Calculating Kinematic Viscosityįind the kinematic viscosity of an oil having density of 981 kg/m 3. The fluid viscosity between plates µ = 8.33 x 10 -4 poise 3. Substiututing in the above equation we get Let the fluid viscosity between plates is µ Using the equation we haveĭu = Change of velocity = u-0 = u = 0.60m/s Velocity of upper plate u = 60 cm/s = 0.6 m/sįorce on the upper plate F = 2.0 N/m 2 (This is the value of shear stress i.e., τ ) Determine the fluid viscosity between the plates.ĭistance between plates dy = 0.025mm = 0.025x 10 -3m Problem Statement: A plate, 0.025mm distant from a fixed plate, moves at 60 cm/s and requires a force of 2 N per unit area (2 N/m 2) to maintain this speed. (ii) Shear stress at y = 0.15 m is given by Let us differentiate w.r.t y on both sides, we get du/dy = 2/3 -2y (Take dynamic viscosity of the fluid as 8.63 poises.) Determine the shear stress at y = 0 and y = 0.15m. Problem Statement: The velocity distribution over a plate is given by u = (2/3) y – y 2 in Which u is the velocity in metres per second at a distance of y metre above the plate. Calculating Shear stress of a Viscous Fluid Let us solve some of the example problems to understand how we can use the above-given relations, equations and unit derivations to determine Shear stress in a viscous fluid.
This is all about the Viscosity of Fluid. Proportional to the rate of shear strain (or velocity gradient), is known as an ideal plastic fluid. Ideal Plastic Fluid: A fluid, in which shear stress is more than the yield value and shear stress is.Quicksand, putty Paint, Blood, melted butter. In other words, the viscosity of the fluid increases or decreases when shear is applied. Non-Newtonian Fluid: A real fluid, in which the shear stress is not proportional to the rate of shear strain (or velocity gradient), is known as a Non-Newtonian fluid.Water, air, alcohol, glycerol, and thin motor oil are all examples of Newtonian fluids. Newtonian Fluid: A real fluid, in which the shear stress is direct and proportional to the rate of shear strain (or velocity gradient), is known as a Newtonian fluid.All the fluids, in actual practice, are real fluids. Real Fluid: A fluid, which possesses viscosity, is known as real fluid.Ideal fluid is only an imaginary fluid as all the fluids, which exist, have some viscosity I deal Fluid: A fluid, which is incompressible and is having no viscosity, is known as an ideal fluid.Let us discuss these types of fluids definitions. The fluids may be classified into the following five types : The above equation shows that with the increase in temperature, the viscosity increases. The above equation shows that with the increase in temperature, the viscosity decreases.
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