# What is a free surface moment?

## What is a free surface moment?

A partially-filled tank reduces the hydrostatic stability of the ship by virtue of the shifting of the fluid within the tank. This elevation of the C.G., multiplied by the weight of the ship, is called the free surface moment, or FSM.

## What is free surface effect formula?

This reduction in metacentric height due to free surface effect can be calculated by the following expression: IL = Area moment of the free surface about the tank’s longitudinal centre line. ∇S = Mass displacement of the ship in sea water.

How do you solve free surface effect?

Free Surface Effect can be decreased , to a certain magnitude, by inducing pocketing. Pocketing happens when the surface of the liquid comes in contact with the top or bottom of the tank thereby reducing the breadth of the free surface area.

Why is it important to calculate the free surface effect?

When a tank is partially filled, the liquid’s centre of gravity position will change as the ship is inclined. The free-surface effect can endanger the ship or even lead to a negative metacentric height. Therefore the number of partially filled tanks should be kept to a minimum.

### What is free surface of liquid?

In physics, a free surface is the surface of a fluid that is subject to zero parallel shear stress, such as the interface between two homogeneous fluids. An example two such homogeneous fluids is the liquid water and the air in the Earth’s atmosphere. Unlike liquids, gases cannot form a free surface on their own.

### What is the meaning of free surface?

In physics, a free surface is the surface of a fluid that is subject to zero parallel shear stress, such as the interface between two homogeneous fluids. Unlike liquids, gases cannot form a free surface on their own.

Why is free surface effect important?

What is pocketing in free surface effect?

Free Surface Effect can be reduced, to some extent, by creating pocketing. Pocketing occurs when the surface of the liquid contacts the top or bottom of the tank, reducing the breadth (B) of the free surface area. The Free Surface correction will therefore indicate less overall stability than actually exists.

## What is free surface area?

In physics, a free surface is the surface of a fluid that is subject to zero parallel shear stress, such as the interface between two homogeneous fluids. Its free surface will assume the shape with the least surface area for its volume: a perfect sphere.

What are the factors affecting free surface?

FREE SURFACE EFFECT

• FSE increases with increased length and width of compartment.
• FSE increases when displacement decreases (de-ballasting)
• FSE is independent of the depth of the liquid.

How do you calculate the moment of inertia?

Basically, for any rotating object, the moment of inertia can be calculated by taking the distance of each particle from the axis of rotation ( r in the equation), squaring that value (that’s the r2 term), and multiplying it times the mass of that particle. You do this for all of the particles that make up…

### What is the formula for the moment of inertia?

A hollow cylinder with rotating on an axis that goes through the center of the cylinder, with mass M, internal radius R 1, and external radius R 2, has a moment of inertia determined by the formula: I = (1/2) M ( R 1 2 + R 2 2 )

### What is the unit of moment of inertia?

The unit of moment of inertia is a composite unit of measure. In the International System (SI), m is expressed in kilograms and r in metres, with I (moment of inertia) having the dimension kilogram-metre square. In the U.S. customary system, m is in slugs (1 slug = 32.2 pounds) and r in feet,…

What is the formula for moment of inertia for a circle?

Moment of inertia of a circle or the second-moment area of a circle is usually determined using the following expression; Here, r is the radius and the axis is passing through the centre. This equation is equivalent to I = π D 2 / 64 when we express it taking the diameter (D) of the circle. Sep 5 2019

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