Learning Forum

[bv169]

Hello,

I am trying to look at acceleration of a specific phase in my model. I used CFD post calculator to find the average velocity in an isovolume of that phase. This worked, but when using these velocity values to calculate acceleration (using different timesteps), the acceleration values are not realistic whatsoever. I am wondering if this calculation in CFD post may be inaccurate, or if there is a better monitor for acceleration of a specific phase within Fluent?

 

Thanks,

Breanna 

[Rob]

I'd do it directly in Fluent. You want to report the flow time, velocity, volume fraction and mass of the phase. The latter two are to confirm you have enough phase mass to have a meaningful result.  You also need to check the flow field: is there something happening to cause a mean value to fluctuate significantly? 

The added bonus of the monitors over using CFD Post is the data is retained every time step so you don't need as many data files. 

[bv169]

Thank you. I was able to add monitors for all of the variables you listed except 'volume fraction'. When adding the expression: Volumefraction(phase='water') it says the expression cannot be single valued. Is there an easier way to add this monitor? Thanks. 

[Rob]

I tend to use the reports so facet max/min/average rather than expressions. 

[bv169]

Perfect, that worked. Thank you!