Volumetric geometry for DSMC and the Voldipar code

•A geometry modeling method from computer graphics is applied to DSMC.•This method is relatively unused in CFD, although suggested peripherally.•Canonical rarefied problems are solved that assess this method.•Faster computations and good scaling makes the method attractive for high-res DSMC.

A quantized, volume-based approach to representing geometry in direct simulation Monte Carlo (DSMC) simulations is presented, and its implementation in a reference code is assessed. Volumetric or discrete/rasterized geometry is shown to be an acceptable way to perform, and possibly accelerate, the particle movement step of the DSMC algorithm. Canonical flow problems are solved that demonstrate the effectiveness of this method. These simulations capture expected results to within a few percent of results obtained from established codes in two-dimensions, and to within engineering tolerances for three-dimensions. The excellent scaling behavior of this approach may allow for high-resolution simulations in significantly less time than more classical geometry representations in DSMC for a given cell gridding method.