A multivariate investigation of bio-inspired geometries on rocket fins in subsonic and supersonic flow

The aerodynamic efficiency of a rocket is significantly influenced by its fin design. This study explored the use of bio-inspired fin geometries on shark skin riblets and humpback whale tubercles to reduce drag on a model rocket in both subsonic (30 m/s) and supersonic (Mach 1) flow regimes using Computational Fluid Dynamics (CFD). Simulations in ANSYS Fluent were performed for a conventional smooth fin (baseline) and for fins with riblet and tubercle modifications. The bio-inspired designs altered the boundary layer on the fin surfaces, affecting flow separation and pressure distribution. Key results indicated that whale-inspired tubercle fins consistently lowered drag in both speed regimes by up to 11%, by delaying flow separation and reducing pressure drag. Shark skin riblets displayed mixed performance: they increased drag at low speed, due to higher skin friction, but achieved a 6% drag reduction at Mach 1 by mitigating form drag in the wake. These findings demonstrate the potential of nature’s geometries on rocket fins to strategically leverage turbulence for drag reduction.