## Fluids

Topics relate to Fluent, CFX, Turbogrid and more

#### Parametric study for transient case. Is this possible?

• Fika Moktar
Subscriber

I have watched tutorial on parametric study but they are mostly for steady state cases. I want to do parametric study on a transient case by varying its inlet velocity and studying the outlet volume fraction. Is this a possible task or will it be too computational expensive? Is this better to be done manually, case by case? FYI, i am running a 10s simulation (1000 time step with 0.01 time step size)

• Rob
Ansys Employee

Which value would you be studying? Ie if the volume fraction is a function of flow and time how would you compare the output? Manually comparing the curves may be a safer option: make sure you save the monitor data during the run!

• Fika Moktar
Subscriber

im varying the inlet velocity to study the effect of volume fraction across the tube after 10s (ie the dispersion of the particles). If i were to do it manually, can u lead me how can i combine the results in our graph? im plotting volume fraction vs time for different value of inlet velocity.

• Rob
Ansys Employee

If you write the monitor data to file as opposed to just plotting it the output is columnated text which can be read into Excel (other spreadsheets exist) as space delimited text.

• Fika Moktar
Subscriber

Thanks Rob. Since we are at this topic, may I get your help and expertise, to let me know whether reporting data in concentration  (g/L) is possible for Multiphase flow -Eulerian model cases. So far, I am just getting the volume fraction reported out. Is there a cheat sheet or formula code that we can use in the expression since i struggle to write/convert them into suitable representative formula. Appreciate your help.

• Rob
Ansys Employee

You've got volume fraction, and you know the material density. If the latter is fixed it's easier. You also know the cell volume. I may use a Custom Field Function as opposed to an Expression, but the latter is the (newer) better way of working.

• Fika Moktar
Subscriber

will that be written as  ' catalystvolumefraction*catalystdensity*cellvolume' ? or do i need to add any reduction operation such as MassAve, VolumeAve etc?

• Rob
Ansys Employee

That should get you the mass in the cell, and then do the same for the other phase.