UNSTEADY THREE-DIMENSIONAL NUMERICAL STUDY OF LAMINAR FLOW IN SUDDEN EXPANSION CHANNEL (EFFECT OF ASPECT RATIO)

Three-Dimensional, Unsteady Laminar Flow through Sudden Expansion Channel has been studied numerically. Used rectangular and symmetric sudden expansions (ER=H/h) with different aspect ratio (AR=Wch/h). CFD software ANSYS FLUENT 15.0 was developed to solve the Naviar-Stokes equation by used the finite volume method to transfer these equations from differential form to algebraic form which can be solved by SIMPLE algorithm procedure. The results obtained were represented on graphs and discussed the suitable parameters like: pressure drop, velocity recirculation region and skin fraction coefficient. From the results founded the time steady state increase with the increasing of the aspect ratio and this effects become more clearly at the high of Reynolds numbers and the aspect ratio, so founded high effect of the time on the hydrodynamic parameters, behavior of the flow, recirculation region and the velocity profile, and this effect was clearly at high of Reynolds numbers. Also observed the increasing both the Reynolds numbers and aspect ratio leaded to increase the recirculation zone and streamwise velocity, the pressure drop increase with Reynolds number increase but reduce with increasing the aspect ratio, the results of the numerical study were compared with the other research and obtained acceptable convergence