Question

What is shear stress proportional to when applied to a fluid? Write the expression for shear stress.

Answer 1

is Shear stress to proportional when applied What to a Write The expression Stress fluid ? for Shear Solution: is to Shear stress proportional fluid. This velocity gradient (du ) dy to The lace ig applied called When viscosity law Newton's 7 utdu dy u * du y velocity profile at a let us consider Two one and Over The This move a layere distance and ut du & Layers of fluids which of dy. at different velocity say u The viscosity along velocity shear stress acting fluid layers. other now will with gelative between The Causes ď d du 빵 a = u du where ay a = shear stress (w/m?) u = co-efficient of dynamic riscosity (pas) du velocity gradient 왱 page 1

What is Cavitation ? Give an example of when this can occur? The The a The phenomenon of formation of Vapour bubbles 04 a flowing liquid in where region pressure of is called pressure Vapour liquid falls below Cavitation ✓ The in Cavitation Generally Oecurs pumps . pressure works on pumps direction the motor riens The principle of negative impellar in anti clock wise because pressure negative inside pump casing This 억 the that Creates the via foot valre. Sucked water is The at Cross Section water head Outlet Due to varying Increases and run The Centrifugal we close the 16 discharge valve same work 과 as usual perform pump. Impellar and Suck the Water Inside. volieme 7 Water Increases. Inside D is Creates regative pressure out flow pump casing There Since in resistance to The Impellat results It the heat rotation. generation Takes place inside the Impellar The Temperature of water Thes heat Increases casing into steam That Leads to converted finally water get Cavitation page a

hammer provide an Explain water escample in The change pressure as water hammer caused normal below above Or The is defined orapidly pressure by rate of water flow through sudden changes hydrautic to hydro electric power plant The in The in a penstock load On The The "The This water hammer occurs in hydroelectric power plant. whenever The electrical generator drops Suddenly, governor partly closes The Turbine gates. Due to Sudden decrease in rate of water flow to Turbine pressure penstock. pheno action. water hammer effect points penstock between Surge Tank an be Increase in There Will The aresults jen This enomenon hammering The occurs at and The Turbine The in The the erence Laminar flow and dimensional parameter is non The used What is diffen between Turbulent flow What to determine flow Laminar flow here fluid particles in particular direction and parallel to other. in straight are moves line path particles are This each page 3

Turbulent flow path . move in will not pare defined zig zag ion path. Here fluid particle direction. Generally moves They and u 2 is The Tyre 4 5 (ou (Re) In number The forced Convection process determined by help of Re fuL where Reynolds - density lu relocity Le length де dynamic viscosity for flat plate laminar is 5 The flow Then Re <5x10 177 Turbulent 7 is Then The flow 5x105 > Re<10 If 07 pipe for Cylinder is Laminar The Then flow Re < 2000 Turbulent Then the flow Re 2000 77 page 4