混合時間スケール低レイノルズ数型1方程式乱流モデルによる複雑乱流場解析(流体工学,流体機械)

概要

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To perform massive and unsteady calculations of flow fields, the hybrid RANS/LES method is very useful, in which a RANS is employed near the wall, and an LES is carried out in the region away from the wall. However, to calculate adequately near-wall turbulent motions over complex terrain, a number of grids are needed near the wall. Thus, to reduce the calculation load when predicting real flow fields by computer, solving fewer transport equations is recommended. Therefore, in this study, we construct a low Reynolds-number (LRN) one-equation model for eddy viscosity by introducing a time-scale based on the velocity gradient parameter. This time-scale has proven very effective for predicting local flows over complex terrain. The proposed model is evaluated in complex turbulent flows, such as backward-facing step flow, forward-facing step flow, flow past a two dimensional bock and flow over a curved hill. The predicted results are compared with available experimental data. It is shown that the proposed one equation model reproduces the results generally in good agreement with experimental data.
一般社団法人日本機械学会の論文
2006-07-25