An improved Quiet Direct Simulation method for Eulerian fluids using a second-order scheme

  • Authors:

  • M. R. Smith;H. M. Cave;J. -S. Wu;M. C. Jermy;Y. -S. Chen

  • Affiliations:

  • National Center for High Performance Computing, National Applied Research Laboratories, No. 7 R&D Rd. VI, Hsinchu Science Park, Hsinchu, Taiwan and Department of Mechanical Engineering, National C ...;Department of Mechanical Engineering, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 30050, Taiwan and Department of Mechanical Engineering, University of Canterbury, Private Bag 4800 ...;Department of Mechanical Engineering, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 30050, Taiwan;Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand;National Space Organization, National Applied Research Laboratories, 8F, 9 Zhan-Ye 1st Road, Hsinchu Science Park, Hsinchu, Taiwan

  • Venue:
  • Journal of Computational Physics
  • Year:
  • 2009

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Abstract

In this paper, a second-order scheme for the Quiet Direct Simulation (QDS) of Eulerian fluids is proposed. The QDS method replaces the random sampling method used in Direct Simulation Monte Carlo (DSMC) methods with a technique whereby particles are moved, have their properties distributed onto a mesh, are destroyed and then are recreated deterministically from the properties stored on the mesh using Gauss-Hermite quadrature weights and abscissas. Particles are permitted to move in physically realistic directions so flux exchange is not limited to cells sharing an adjacent interface as in conventional, direction decoupled finite volume solvers. In this paper the method is extended by calculating the fluxes of mass, momentum and energy between cells assuming a linear variation of density, temperature and velocity in each cell and using these fluxes to update the mass, velocity and internal energy carried by each particle. This Euler solver has several advantages including large dynamic range, no statistical scatter in the results, true direction fluxes to all nearby neighbors and is computationally inexpensive. The second-order method is found to reduce the numerical diffusion of QDS as demonstrated in several verification studies. These include unsteady shock tube flow, a two-dimensional blast wave and of the development of Mach 3 flow over a forward facing step in a wind tunnel, which are compared with previous results from the literature wherever is possible. Finally the implementation of QUIETWAVE, a rapid method of simulating blast events in urban environments, is introduced and the results of a test case are presented.