3. Fluid Mechanics

Computational Fluid Dynamics — Quiz

Test your understanding of computational fluid dynamics with 5 practice questions.

Practice Questions

Question 1

An explicit time-marching CFD solver requires the Courant number $C=\frac{u\Delta t}{\Delta x}\le1$ for stability. Given $u=1.5\,\mathrm{m/s}$ and $\Delta x=0.005\,\mathrm{m}$, what is the maximum allowable time step $\Delta t$?

Question 2

During a grid independence study, velocities at a monitoring point are 2.00\,m/s (coarse mesh), 1.95\,m/s (medium mesh), and 1.93\,m/s (fine mesh). If the criterion for mesh-independent results is a change of less than 2\\% between successive meshes, which meshes have achieved grid independence?

Question 3

For an iterative CFD solver, the residual vector at three control volumes is $r=[1\times10^{-4},-2\times10^{-4},2\times10^{-4}]$. What is the L2 norm of the residual vector?

Question 4

Which boundary condition is most appropriate for specifying a fixed static pressure and allowing outflow of velocity in external flow CFD simulations?

Question 5

Which iterative linear solver is best suited for large, sparse, non-symmetric linear systems in CFD due to its ability to handle non-symmetric matrices efficiently?