Explain hydraulic stress, volume stress and volume strain

Explanation

In above figure, a solid body placed in the fluid under high pressure is compressed uniformly on all sides.
The force applied by the fluid acts in perpendicular direction at each point of the surface and the body is said to be under hydraulic compression. As a result this leads to decrease in its volume without any change of its geometrical shape.The body develops internal restoring forces that are equal and opposite to the forces applied by the fluid.
The internal restoring force per unit area in this case is known as hydraulic stress and its magnitude is equal to the hydraulic pressure (applied force per unit area).
The strain produced by a hydraulic pressure is called volume strain and is defined as the ratio of change in volume `(DeltaV)` to the original volume (V) Volume strain `=(Delta )/(V)`
It has no units or dimensional formula.