Engineering Questions with Answers - Multiple Choice Questions

# Computational Fluid Dynamics – Incompressible Flows – SIMPLEC Algorithm

1 - Question

What does the ‘C’ in SIMPLEC algorithm?
a) Continuation
b) Converging
c) Corrected
d) Consistent
Explanation: SIMPLEC expands as SIMPLE-Consistent algorithm. It was built by Von Doormal and Raithby in the year 1984. It is advantageous over both the SIMPLE and SIMPLER algorithms.

2 - Question

Which of these equations of the SIMPLE algorithm is manipulated in the SIMPLEC algorithm?
a) Continuity equation
b) Momentum equation
c) Pressure equation
d) Pressure-correction equation
Explanation: The SIMPLEC algorithm uses the same procedure as the SIMPLE algorithm. The major difference is that the momentum equation which is used by the SIMPLE algorithm is changed in the SIMPLEC algorithm.

3 - Question

Which of these is affected by the change in the SIMPLEC algorithm?
a) Velocity correction
b) Pressure equation
c) Pressure-correction equation
d) Velocity-correction equation
Explanation: The momentum equation used by the SIMPLEC algorithm is modified. This modification directly affects the velocity-correction equation. This gives an advantage to the SIMPLEC algorithm.

4 - Question

The SIMPLEC algorithm _________ in the SIMPLE algorithm.
a) omits over-relaxed terms
c) omits less significant terms
d) omits under-relaxed terms
Explanation: The SIMPLEC algorithm omits some less significant terms in the SIMPLE algorithm. So, the velocity correction equations of the SIMPLEC model in all the three directions has fewer terms than the SIMPLE algorithm.

5 - Question

The velocity correction in the SIMPLEC algorithm is __________
a) the weighted average of the neighbouring corrections
b) the weighted average of the current pressure values
c) the weighted average of the older pressure values
d) the weighted average of the older velocity values
Explanation: The SIMPLEC algorithm assumes that the velocity correction at the central node as the weighted average of the corrections at the neighbouring nodes. This changes the momentum and the velocity-correction equations.

6 - Question

Which of these is an advantage of the SIMPLEC algorithm over the SIMPLE algorithm?
a) No over-relaxation
b) No under-relaxation
c) No undershoots
d) No extra terms
Explanation: In the SIMPLE algorithm, the whole momentum equation is used. So, for the correction of pressure and velocity, an under-relaxation factor is used. But, as the SIMPLEC algorithm omits all the insignificant terms in the momentum equation, this under-relaxation becomes unnecessary.

7 - Question

Which of these performance-based advantages does the SIMPLEC algorithm have?
a) More stable
b) Faster convergence
c) Bounded solutions
d) Conservativeness
Explanation: As some of the terms in the momentum equation are omitted in the SIMPLEC algorithm, the velocity correction suits the momentum equations more. Therefore, the rate of convergence increases in this algorithm.

8 - Question

What is the advantage of the SIMPLEC algorithm over the SIMPLER algorithm?
a) No extra equations
b) No extra terms
c) No momentum equation
d) More stable
Explanation: The SIMPLER algorithm has an extra equation when compared to the SIMPLEC and SIMPLE algorithms. But, the SIMPLEC algorithm increases the performance of the SIMPLE algorithm without any extra terms.

9 - Question

Which of these facts about the SIMPLEC algorithm is correct?
a) The discretized pressure-correction equation is difficult to solve than that in the SIMPLE algorithm
b) It does not need a pressure correction equation
c) It is computationally expensive
d) Wrong pressure field will influence the velocity field
Explanation: The effect of the pressure field on the velocity field in the SIMPLEC algorithm is the same as the SIMPLE algorithm. A wrong pressure field will result in a bad velocity field too.

10 - Question

Which of these performance characters of the SIMPLEC algorithm match with the SIMPLE algorithm?
a) Convergence per iteration
b) Number of iterations
c) Cost per iteration
d) Total computational cost