Experimental and Numerical Analyses of the Hydrodynamics of a Shallowly Submerged Underwater Vehicle

Designing an underwater craft that operates near the free surface involves addressing unique challenges resulting from the hydrodynamic interaction of the body and the air–water interface. This study investigates the hydrodynamics of a semisubmersible naval vehicle at shallowly submerged conditions using both experimental and numerical methods. Experiments were conducted at Ata Nutku Ship Model Testing Laboratory using a 1/10 scale model to measure drag forces across various speeds and submergence depths. Computational fluid dynamics simulations were performed to analyze the effects of submergence depth and Froude number on hydrodynamic parameters, including drag, lift, and trim moment, while also evaluating free surface interactions. Numerical results were validated against experimental data with detailed uncertainty analyses, confirming their reliability. The findings illustrate the significant impact of submergence depth and speed on hydrodynamic forces, wave fields, and pressure distributions, offering valuable insights for optimizing the design and performance of shallowly submerged underwater vehicles.