単体建物モデルを対象とした乱流モデル，乱流シュミット数の影響の検討: CFDによる建物近傍の汚染質拡散の予測精度に関する研究　その1

摘要

建物近傍での汚染質の拡散性状を正確に予測することは，空調設備の 給排気口の設計等において重要な課題の一つである。建物近傍の汚染質 の拡散現象については，これまでに風洞実験を中心とした研究が数多く 行われており，外気取り入れ口を設計するための経験式等の基 礎資料が得られている。%The prediction accuracy of the flow and dispersion around a cubic building with a flush stack located on the roof were examined using various k-ε models. Numerical results were compared with the wind tunnel data. The standard k-ε model provides inadequate results for concentration field, because the basic flow structure such as the reverse flow on the roof can not be reproduced with this model. However, the revised k-ε models considered provide concentrations in better agreement with the experimental data. It is also confirmed that the prediction accuracy of the velocity field strongly affects that of the concentration field. The general agreement with the experiment in the RNG case was the best among the turbulence models tested. For computations with various turbulent Schmidt numbers, Sc_t, the results using Sc_t = 0.3 gave better agreement with the wind tunnel data than those using Sc_t = 0.7 and 1.0. It was confirmed that the predicted concentrations by all CFD models were less diffusive than those of the experiment and the results were largely dependent on the value of turbulent Schmidt number.