Computational Fluid Dynamics Mock Test 7

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Question 1 of 10

1. The realizable k-ε model falls into which of these categories?

Non-linear two-equation turbulence models

Non-linear three-equation turbulence models

Linear two-equation turbulence models

Question 1 of 10

Question 2 of 10

2. The RNG k-ε model makes assumptions for ___________

small-scale turbulence

kinematic eddy viscosity

dynamic eddy viscosity

large-scale turbulence

Question 2 of 10

Question 3 of 10

3. The relationship between the turbulence intensity T_i and the turbulence kinetic energy k is given by ___________

k=\(\frac{1}{2T_i}(\vec{v}.\vec{v})\)

k=\(\frac{1}{2}T_i^2(\vec{v}.\vec{v})\)

k=\(\frac{1}{2}T_i(\vec{v}.\vec{v})\)

Question 3 of 10

Question 4 of 10

4. The RNG k-ε model comes under which of these types of the turbulence models?

Algebraic model

Second-order closure models

Two-equation model

One-equation model

Question 4 of 10

Question 5 of 10

5. If k is the turbulent kinetic energy, what is the relationship between the turbulence frequency (ω) and dissipation rate of the turbulent kinetic energy (ε)?

ω=ε²/k

ω=ε/k

ω=k²/ε

ω=k/ε

Question 5 of 10

Question 6 of 10

6. When is the LES filter commutative?

When the filter function is uniform

When the filter function is unity

When the filter function is isotropic

When the filter function is quadratic

Question 6 of 10

Question 7 of 10

7. The Spalart-Allmaras model is best suited for ___________

turbulent boundary layers with slight pressure gradients

turbulent mixing layers

turbulent boundary layers with adverse pressure gradients

turbulent jet flows

Question 7 of 10

Question 8 of 10

8. Expand the Reynolds stress term \(-\rho \overline{u_{i}^{'} u_{j}^{'}}\) for the Spalart-Allmaras model.

\(-\rho \overline{u_{i}^{'} u_{j}^{'}} = \rho \overline{v} f_{v1} (\frac{\partial U_i}{\partial x_j}+\frac{\partial U_j}{\partial x_i})\)

\(-\rho \overline{u_{i}^{'} u_{j}^{'}} = \rho \overline{v} f_{v1} (\frac{\partial U_i}{\partial x_i}+\frac{\partial U_j}{\partial x_j})\)

\(-\rho \overline{u_{i}^{'} u_{j}^{'}} = 2\rho \overline{v} f_{v1} (\frac{\partial U_i}{\partial x_j}+\frac{\partial U_j}{\partial x_i}) \)

\(-\rho \overline{u_{i}^{'} u_{j}^{'}} = 2\rho \overline{v} f_{v1} (\frac{\partial U_i}{\partial x_i}+\frac{\partial U_j}{\partial x_j})\)

Question 8 of 10

Question 9 of 10

9. ____________ and _____________ are used in the k-ε model in addition to k and ε to formulate the transport equations.

Rate of deformation and kinetic energy

Internal thermal energy and kinetic energy

Rate of deformation and turbulent stresses

Internal thermal energy and turbulent stresses

Question 9 of 10

Question 10 of 10

10. The first wall damping function in the Spalart-Allmaras model is a function of ___________

the product of the kinematic eddy viscosity parameter and the kinematic eddy viscosity

the ratio of the dynamic eddy viscosity parameter and the dynamic eddy viscosity

the ratio of the kinematic eddy viscosity parameter and the kinematic eddy viscosity

the product of the dynamic eddy viscosity parameter and the dynamic eddy viscosity

Question 10 of 10