Steady Towing Simulation of Underwater Hairy Fairing Cable System

Hairy fairing cables are used extensively in towed missions because they reduce cable vibration, drag, lift forces, and acoustic noise. On the other hand, accurately estimating the hydrodynamic forces on each cable element of the hairy fairing cables poses a significant challenge in experimentation and computational fluid dynamics (CFD) because of the complex shapes with small hairs. This study examined the depth and tension of the towed cable system based on the proposed mathematical model with a hairy fairing cable. As mentioned in the mathematical model, the hydrodynamic forces of the cable significantly affected the towed cable posture. Therefore, the hydrodynamic forces of the hairy fairing cable were calculated using the CFD method, considering various modeling shapes with a range of inclined angles and Reynolds numbers. The simulation results of the cable depth were compared with sea trial data to validate the accuracy of the proposed approach and hairy shape modeling. This comparative analysis confirmed the reliability of the proposed approach in estimating the posture of the towed cable. In addition, the results also indicate a significant dependence of the hydrodynamic coefficient on the Reynolds number and the inclination angle of the cable element.