URANS studies of hydrodynamic performance and slamming loads on high-speed planing hulls in calm water and waves for deep and shallow conditions

Abstract

URANS capability for hydrodynamic performance and slamming of high speed planing crafts are assessed, using metrics specified for naval applications. Wedge drop validation studies using two different solvers, one single-phase and the other two-phase, shows good agreement with experimental data for time history of pressure gauges. Planing hull validation studies are carried out using the historical benchmark experiments of Fridsma. Simulation conditions include calm water in deep and shallow conditions with fixed and free to sinkage and trim motions, as well as regular and irregular head waves in deep water free to heave and pitch motions. For simulations in calm deep water free to sinkage and trim, grid studies show that refined grid density on the hull, especially over the spray root area, chines, and transom stern are necessary for accurate solutions. Detailed verification and validation studies are carried out with satisfactory results since monotonic convergence and validation are achieved for most of the variables. Additional assessment metrics are studied including wave rise, hull pressure distribution, surface streamlines, existence of porpoising, and main spray trajectory. The results are compared with empirical expressions with reasonably good agreement except for main spray trajectory. Resolving the details of the spray flow is beyond the scope of the current work since finer grid resolution and/or more advanced free surface modeling is required. For simulations in calm deep water with fixed sinkage and trim, the assessment metrics include drag and lift forces, pitch moment, drag-lift ratio, and center of pressure. The results agree well with empirical expressions. For simulations in shallow water, similar studies are carried out and reasonable comparison results are obtained. Seakeeping simulations in regular head waves are carried out and validated with experimental data for response amplitudes and phases, with good agreement. Simulations in irregular head waves are carried out for two different weight configurations and validated against experiments for mean and amplitudes of resistance, heave, pitch, and acceleration. Slamming load analysis is carried out, where both emerging and re-entering slams are detected, although the current experimental data lack slamming pressures for validation. More recent research provides additional studies for calm water motions, slamming pressures, and spray flow trajectory that supports current results.