Research on bioinspired groove design for low-frequency flow noise suppression in towed cable

This study addresses the critical challenge of low-frequency flow noise in turbulent boundary layers (TBL) during the towed cable operations. Inspired by the biomechanical principles of sharkskin structures, we propose bioinspired microgrooved surface design for low-frequency flow noise suppression. By integrating the Stress-Blended Eddy Simulation method with the Ffowcs Williams–Hawkings acoustic analogy theory, a coupled fluid–acoustic numerical model was developed to analyze spectral discrepancies. The hybrid model's accuracy was validated through successive grid refinement iterations, and the spectral characteristic error of numerical prediction was reduced. Four bioinspired groove configurations (rectangular, trapezoidal, triangular, and sinusoidal) were systematically investigated using high-fidelity numerical simulations. The results reveal that the grooves effectively disrupt large-scale vortex coherence, achieving a reduction in wall pressure fluctuation intensity. The rectangular groove exhibited optimal performance at 14 knots, reducing sound pressure levels within the towed cable by 11.92% and 14.5% at 100 and 700 Hz, respectively. Near-field noise attenuation rates reached 21.21% and 20.5% at the corresponding frequencies. Notably, flow noise reduction efficacy was strongly correlated with towing velocity, with microvortex energy dissipation mechanisms becoming dominant in high-speed regimes (>8 knots).