Influence on Drag Reduction Characteristics of Jet Hole Shape on Bionic Shark Gill Surface

According to the problem of bionic shark gill jet fluid was able to reduce fluid friction on jet surface, bionic jet surface models were built, which each has different jet hole shape, such as rectangle, arrow-shaped, broken line and other shapes. Models were numerically simulated by using the turbulence model of SST k-ω. The results show that: jet hole of broken line shape has the best drag reduction effect when the flow length and span length of jet hole is constant, and the maximal efficiency of drag reduction is 8.40%. When jet fluid is injected into the transverse mainstream field through jet hole, the jet flow field structure of boundary layer near the jet surface is changed, and countercurrent area is formed on the front stream surface and the back surface of jet hole, which results in reducing the wall shear stress.