正方形急拡大流路を通過する三次元非定常層流の数値的研究

抄録

Three-dimensional numerical predictions are presented for a laminar flow through a square channel with a sudden expansion of area ratio 4：1 in the range of Reynolds numbers Re = 20 to 1,900, using an Open Source CFD Toolbox (OpenFOAM). In particular, the effect of pressure gradient on the secondary flow, shear layer and the bifurcation of flow structure downstream of the sudden expansion was investigated. The results showed that the secondary flow induced by the pressure gradient existed along the shear layer upstream of the area of the disordered motion, and the secondary flow made the stream-wise vortex in the shear layer. So that, the high value of stream-wise fluctuating velocity also distributed in the shear layer.