Large eddy simulation and a simple wall model for turbulent flow calculation by a particle method


Jun Arai, Department of Systems Innovation, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, Japan.



A turbulent channel flow and the flow around a cubic obstacle are calculated by the moving particle semi-implicit method with the subparticle-scale turbulent model and a wall model, which is based on the zero equation RANS (Reynolds Averaged Navier-Stokes). The wall model is useful in practical problems that often involve high Reynolds numbers and wall turbulence, because it is difficult to keep high resolution in the near-wall region in particle simulation. A turbulent channel flow is calculated by the present method to validate our wall model. The mean velocity distribution agrees with the log-law velocity profile near the wall. Statistical values are also the same order and tendency as experimental results with emulating viscous layer by the wall model. We also investigated the influence of numerical oscillations on turbulence analysis in using the moving particle semi-implicit method. Finally, the turbulent flow around a cubic obstacle is calculated by the present method to demonstrate capability of calculating practical turbulent flows. Three characteristic eddies appear in front of, over, and in the back of the cube both in our calculation and the experimental result that was obtained by Martinuzzi and Tropea. Mean velocity and turbulent intensity profiles are predicted in the same order and have similar tendency as the experimental result. Copyright © 2012 John Wiley & Sons, Ltd.