Important Questions - Unit II: Flow through Pipes and Boundary Layer

 1) Explain the experiment setup to study different types of flow.

2) Derive an expression for drop of pressure for a given length of pipe when fluid is flowing through a pipe

(or)

Derive Hagen - Poiseuille formula.

3) Explain the existence of laminar sub layer in the boundary layer theory. 

4) Derive an expression for head loss for the laminar flow through a pipe line.

5) Derive an expression for average velocity for a flow through pipe. Find the ratio of maximum velocity to average velocity.

6) Derive an expression for co-efficient of friction in viscous flow in terms of Reynolds number.

7) Explain the concept of boundary layer in pipes for both laminar and turbulent flows with neat sketches

8) Derive the expressions for following

(i) Displacement thickness (δ*)

(ii) Momentum thickness (θ)

(iii) Energy thickness (δ **)

9) For a flow of viscous fluid flowing through a circular pipe under laminar flow conditions show that the velocity distribution is a parabola. And also show that the average velocity is half of the maximum velocity.

10) Compare laminar & Turbulent flow.

11) Prove that the variation of velocity is parabolic in the case of laminar flow occurring through a circular pipe.

12) Derive Chezy's formula for loss of head due to friction in pipe.

13) Derive an expression for the power transmission through the pipes. Find also the condition for maximum transmission of power.

14) Derive an expression for Darcy - Weibach equation to determine the head loss due to friction.

15) What do you understand by equivalent sand grain roughness for commercial pipe?

16) Explain the characteristics of laminar and turbulent boundary layers.

17) Show that the energy thickness of boundary layer flow is given by,

18) What do you mean by separation of boundary layer? What is the effect of pressure gradient on boundary layer thickness.

19) Determine the equivalent pipe corresponding to 3 pipes in series with lengths and diameters l1, l2, l3, d1, d2, & d3 respectively.

20) What do you understand by total energy line, hydraulic gradient line, pipes in series, pipes in parallel & equivalent pipe.

21) Explain the different methods of preventing the separation of boundary layer. 

22) With a neat sketch explain the development of boundary layer along a thin flat smooth plate held parallel to a uniform flow and explain the salient features. 

23) Derive the energy equation of compressible fluid flow. What important relations are obtained by apploning the energy equation to the isothermal and adiabatic processes? 

24) If the velocity distribution in a laminar boundary layer over a flat plate is given calculate the value of δ, δ*, θ and the shear stress.