Experimental investigation on planing force characteristics of supercavitating vehicles during tail-slap process

The tail-slap of supercavitating vehicles (SVs) has a significant impact on their underwater dynamic behavior and structural safety. In this study, a prescribed-motion water-tunnel experiment is developed to achieve controlled measurement of the dynamic planing force acting on the cylindrical afterbody of an SV oscillating in the gravitational plane. By combining synchronized force measurement with image-based planing-area extraction, the present work quantitatively establishes the relationship between planing area and planing force, and examines the effects of angular velocity ω, Froude number (Fr), and their coupling on tail-slap hydrodynamics. The results show that the planing force is approximately linearly correlated with the planing area within the present experimental range. Increasing Fr reduces both the planing area and the planing force, whereas the direction of ω affects the hydrodynamic response and the critical swing angle θ_c. The influence of ω becomes more pronounced at low Fr. Among the theoretical models examined, the Hassan model provides more accurate predictions of the planing force and performs better under low-Fr and low-ω conditions. These results provide experimental evidence for understanding tail-slap hydrodynamics and support the configuration design and dynamic control of SVs.