there are different methods to reduce drag in high speed hulls. one of these methods is a change in the shape of the body by adding longitudinal side tunnels. in this paper it has been attempted to determine the influence of the tunnel height on hydrodynamic characteristics of the hull to achieving an optimum shape for the tunnel. to achieve this purpose, numerical simulation of the problem has...

This article describes a 3D CFD (computational fluid dynamics) simulation implementation of the stepped planning hull in calm water. The turbulent free surface flow around the stepped planing hull is computed with a RANSE method, using the solver ANSYS-CFX. The turbulence model used is standard k–ε. In order to simulate the disturbed free surface, VOF model is implemented. The CFD model has bee...

The wake waves generated by the steady movement of a planing hull are analyzed means towing tank tests. Two sets waves, including divergent and transverse identified then analyzed. wave period is seen to decrease increase in speed vessel. These damp temporally. mechanisms that lead damping were found depend on orbital Reynolds number semi-planing regime, though in-planing regime function boat. ...

By the current paper, lift force that is an important characteristic of a planing hull is calculated. To accomplish this task, Morabito’s mathematical model that has been previously derived for prediction of total pressure distribution on planing hulls is utilized. These equations are not restricted to any specific mean wetted length and can be used for planing hulls with large value of mean we...

In recent years, high-speed vessels such as passenger ships, fishing boats, and pleasure have been operated in various applications. Japan, the method of towing test, characteristics hydrodynamic forces acting on hull, kinetic during running waves studied many occasions particularly for planing semi-planing vessels. However, foreign countries, rectangular-shaped that a large flap at fore part E...

In this paper, the minimization problem of total resistance a planing hull is studied for wide range Froude numbers. The Savitsky method utilized to calculate optimum aspect ratios and dynamic trim angles hull. First, ratios, angles, resistances are calculated with method. Then, minimum drag forces computed each vessel speed by changing systematically. required moments find tab angles. entire c...

One of the most efficient methods of reducing drag on planing craft is the use of transverse step on the bottom of a hull. Applying steps on the hull reduces the contact area with water and as a result, it reduces drag of the craft. Planing craft are able to have one or two transverse steps. In this paper, numerical hydrodynamic performance of the stepped planing craft and its step height effec...

When the planing hull is sailing at high speed, proportion of air resistance to total increases significantly. Therefore, by studying aerodynamic characteristics shape, we can analyze influence shape on performance hull, and find a method reduce resistance. The research took trimaran as object, completed wind tunnel test, established numerical simulation solving RANS equation combining k-ε turb...