Session: 08-04-02 CFD Development II

Submission Number: 157840

Hydrodynamic Characteristics of NACA0012 Hydrofoil with Modified Leading-Edge
Designs under Undulatory Motion 

Undulatory autonomous underwater vehicles (AUVs) are widely recognized for their energy-efficient propulsion, making them ideal for tasks requiring prolonged operation at a constant velocity in steady-state swimming in the marine environment. Despite extensive research on higher thrust generation at inertial regimes, the dynamics of steady swimming, particularly in the viscous-to-transitional flow regimes, remain underexplored. A parametric analysis is conducted over a range of non-dimensional undulation wavelengths (λ* = 0.5 to 0.8) across Strouhal numbers (St =0.1 to 1.0) at two Reynolds numbers encompassing viscous and transitional regime (Re = 100 and 1000) to evaluate the wake characteristics during the drag to thrust transitions and propulsive performance at steady state undulation. Furthermore, a modified foil is designed based on existing undulatory robots, and a two-dimensional numerical comparative analysis is performed against a standard hydrofoil to understand the effects of shape on hydrodynamic characteristics. The increase in St increases the forward force, thereby generating thrust. The wake patterns reveals the reversal of Bénard–von Kármán vortex street during the transition of drag to thrust. The modified profile demonstrates comparable performance to the standard foil, ensuring its effectiveness in alternative design configurations. The outcome of this analysis provides insights into the design concept for the development of advanced undulatory AUVs.

Presenting Author: Narendran Kumar Indian Institute of Technology Madras

Presenting Author Biography: Dr. K. Narendran is a faculty in Department of Ocean Engineering, IIT Madras. His core expertise lies in the field of offshore technology, fluid & wave structure interaction and marine renewable energy systems. He has more than 20 publications in peer-reviewed journals and conferences.