二次元非対称急拡大流路内流れの数値的研究 : はく離渦の検討

抄録

This work is part of a continuing research program aimed at clarification and control of the flow structure in an asymmetric expansion channel with local changed channel geometry. Laminar separated flow in two-dimensional symmetric and asymmetric sudden-expansion channels has been investigated numerically. The results of calculation are consistent with flow visualization results. For the asymmetric expansion channel, backward-facing steps of both the upper and lower walls in the channel were placed a distance L_P a part in the streamwise direction. A Navier-Stokes equation was solved by the finite difference method using a pseudo-unsteady technique. The calculations were performed for the cases of eight different distances L_P and of eight different channel expansion ratios a for the range of Reynolds numbers Re≤1600. In this report, the degrees of similarity of separated vortexes and the relation between the flow pattern and the dynamical behavior were examined from the viewpoint of engineering applications.