Investigation of stepped planning hull hydrodynamics using computational fluid dynamics and response surface method

The use of step at the bottom of the hull is one of the effective factors in reducing the resistance and increasing the stability of the Planning hull. The presence of step at the bottom of this type of hulls creates a separation in the flow, which reduces the wet surface on the hull, thus reducing the drag on the body, as well as reducing the dynamic trim. In this study, a design space was created by making changes to the three input parameters. Input parameters include the linear speed of the hull, the distance from the step from the transom and the change in the step height across the hull. The present study was carried out using the Computational Fluid Dynamics (CFD) coupled with Response Surface Method (RSM). The Computational Fluid Dynamics simulation was done by StarCCM+ software. The design of experiments and the Box–Behnken design method were used to select samples and the Kriging model for the Response Surface Method was used. Genetic Algorithm and screening method were also used to find optimal points. Output parameters include Drag and Lift force on the hull, the total hull trim. The results of the sensitivity analysis on the input parameters show that the hulling speed is the most influential parameter on the value of the output parameter.