Brodogradnja · 2023 · 16 citations · 62 references
EngineeringMarine EngineeringMechanical EngineeringComputational Fluid DynamicsFluid DynamicsNaval ArchitectureComputational AerodynamicsFrictional ResistanceHigh-speed Craft DesignHull Form DesignResistance Of High-speed CraftShip Performance PredictionDynamic TrimHigh-speed Craft HydrodynamicsHull ResistancePlaning Hull DesignPlaning Hull ResistancePlaning HullsTotal ResistanceTrim
Stepped planing hulls, including single and double steps, are increasingly used to lower drag by reducing wetted area and improving lift‑to‑drag ratios. This study investigates how varying the positions of the first and second steps on a double‑stepped hull influences total resistance, dynamic trim, and dynamic sinkage using computational fluid dynamics. Using CFD, the authors derived a non‑dimensional equation {(x1−x2)/L + (x1x2)/(LB)} × Fr∇ that links step positions to resistance, trim, and sinkage. Results show that shortening the gap between steps and moving both steps aft reduces total resistance, while shifting the steps forward decreases dynamic trim and sinkage.
Along with developing high-speed craft technology, the planing hull is growing with modifications for better performance. One such technology is stepped hull, both single and double. Planing hull with steps allows the boat to run at a relatively low drag-lift ratio with lower frictional resistance due to reduced wetted area. In this study, the hull was modified with variations in the position of the double steps, which aimed to determine the effect of the first and second step positions on the total resistance, dynamic trim, and dynamic sinkage generated by computational fluid dynamics (CFD). Based on the analysis results, variations in the position of the stepped can change the hull performance. Shortening the distance between the two steps and moving both rearwards toward the transom can lower the total resistance. The dynamic trim and dynamic sinkage decreased as the position of the two steps was shifted further forward. An equation created in a non-dimensional form relates the positions of two steps to the desired results of total resistance, dynamic trim, and dynamic sinkage, namely: {(x1-x2)/L + (x1x2)/(LB)} × Fr∇, where x1 is distance the first step from transom, x2 is the distance of the second step, L is the length of the boat, B is the beam of the boat, and Fr∇ is the volume Froude number.
62
A new k-ϵ eddy viscosity model for high reynolds number turbulent flows
Tsan-Hsing Shih, William W. Liou, Aamir Shabbir et al. · Computers & Fluids · 1995 · 5.9K citations