I am doing some investigations about impulse loadings such as water hammer and slug loads.

CAESAR II provides a specific dynamic technique to solve such problems dynamically based on force spectrum. Theoretically the problem could be solved using time history analysis as well. However, when solving a typical water hammer problem using time history dynamic module the results differ than the results of the water hammer module for the same force-time profile.

Which technique is more accurate and reliable to be used in such impulse loading cases?


Regards,

The "force spectrum" method is an "envelope / statistical" solution. It is the same numeric solution that is used for "response spectrum seismic" evaluations. This method may not be accurate (compared to time history), but it should be conservative.

"Time history" on the other hand is very precise - assuming you know the loading "precisely", and all of your other input data are correct/precise. It is very easy with time history to get the "wrong" answer (because of some uncertainty in the input).