Question

Which of these following is used to match the outlet and inlet flow velocities?

(a) uN,j = uN-1,j×\(\frac{M_{in}}{M_{out}}\)

(b) uN-1,j = uN,j×\(\frac{M_{in}}{M_{out}}\)

(c) uN-1,j = uN,j×\(\frac{M_{out}}{M_{in}}\)

(d) uN,j = uN-1,j×\(\frac{M_{out}}{M_{in}}\)

This question was addressed to me during an interview for a job.

I want to ask this question from Boundary Conditions topic in portion Boundary Conditions of Computational Fluid Dynamics

Answer 1

Right choice is (a) uN,j = uN-1,j×\(\frac{M_{in}}{M_{out}}\)

Explanation: To match the flow velocities, velocity in the node immediate west of the outlet is multiplied by the mass ratio \(\frac{M_{in}}{M_{out}}\). This will help us to maintain continuity.