MAC320 CFD 24/25

Suppose you are tracking a fluid particle within a given volume of fluid and that you can compute the total derivative Dp/dt, where p is the density of the fluid, for this fluid particle. In which of the following situations would Dp/dt be equal to zero?

The density of the fluid particle at a fixed location is not changing with time and the velocity of the fluid particle is zero.

Which of the following expressions does NOT mathematically describe a 2D, compressible flow, steady state or transient.

b

What are the variables that will influence shear or normal stresses?

Velocity gradients and viscosity.

Consider the flow between two parallel plates, the top plate moving at velocity Uw and the bottom plate fixed. The plates are located at y=h and y=0, respectively. Which of the following correctly describes the boundary conditions at the walls?

c

Given the wall shear stress Tw, the density p and dynamic viscosity MEW, which of the following is the correct definition for the friction velocity Ur

a

According to the rules for averaging, which of the following will sum up to zero?

The fluctuating component of the flow variable.

Which of the following is NOT an eddy viscosity turbulence model

c

d

d

d

b

c

Discretization of the governing equations results in ___________.

Algebraic equations

d

The order of accuracy m means _____________.

as the grid size is reduced, the approximations converge to the exact solution with an error proportional to m powers of the grid size

d

In sequential methods for solving coupled equations, except the variable for which the equations are solved, the other variables are treated as ___________.

known values

Convergence criterion decides _________.

when to stop the iterations

a

c