Explore topic-wise MCQs in Computational Fluid Dynamics.

This section includes 10 Mcqs, each offering curated multiple-choice questions to sharpen your Computational Fluid Dynamics knowledge and support exam preparation. Choose a topic below to get started.

1.

The mixing length for a 2-D turbulent boundary layer depends on ____________

A. the distance from the wall and the boundary layer thickness
B. the distance from the wall and von Karman’s constant and dimensionless distance
C. von Karman’s constant
D. the boundary layer thickness
Answer» C. von Karman’s constant
Discussion
2.

Consider a turbulent flow of viscosity μt, diffusivity Γt and Prandtl/Schmidt number σt. Let Φ be a flow property which can be decomposed into Φ=Φ+Φ’. What is the turbulent scalar flux given by?

A. –ρu’Φ’=Γt\(\frac{\partial\Phi}{\partial x}\)
B. –ρu’Φ’=Γt\(\frac{\partial\Phi}{\partial x}\)
C. –ρu’Φ’=μt\(\frac{\partial\Phi}{\partial x}\)
D. –ρu’Φ’=μt\(\frac{\partial\Phi}{\partial x}\)
Answer» B. –ρu’Φ’=Γt\(\frac{\partial\Phi}{\partial x}\)
Discussion
3.

Mixing length model cannot be used for _____________

A. turbulent jets
B. turbulent mixing layers
C. turbulent wakes
D. turbulent flows with separation
Answer» E.
Discussion
4.

The mixing length model can be used to get the turbulent scalar fluxes also using _____________

A. turbulent Prandtl/Reynolds number
B. turbulent Reynolds/ Schmidt number
C. turbulent Prandtl/Schmidt number
D. turbulent Reynolds/Nusselt number
Answer» D. turbulent Reynolds/Nusselt number
Discussion
5.

What is the mixing length for the outer layer of a 2-D turbulent boundary layer?

A. 0.09 times the boundary layer thickness
B. 0.08 times the boundary layer thickness
C. 0.07 times the boundary layer thickness
D. 0.06 times the boundary layer thickness
Answer» B. 0.08 times the boundary layer thickness
Discussion
6.

For a 2-D flow, what is the mixing length of the mixing layer turbulence model?

A. 0.1 of layer width
B. 0.09 of layer width
C. 0.08 of layer width
D. 0.07 of layer width
Answer» E.
Discussion
7.

The value of mixing length depends on ____________

A. small eddies
B. large eddies
C. turbulence
D. time scales
Answer» D. time scales
Discussion
8.

If νt is the turbulent kinematic viscosity, lm is the mixing length and U is the mean flow velocity in the x-direction, which of these gives the Prandtl mixing length model equation?

A. \(ν_t =l_m^2 \Big|\frac{∂U}{∂x}\Big|\)
B. \(ν_t =l_m^2 \Big|\frac{∂U}{∂y}\Big|\)
C. \(ν_t =l_m \Big|\frac{∂U}{∂y}\Big|\)
D. \(ν_t =l_m^2 \Big|\frac{∂U}{∂x}\Big|\)
Answer» C. \(ν_t =l_m \Big|\frac{∂U}{∂y}\Big|\)
Discussion
9.

The mixing length model links _____________ with _____________

A. length scale with mean flow properties
B. velocity scale with mean flow properties
C. length scale with position coordinates
D. velocity scale with position coordinates
Answer» C. length scale with position coordinates
Discussion
10.

The mixing length model defines the turbulence dynamic viscosity as a function of ____________

A. position
B. mean flow properties
C. fluctuating components
D. velocities
Answer» B. mean flow properties
Discussion