Question

Which of these is a disadvantage of the PISO algorithm?

(a) memory required

(b) small time-steps

(c) computational cost

(d) time required

The question was posed to me in unit test.

Origin of the question is Transient SIMPLE and PISO Algorithms topic in division Transient Flows of Computational Fluid Dynamics

Answer 1

Correct answer is (b) small time-steps

Explanation: The PISO algorithm is advantageous compared to the SIMPLE algorithm that they do not need an iterative process at each time step. But the disadvantage is that they need the time steps to be small enough to produce accurate results.