Explain hydraulic stress,volume stress and volume strain.

(N/A) When a solid body is placed in a fluid under high pressure,it is compressed uniformly on all sides.
The force applied by the fluid acts in a perpendicular direction at each point of the surface,and the body is said to be under hydraulic compression. As a result,this leads to a decrease in its volume without any change in 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 (or volume stress),and its magnitude is equal to the hydraulic pressure (applied force per unit area).
The strain produced by hydraulic pressure is called volume strain and is defined as the ratio of the change in volume $(\Delta V)$ to the original volume $(V)$.
$\text{Volume strain} = \frac{\Delta V}{V}$
It has no units or dimensional formula.