Experimental Study of the Effect of Pulsatile Flow on Corner Vortices at the Sudden Contraction Before the Inlet of Two Parallel Narrow Rectangular Channels

Abstract Corner vortices can be found in regions where there is considerable flow expansion or contraction. Experimental measurement was used to investigate the changing vortices at the contraction region before a dual parallel channel arrangement. The flow in the loop was pulsatile with a flow period of 5 s, amplitude between 0.2 and 0.4, and flow rate in the range of 0.4 m3/h to 0.9 m3/h. The mean transient flow rate in the loop was within ± 6% of the ideal sinusoidal fluctuation at lower amplitude. The corner vortices were analyzed by their change in size during pulsation and the turbulence structure in the contraction area. The corner vortexes are quasi-symmetrical at the channel corners below the contraction plane. The corner vortices were larger when the flow velocity was off-peak. Regions of slower flow increased during the deceleration half-cycle of the pulsatile flow. The results provide more explanation of flow behavior at channel corners and contraction planes.