Week 1 Assignment 1

Solutions

1. Stream lines can be visualized in an experiment where the flow is unsteady

a) Yes

b) No

c) Yes, provided there is a High-speed camera

d) Can be visualized with a Particle Image Velocimetry (PIV) set-up Ans. (b) No

2. If the flow is incompressible, ______________ of velocity is zero

a) Curl

b) Divergence

c) Gradient

d) Cross product Ans. (b) Divergence

3. Euler equations can be obtained from the Navier-Stokes equation by neglecting _________ term

a) Advection term

b) Diffusion term

c) Pressure term

d) Both a and b Ans. (b) Diffusion term

4. Major difficulty in solving the incompressible Navier-Stokes equation is due to the presence of

___________________

a) Non-linearity

b) Absence of an explicit equation for Pressure

c) Equations are elliptic

d) All of the above Ans. (d) All of the above

5. The Reynolds transport theorem links ________________

a) System approach to CV approach

b) CV approach to system approach

c) Has nothing to do with any of the approaches

d) Both a and b Ans. (a) System approach to CV approach

6. Timelines and Pathlines correspond to ______________ and ______________ formulations

a) Eulerian, Lagrangian

b) Lagrangian, Eulerian

c) None of the above d) Control volume, system Ans. (a) Eulerian, Lagrangian

7. The curves represent which type of fluids?

a) a Dilatant, b Newtonian, c Bingham

b) a Newtonian , b Pseudo-plastic, c Bingham

c) a Bingham, b Dilatant, c Pseudo-plastic

d) None of the above Ans. (c) a Bingham, b Dilatant, c Pseudo-plastic

8. If the flow is irrotational, then _______________

a) b) c) d) Ans. (b)

9. Match the following

a. Dirichlet BC 1.

b. Robin BC 2.

c. Neumann BC 3. d. Cauchy BC 4.

a) a 1, b 2, c 3, d 4

b) a 2, b 3, c 4, d 1

c) a 3, b 2, c -1, d 4

d) a 3, b 4, c 2, d 1 Ans. (c) a 3, b 2, c -1, d 4

10. Match the following,

a. Reynolds number 1. Momentum diffusivity/Thermal diffusivity

b. Nusselt number 2. Inertia force/Gravity force

c. Prandtl number 3. Inertia force/Viscous force

d. Froude number 4. Convective heat transfer/Conductive heat transfer

a) a 1, b 2, c 3, d 4

b) a 2, b 3, c 4, d 1

c) a 3, b 4, c -1, d 2

d) a 3, b 4, c 2, d 1 Ans. (c) a 3, b 4, c -1, d 2

11.

is ____________ in nature

a) Elliptic

b) Parabolic

c) Hyperbolic

d) Mixed Ans. (c) Hyperbolic