Pulsation in fluid systems...Is it steady-state or is it transient? Well, it is both. Kind of. Pulsation causes periodic transients that are regular in nature and thus considered steady-state. It can be called "steady-state pulsation".
The problem is not whether pulsation is steady-state or transient. It is whether the frequencies that are excited by the pulsation are at or near the acoustic resonant frequencies of the fluid system. If so, there can be problems. API 674 defines the allowable pulsation limits for positive displacement pumps.
AFT will soon release the new PFA module for AFT Impulse. PFA stands for Pulsation Frequency Analysis. This new module will help engineers predict, understand and avoid resonant frequencies related to the fluid acoustics. It will also help engineers assess whether their system is in compliance with API 674.