wssrwsmt said:The viscous hydrodynamic forces will increase with increase of the velocity of ship？ Can the viscous hydrodynamic forces be neglected if the velocity of ship is small ？
Thanks for your answer.SteamKing said:Not entirely.
The resistance of a vessel is composed of two parts: the frictional resistance and the residuary or wave-making resistance.
For vessels whose Froude number is less than 0.1, the residuary resistance can be neglected.
(The Froude number is a non-dimensional quantity relating the length and speed of a vessel, Fn = (V/gL)1/2)
The viscous forces produce the frictional resistance of a hull and are always present as long as the vessel is in motion, although at diminishing magnitude.
Viscous hydrodynamic forces are a type of resistance that a ship experiences as it moves through water. These forces are caused by the friction between the water and the hull of the ship, and they can significantly impact the ship's velocity and overall performance.
Viscous hydrodynamic forces act in the opposite direction of a ship's movement, slowing it down and reducing its velocity. The magnitude of these forces depends on the ship's shape, speed, and the properties of the water it is moving through.
The magnitude of viscous hydrodynamic forces is influenced by several factors, including the ship's size and shape, the speed at which it is moving, the properties of the water such as viscosity and density, and the presence of any external factors such as waves or currents.
Studying the effects of viscous hydrodynamic forces is crucial for ship design as it allows engineers to understand how different hull shapes and designs will perform in water. This analysis helps in optimizing the ship's design for maximum efficiency and minimum resistance, thereby improving its velocity and performance.
Yes, there are several methods that can be used to reduce the impact of viscous hydrodynamic forces on a ship. These include optimizing the ship's hull shape, using specialized coatings to reduce friction, and implementing energy-saving technologies such as air lubrication systems or hull air cavities. Other methods include altering the ship's speed and route to avoid unfavorable water conditions and using technologies such as thrusters or stabilizers to counteract the effects of these forces.