# Theory-based Quiz

#### Total number of Questions - 45

Times up! Real Viscous Flows

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1 / 45

One of the assumption of the Blasius solution for laminar boundary layers is that:

2 / 45

Which of the following state variables are introduced using the second law of thermodynamics?

3 / 45

In which of the following cases is friction drag dominant?

4 / 45

For an inertially dominant flow, based on Prandtl's boundary layer theory, the effect of the viscosity is ________

5 / 45

Compared to the Blasius solution for a flat plate, the Falkner-Skan solution takes into account:

6 / 45

You were asked to analyze the flow of water (assumed incompressible) through a pipe with constant diameter and were told that the flow is fully-developed. Which of the following mean quantities do you expect to be remain constant along the length of the pipe?

7 / 45

Which of the following is a scope for analyzing external flows?

8 / 45

Which of the following are examples of Internal flows?

9 / 45

Any turbulent flow property can be decomposed into the following two components:

10 / 45

Which of the following cases could be predicted by Reynolds stress models, while eddy viscosity models could fail?

11 / 45

Conduction heat transfer can occur in:

12 / 45

For a laminar flow over a flat plate, the shear stress is dependent on the following factors:

13 / 45

In order to close the RANS equations ______ need to be modeled.

14 / 45

For a flat plate with a sharp leading edge, which of the following is the appropriate range of Reynolds number for the onset of turbulence, where $x$ is the distance from leading edge of the plate.

15 / 45

The minor losses at the entrance of a pipe, especially due to a sharp turn at the corner, are due to: 16 / 45

In internal flows, fully-developed region refers to a region in which _______

17 / 45

Which of the following can be considered as a minor loss in internal viscous flows?

18 / 45

The point of separation of the boundary layer can be reasonably estimated by monitoring the location where ______ becomes approximately zero.

19 / 45

When analyzing an object moving in a stationary reference frame, the no-slip condition on the object surface is defined as:

20 / 45

According to the Stefan-Boltzman law, the relationship between the emissive power ($E_b$) of an ideal blackbody and the absolute surface temperature ($T_s$) is:

21 / 45

For an external flow over a 2D cylinder the flow:

22 / 45

Analytical solutions can be obtained for external flows over:

23 / 45

The viscous losses in a laminar pipe flows do NOT depend on:

24 / 45

What is the thickness of a NACA 0015 airfoil profile, relative to its chord length?

25 / 45

When performing an analysis in the stationary ambient frame of a maneuvering vehicle, the velocity of the solid body ($\vec{V}_{solid}$) is:

26 / 45

When a laminar viscous fluid is flowing over a flat plate, the boundary layer thickness at distance $L$ on the flat plate is $\delta$. If we double the velocity of the fluid, the new boundary layer thickness at the same location of the flat plate, assuming the flow is still laminar, is:

27 / 45

For a round pipe, if the flow is turbulent, the entrance length can be estimated as _____, where $D$ is the diameter of the pipe and $Re$ is the Reynolds number of the flow based on the diameter

28 / 45

A boundary layer is a thin region near the ___________ where __________ effects are important.

29 / 45

For a fluid expanding suddenly into a pipe (as shown in the figure), which of the following statement are true? 30 / 45

In ________, heat is transferred from more energetic to less energetic particles because of molecular interactions.

31 / 45

In the context of laminar-turbulent transition, critical Reynolds number refers to the Reynolds number at which ______

32 / 45

For a straight leveled pipe the head loss is caused by:

33 / 45

For a turbulent flow, which of the following statements are true regarding the small scale eddies?

34 / 45

Heat is always transferred:

35 / 45

The wall shear stress exerted by a flow over any body acts:

36 / 45

According to Kutta-Joukowski theorem, any 2D body in relative motion to the ambient fluid with velocity $V$ has a lift force that is given by

37 / 45

Compressibility is the inverse of

38 / 45

The only mode of heat transfer occuring in vaccuum is:

39 / 45

The energy of the smaller eddies in a turbulent flow is converted into heat because of:

40 / 45

In a CFD simulation of a viscous fluid flow over a 2D symmetric airfoil, the concept of boundary layers is important near the _____________ 41 / 45

Which of the following is an example of a jet?

42 / 45

As a 2D laminar jet spreads, its centerline velocity decays as:

43 / 45

For a flat plate, the flow along the plate is considered entirely laminar if the Reynolds Number based on the length of flat plate:

44 / 45

Which of the following have a direct impact on the laminar-turbulent transition in boundary layer? (Select the three correct answers.)

45 / 45