Exploring the Capabilities of a 3D Printed Flexible Shark Skin Model to Control Flow Separation

Separation causes significant problems for many engineering applications, and the flexible shark scales found on the shortfin mako shark have been shown to passively control both turbulent and laminar flow separation. 3D printed models inspired by mako shark scales that can passively bristle in a flow have been proven successful in reducing flow separation. To better understand the capabilities of a 3D printed shark scale model with passively bristling scales (max angle of 50 degrees), a rotating cylinder inside of a water tunnel was used to induce an adverse pressure gradient and thus a region of separation on a flat plate. The rotating cylinder can affect the magnitude of the adverse pressure gradient and separation by changing rotational speed and distance from the plate. To test the shark scale model’s ability to control flow, cylinder speeds were varied to determine the max adverse pressure gradient at which the flow was controlled by the shark scales. Analysis was performed utilizing particle image velocimetry. The velocity field allowed for analysis of the size and characteristics of the separation bubble by using backflow coefficient, turbulent kinetic energy, vorticity, and normalize Reynolds shear stress.