# Computational Fluid Dynamics Questions and Answers – Incompressible Flows – SIMPLEC Algorithm

This set of Computational Fluid Dynamics Multiple Choice Questions & Answers (MCQs) focuses on “Incompressible Flows – SIMPLEC Algorithm”.

1. 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. 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. 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. 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. 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.
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6. 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. 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. 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. 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. 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

Explanation: As the SIMPLEC algorithm is more converging than the SIMPLE algorithm, the SIMPLEC has more convergence per iteration, less number of iterations and hence less total computational cost than the SIMPLE algorithm. But, the computational cost per iteration is the same for both.

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