(584d) Validation of Dynamic Layering in Computational Study of Bristling Shark Denticle

It is well known that shark skin has the amazing ability to provide passive boundary layer control. Small, hinged features called “denticles” automatically lift off the body of the shark with an action called “bristling”. They bristle without control or knowledge of the shark in response to a low-pressure region just outside its body. The bristled denticle blocks backflow and helps to prevent boundary layer separation, which helps the shark maneuver with agility.

This project involves setting up an initial proof-of-concept model with a relatively simple geometry to study the flow around a bristling denticle. To create this model, a 3D moving mesh must be set up that can deform with the motion of the denticle while maintaining the quality of the cells. ANSYS Fluent has several dynamic mesh update methods including remeshing, dynamic layering, and smoothing methods. It is desirable to utilize the dynamic layering tool because of its ability to deal with large boundary displacement while maintaining hexahedral elements. However, more research is required to determine if dynamic layering can provide a robust model in this situation. To test this method, a simple denticle geometry is created and defined to move in a sinusoidal “bristling” motion. Then, the fluid domain is meshed, and dynamic layering is used to update the cells surrounding the moving denticle. These dynamic elements are enclosed within a stationary mesh resulting in several sliding mesh interfaces. To determine the effect of dynamic layering and the sliding mesh interfaces, several tests are conducted to determine how the model behaves with various time steps, momentum spatial discretization schemes, and gradient reconstruction methods.