Themes > Science > Physics > Mechanics > Fluid Mechanics > Fluid and their Properties > Fluid Properties Examples

1. Explain why the viscosity of a liquid decreases while that of a gas increases with a temperature rise.
The following is a table of measurement for a fluid at constant temperature.
Determine the dynamic viscosity of the fluid.
[4.98 N/m2]
 du/dy (rad s-1) 0 0.2 0.4 0.6 0.8 t (N m-2) 0 0.01 1.9 3.1 4

2. The density of an oil is 850 kg/m3. Find its relative density and Kinematic viscosity if the dynamic viscosity is 5 x 10-3 kg/ms.
[0.85, 1.47 x10-6 m2/s]
3. The velocity distribution of a viscous liquid (dynamic viscosity m = 0.9 Ns/m2) flowing over a fixed plate is given by u = 0.68y - y2 (u is velocity in m/s and y is the distance from the plate in m).
What are the shear stresses at the plate surface and at y=0.34m?
[0.612 N/m2, 0]
4. 5.6m3 of oil weighs 46 800 N. Find its mass density, r, and relative density, g.
[852 kg/m3, 0.852]
5. From table of fluid properties the viscosity of water is given as 0.01008 poises.
What is this value in Ns/m2 and Pa s units?
[0.001008 Ns/m2]
6. In a fluid the velocity measured at a distance of 75mm from the boundary is 1.125m/s. The fluid has absolute viscosity 0.048 Pa s and relative density 0.913. What is the velocity gradient and shear stress at the boundary assuming a linear velocity distribution.
[15 s-1, 0.720 Pa]

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