Target GATE & ESE 2022 (Fluid Mechanics)

 Do you know ?

👉Dynamic viscosity of water is approximately 50 times that of air, but density water is around 850 times more than air so kinematic viscosity of air is more than that of water 

👉 Dynamic viscosity is the property of a fluid in motion.

👉Cavitation occurs when pressure falls below vapour pressure

👉Poise is the unit of dynamic viscosity. (1 poise = 0.1 N-s/m^2 =  Dyne-s/cm^2)

👉Vorticity and stream function parameters exist both in rotational and irrotational flows.

👉Velocity potential function exists only for ideal flow and irrotational flow.

👉Rotation of fluid is always associated with shear stress, because the rotation can be caused only by a torque exerted on the fluid particle and this will be produced by shear force.

👉Flow of blood in veins and arteries occurs as a viscous flow hence laminar.

👉Bernoulli's equation applicable for flow:

            > along a stream line.

            > for steady flow.

           > for incompressible flow.

          > when the effect of viscosity is neglected.

👉Euler's equation is based on momentum conservation, not mass conservation.

👉Couette flow: when one plate is moving and other is at rest

👉 Rouse has developed a criterion for the stability of laminar flow at any point

                              ϰ (chi) = y²ρ (du/dy)/µ