326 DNSを用いた複合噴流の能動制御(2)(OS3-6 噴流,後流,せん断流の構造・普遍的特性(噴流4),OS3噴流,後流,せん断流の構造・普遍的特性)

抄録

In order to develop a new mixing procedure, we conduct DNS (direct numerical simulation) of a combined jet, in which four jets are placed on one plane and each jet is directed for a impinging point. Three configuration are examined for several inclination angle of jet, in particular in two of three cases, a swirl motion is produced by adjusting the meeting position. From view of coherent structures, it is found that the impingement enhances the occurence of small scale vortices, while that of large-scale structures does not definitely appear. Also to compare the mixing efficiency, a statistical entropy is calculated for all cases. As a result, the swirl motion contributes to the increase of mixing efficiency, however, because of the lack of large-sale structures, the jet expansion of all cases are suppressed.