Prediction of High-Speed Planing Hull Resistance and Running Attitude - A Numerical Study Using Computational Fluid Dynamics

Abstract

Accurate predictions of the resistance and running attitude are key steps in the process of hull design and manufacturing. The predictions have traditionally relied on model testing, but this technique is both expensive and time consuming. In this study, the performance of CFD simulations of planing hulls is evaluated using two commercial software: ANSYS FLUENT, developed by ANSYS, Inc., and STAR-CCM+, developed by CD-adapco. This was done by predicting the steady resistance, sinkage and trim angle of one semi-planing and one planing hull in calm, unrestricted water. The Reynolds averaged Navier-Stokes equations with the SST k-! turbulence model was used along with the volume of fluid method to describe the two-phase flow of water and air around the hull. Furthermore, a two degrees of freedom solver was used together with dynamic mesh techniques to describe the fluid-structure interaction. The simulations were performed with both fixed and free sinkage and trim to make careful comparisons of the software and with experimental data. The results from the fixed sinkage and trim simulations of the planing hull in FLUENT and STAR-CCM+ show a good consistency. However, there is a significant difference in the pressure resistance obtained from the two codes that could not be explained. The free sinkage and trim simulations were mainly conducted in STAR-CCM+ due to problems with obtaining a stable solution in FLUENT. Froude numbers between 0.447 and 1.79 were simulated and the results follow the same trends as what is seen in the experimental data. The calculated resistance, sinkage and trim angle show good correspondence to experimental data in the planing region, where the errors of the predicted values are below 10%.