A fluid between two very long parallel plates is heated in a way that its viscosity decreases linearly from 0.90 PM at the lower plate to 0.50 PM at the upper plate. The spacing between the two plates is 0.4 mm. The upper plate moves steadily at a velocity of 10 m/s, in a direction parallel to both plates. The pressure is constant everywhere, the fluid is Newtonian, and assumed incompressible. Neglect gravitational effects. (a) Obtain the fluid velocity u as a function of y , u ( y ), where y is the vertical axis perpendicular to the plates. Plot the velocity profile across the gap between the plates. (b) Calculate the value of the shear stress. Show the direction of the shear stress on the moving plate and on the top surface of the fluid element adjacent to the moving plate.
A fluid between two very long parallel plates is heated in a way that its viscosity decreases linearly from 0.90 PM at the lower plate to 0.50 PM at the upper plate. The spacing between the two plates is 0.4 mm. The upper plate moves steadily at a velocity of 10 m/s, in a direction parallel to both plates. The pressure is constant everywhere, the fluid is Newtonian, and assumed incompressible. Neglect gravitational effects. (a) Obtain the fluid velocity u as a function of y , u ( y ), where y is the vertical axis perpendicular to the plates. Plot the velocity profile across the gap between the plates. (b) Calculate the value of the shear stress. Show the direction of the shear stress on the moving plate and on the top surface of the fluid element adjacent to the moving plate.
Solution Summary: The author explains the fluid velocity as a function of y, the viscosity of the upper and lower plates, and the distance between them.
A fluid between two very long parallel plates is heated in a way that its viscosity decreases linearly from 0.90 PM at the lower plate to 0.50 PM at the upper plate. The spacing between the two plates is 0.4 mm. The upper plate moves steadily at a velocity of 10 m/s, in a direction parallel to both plates. The pressure is constant everywhere, the fluid is Newtonian, and assumed incompressible. Neglect gravitational effects. (a) Obtain the fluid velocity u as a function of y, u(y), where y is the vertical axis perpendicular to the plates. Plot the velocity profile across the gap between the plates. (b) Calculate the value of the shear stress. Show the direction of the shear stress on the moving plate and on the top surface of the fluid element adjacent to the moving plate.
Given answers to be: i) 14.65 kN; 6.16 kN; 8.46 kN ii) 8.63 kN; 9.88 kN iii) Bearing 6315 for B1 & B2, or Bearing 6215 for B1
(b)
A steel 'hot rolled structural hollow section' column of length 5.75 m, has
the cross-section shown in Figure Q.5(b) and supports a load of 750 kN.
During service, it is subjected to axial compression loading where one end
of the column is effectively restrained in position and direction (fixed) and
the other is effectively held in position but not in direction (pinned).
i)
Given that the steel has a design strength of 275 MN/m², determine
the load factor for the structural member based upon the BS5950
design approach using Datasheet Q.5(b).
[11]
ii)
Determine the axial load that can be supported by the column
using the Rankine-Gordon formula, given that the yield strength of
the material is 280 MN/m² and the constant *a* is 1/30000.
[6]
300
600
2-300 mm
wide x 5 mm
thick plates.
Figure Q.5(b)
L=5.75m
Pinned
Fixed
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