A NUMERICAL STUDY ON THE CONTROL OF THE FLOW IN AN AXISYMMETRIC SUDDEN EXPANSION

A numerical study on the control of the flow and its characteristics in an axisymmetric sudden expansion have been performed considering some stability parameters, including velocity profile modification, wall-shaping, blowing/suction and wall-heating. Due to the fact that numerous cases were tested, the flow was assumed to be two-dimensional, incompressible and laminar in order to use computational time feasibly. The implemented numerical method was validated with the previous experimental and numerical data. Flow characteristics regarding the pitchfork-bifurcation, velocity variations, separation and stain rate relationship, pressure and skin friction coefficients are examined in detail. It was seen that all stability parameters have favourable or adverse effect on the flow asymmetry. The blowing modification has been found to turn the asymmetric flow into symmetric flow provided that adequate blowing mass flow is adopted