Modeling Boundary Layer Separation Over Bio-Inspired Organized Surface Roughness Elements

Passive flow control techniques are utilized to mitigate turbulence generation, drag, and boundary layer separation. Utilization of organized surface roughness elements as passive flow control methods allows for the manipulation of boundary layer development to reduce drag without needing to put energy into the system while in use. The current study utilizes hydrodynamically smooth bio-inspired surfaces modeled after shark skin (dermal denticles) to delay the boundary layer separation. Simulations were performed using a multi-physics modeling software (COMSOL) to explore various streamwise and spanwise riblet spacing to observe how various packing densities influenced the boundary layer separation point and near-wall Reynolds stresses. By normalizing the lengths and spacings relative to the radius of the structure, a relationship was derived between the spacings and lengths of structures and the boundary layer detachment, as well as the structure spacing's influence on boundary layer development.