Surface-sampled simulations of turbulent ow at high Reynolds number
A new approach to turbulence simulation,based on a combination of large-eddy simu- lation (LES) for the whole flow and an array of non-space-filling quasi-direct numerical simulations (QDNS),which sample the response of near-wall turbulence to large-scale forcing,is proposed and evaluated.The technique overcomes some of the cost limitations of turbulence simulation,since the main flow is treated with a coarse-grid LES,with the equivalent of wall functions supplied by the near-wall sampled QDNS.Two cases are tested,at friction Reynolds number ReT= 4200 and 20000.The total grid count for the first case is less than half a million and less than two million for the second case,with the calculations only requiring a desktop computer.A good agreement with published DNS is found at ReT = 4200,both in terms of the mean velocity pro- file and the streamwise velocity fluctuation statistics,which correctly show a substantial increase in near-wall turbulence levels due to a modulation of near-wall streaks by large-scale structures.The trend continues at ReT = 20 000,in agreement with experiment,which represents one of the major achievements of the new approach.A number of detailed aspects of the model,including numerical resolution,LES-QDNS coupling strategy and sub-grid model are explored.A low level of grid sensitivity is demonstrated for both the QDNS and LES aspects.Since the method does not assume a law of the wall,it can in principle be applied to flows that are out of equilibrium.
Turbulence simulation channel flow high Reynolds number
Neil. D. Sandham Roderick Johnstone
University of Southampton, Southampton SO171BJ, UK
国际会议
The 8th International Conference of Computational Fluid Dynamics, (ICCFD8)(第八届国际计算流体力学会议)
成都
英文
1-11
2014-07-25（万方平台首次上网日期，不代表论文的发表时间）