ALE手法を用いた運動する車両周りの非圧縮性LES解析 : 第1報,基本的な流れ場における離散化手法の比較検討(流体工学,流体機械)

元データ 2010-04-25

概要

Our objective is to perform Large Eddy Simulation (LES) of incompressible flows around an automobile with motion using arbitrary Lagrangian-Eulerian (ALE) method without decrease in accuracy. For LES of incompressible flows, the discretization method that conserves not only the mass and momentum but also the kinetic energy is preferable, because such conservation properties enable us to conduct computations without any numerical viscosity. We consider a discretization method as a suitable one to LES using ALE method, which is based on colocated grids, and Crank-Nicolson method is employed for the time advancement. Although it dose not fully conserve the kinetic energy discretely, the error is estimated O (Δt^2), which is expected to be insignificant. On the other hand, we also constructed a fully conservative method of kinetic energy on colocated grids, following the quadratic conservative schemes proposed by Morinishi. Moreover, it is clarified that the conservation properties of the other conventional methods are inferior to the two methods mentioned above. The methods are examined in uniform flow and channel flow calculations with moving and transformed grids. The computational results reveal that both two methods mentioned above give similar results. In addition, the obtained results are better than those with other conventinal methods, where the conservation properties somewhat worsen by using Adams-Bashforth method for the time advancement or using the convection velocity vector that does not fully satisfy the divergence-free condition. The present two methods are expected to make it possible to perform LES using ALE method without any numerical viscosity.

著者

野中 聡 旭川医科大学耳鼻咽喉科・頭頸部外科学講座
佐藤 範和 (株)豊田中央研究所
稲垣 昌英 (株)豊田中央研究所
稲垣 昌英 豊田中研

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