Numerical Study on Two-Dimensional Symmetric Sudden Expansion Channel Flow : Dynamic Characteristics

The objective of this study is to examine mumerically the relation between the flow structure and the dynamic characteristics for a laminar separated flow through a two-dimensional symmetric sudden-expansion channel of expansion ratio α. A stream function-vorticity formulation was used and solved by the finite difference method using a pseudo-unsteady technique. For the cases of four different expansion ratios α=2, 3, 3.5 and 4, calculations were performed for the range of the Reynolds number 20≤Re≤400. The results showed that the critical Reynolds number ReC (at which the asymmetric flow began) decreased with increasing α. Stream lines, velocity profile, distributions of pressure and pressure gradient were presented and discussed to clarify the relation between flow pattern and pressure gradient.