MCQOPTIONS
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MCQOPTIONS
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. |
What is the difference between the RANS model and the Reynolds stress model? |
| A. | The RANS model needs 5 extra transport equations |
| B. | The Reynolds stress model needs 5 extra transport equations |
| C. | The RANS model needs 7 extra transport equations |
| D. | The Reynolds stress model needs 7 extra transport equations |
| Answer» E. | |
| 2. |
To close the RANS equations, we need _____________ |
| A. | Incompressible flow model |
| B. | DNS method |
| C. | Turbulence models |
| D. | SGS model |
| Answer» D. SGS model | |
| 3. |
The Reynolds stress term arises in the turbulent equation only when ____________ |
| A. | two quantities are correlated |
| B. | two quantities are uncorrelated |
| C. | the flow is steady |
| D. | the flow is unsteady |
| Answer» B. two quantities are uncorrelated | |
| 4. |
From which of these terms does the turbulent viscosity arise from? |
| A. | \(\frac{\partial(\overline{\rho}\tilde{u})}{\partial t}\) |
| B. | \(-\frac{\partial\tilde{p}}{\partial x} \) |
| C. | \(div(\mu grad\widetilde{(\vec{V})})\) |
| D. | \(\frac{\partial\overline{(\overline{\rho}u{‘}v{‘})}}{\partial y}\) |
| Answer» E. | |
| 5. |
How many additional terms are present in the x-momentum equation Reynolds-Averaged Navier-Stokes equations? |
| A. | No additional terms |
| B. | Six additional terms |
| C. | Three additional terms |
| D. | Two additional terms |
| Answer» D. Two additional terms | |
| 6. |
Reynolds averaging makes the conservation equations ____________ |
| A. | non-conservative |
| B. | non-linear |
| C. | unstable |
| D. | inconsistent |
| Answer» C. unstable | |
| 7. |
Which of these terms arise in the conservation equations when using the RANS model? |
| A. | Reynolds stresses and turbulent scalar flux |
| B. | Cross stresses and turbulent scalar flux |
| C. | Leonard stresses and turbulent scalar flux |
| D. | Leonard stresses and cross stresses |
| Answer» B. Cross stresses and turbulent scalar flux | |
| 8. |
For unsteady turbulent flows, which of these averaging method is used? |
| A. | Time averaging |
| B. | Ensemble averaging |
| C. | Spatial averaging |
| D. | Volume averaging |
| Answer» C. Spatial averaging | |
| 9. |
The averaging interval in RANS equation is based on ____________ |
| A. | the grid size |
| B. | the eddy size |
| C. | the fluctuations |
| D. | the time interval of the problem |
| Answer» D. the time interval of the problem | |
| 10. |
Which of these properties of turbulence is ruled out in Reynolds averaged equations? |
| A. | Fluctuations |
| B. | Turbulence |
| C. | Non-linearity |
| D. | Randomness |
| Answer» B. Turbulence | |