6

C7122

b) Glycerine flows at a velocity of 5m/s in a 10cm diameter pipe. Dynamic viscosity (6) and density

10

of glycerine is assumed as 1.50Pa.s and 1260kg/m? respectively.
Estimate: 1) The boundary shear stress in the pipe due to the flow.

ii) Head loss in a length of 10m of pipe. iii)
Power developed by the flow in a distance of 10m.

PART 0
Answer any four full questions, each carries 10marks.
Determine the displacement thickness, momentum thickness and energy thickness (10) in

terms of normal boundary layer thickness 6 in respect of the following velocity profile in
⋅ 2 ⋅
the boundary layer on a flat plate = 2 - where ‏لا‎ is theYvelocity at height y above plate
0 5 5

surface and U is the free stream velocity.

Obtain Von — Karman momentum integral equation from conservation principles. (10) 11
a) Derive an expression for i) displacement thickness and ii) momentum thickness. (6) b)
A 2.5m ship model was tested in fresh water ( =1090kg/m?) and measurements (4) indicated
that there was a resistance of 45N when the model was moved at 2m/s. Work out the

velocity of 40m prototype. Also calculate the force required to drive the prototype at this
speed through sea water (=1025kg/m’).

12 a) Define the following: i) boundary layer thickness ii) displacement thickness (4) 111)

momentum thickness and iv) energy thickness.

b) Explain: i)Geometric similarity ii)Kinematic similarity iii) Dynamic similarity. (6) 13 Show
that the power P developed in a water turbine can be expressed as: =

14

37) कु —,( 2 )/-, [ரா] where D and B are diameter and width (10)

of runner, N is the speed in rpm; H is the operating head, ம and ‏م‎ are respectively the
coefficient of dynamic viscosity and mass density of the liquid.

Define the following dimensionless number with their field of application: (10)
i) Froude Number ii) Weber Number iii) Newton number iv) Mach number ****

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