Question

define density newton law of viscosity compressibility surface tension pressure in fluid mechanics

Answer 1

Density :- it is define as the ratio of mass of fluid to its volume. It is also know as mass density. It is generally denoted by rho

$rho = \frac{mass \: of \: fluid}{volume \: of \: fluid}$

For standard fluid (liquid) it is 1g/cm³

Or 1000kg/m³

(standard fluid i.e. Water)


Newton law of viscosity :- it States that the shear stress on the fluid element layer is directly proportional to the rate of shear strain.

For removal of proportion we use a constant i.e. Viscosity constant.

$shear \: stress = u \frac{du}{dy}$

There u= viscosity constant


Compressibility :- it is reciprocal of bulk Modulus of elasticity.

Let K= Modulus of elasticity

We know
$k = \frac{compressive \: stress}{volumetric \: strain}$
So compressibility =1/k


Surface tension :- it is define as the tensile force acting on the surface of a liquid in contact with a gas or on the surface between two immiscible liquids such that the contact surface behaves be like membrance under tension.


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