mechanics. Only a refined cell, which includes centroid of the background cell, in a background cell is used for outputing macroscopic data. Two hypersonic flows including a hypersonic cylinder flow and a scramjet flow are simulated. Results show that the simulations using VMR can faithfully reproduce the benchmark case with a much reduced computational time. Corresponding parallel performance of this VMR in PDSC up to 128 processors will be presented in the conference.

Keywords


virtual mesh refinement, parallel direct simulation Monte Carlo, unstructured grid.Text

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