ランダムフーリエモード法と急激変形理論の複合モデルによる鈍頭物体周りの流れの数値シミュレーション（第1報，複合モデルおよび円柱周りの乱流解析へのモデルの適用）

摘要

A new simulation method to predict turbulence quantities around a bluff body has been developed using a combined model of rnthe random Fourier modes and rapid distortion theory (RDT). In the proposed method, both large- and small-scale turbulent rnmotions are simulated using the random Fourier modes varying in space and time, and the change of vorticity field around the rnbody is modeled by the RDT. The novel advantage of the present method is as follows: 1. we can simulate a rnhigh-Reynolds-number turbulent flow around a bluff body, 2. we can obtain a time dependent fluctuating velocity field at rnarbitrary points around a body, 3. low computational cost compared with DNS and LES. The method is applied to turbulent flow rnaround a cylinder and the results are compared with the previous measurement. The computational results are in agreements rnwith the previous measurements in the front region of the cylinder. It is concluded that the present method is useful to rnsimulate the turbulence fields where the effects of distortion of eddies and blocking by the wall are dominant.%物体周りの流れを明らかにし，その予測を行うことrnは，自動車や船舶，航空機周りの流れの予測や制御のrn問題等と関連して工学設計上非常に重要である．また，rn学術的にも，物体干渉による乱流中の渦構造の変化とrnいう興味深い問題の解明にもつながる．