Date of Award
School of Engineering
Dr. Wael Mokhtar
Dr. Shirley Fleischmann
Dr. Wendy Reffeor
Most high speed water craft are able to achieve high speeds through the use of a planing hull. Planing hulls use hydrodynamic forces to lift a portion of the vessel out of the water, reducing drag, and allowing for greater speeds. Determining the flow around such vessels is traditionally achieved using a scale model in a tow tank. The purpose of this study was to analyze the performance of a high speed planing hull determine the effects of several geometric features using computational fluid dynamics rather than traditional experimentation. The goal was to determine the best configuration to ensure the lowest resistance on the hull at high speed. This was achieved using STAR CCM+ to solve a three dimensional computational analysis for the multiphase flow and dynamic motion of a planing hull. An initial simulation was created for a 25 ft base hull and validated using experimental data from a towing tank. After developing an accurate simulation for a single hull, the hull geometry was modified to test for the effects of the keel line geometry, deadrise angle, and spray rail location.
A full factorial DOE analysis was performed to examine the effects of the tested geometric features and the interactions between them. The results from this analysis showed that the tested features had a significant effect on the performance of the hull. Increasing the deadrise angle resulted in a decrease in sinkage, an increase in trim angle, and an increase in the total drag on the hull. Raising the keel line height caused a decrease in trim angle and sinkage, while increasing the total drag. These two terms had a significant interaction. As one increased, the relative effect of changing the other also increased for total drag. The final geometric feature tested was the spray rails. Adding spray rails to the bottom of the hull significantly increased the sinkage. Moving the location of the spray rails away from the center of the hull increased the total drag. This showed that the total drag could be significantly reduced by altering these geometric features of the hull.
Crosby, Mowgli J., "A CFD Study on the Performance of High Speed Planing Hulls" (2019). Masters Theses. 966.