Simulation and Real (experiment) time

Submitted by NTT1508 on Thu, 12/29/2016 - 13:45

Hi all,

I am confusing about time in CFDEM modelling. For example, I set up the end time in Controldict is 0.2 s. Is this real time ? When comparing with experiment, it does not match. For example the experiment takes much longer time than 0.2 s to get the same condition as generated by simulation. Some published papers report their modelling results with total time 0.02 s for a 0.12x0.06x0.06 m box containing sand; this does not make sense to me at all.

Can some one explain about this ?

Thank you,

Regards,

cgoniva's picture

cgoniva | Fri, 12/30/2016 - 11:35

Hello NTT1580,

from equations point of view the time in the simulation should match the time in the experiment.

Depending on the case this might not be realistic - e.g. onset of a turbulent flow strongly depends on the initial condition, which is in a simulation often "perfect & symmetric" which cannot be the case in an experiment.

Best regards,

Christoph