Learning Forum

[Amirr]

Hello everyone I am using VOF model in Ansys FLUENT and going to calculate the droplet speed in every time step and monitor that.
I wrote this expression but it doesn't get a reasonable result, I wonder if somebody helps me about that
Average(IF(Volumefraction(phase='droplet')>0.99, Position.x, 0 [m]), ['fluid'], Weight='Mass')
Thank you in advance.

[Amine Ben Hadj Ali]

Your expression does not mass-weighed-average the speed but rather the position.

[Amirr]

thank you so much. so what is the correct version?
yes, here first I just want to know the x-location of droplet
then using the below one I am going to find the droplet velocity
Average(IF(Volumefraction(phase='droplet')>0.99, velocity.x, 0 [m]), ['fluid'], Weight='Mass')
but they are not worked

[Amine Ben Hadj Ali]

Use report definition directly without any expressions.
Your formula looks okay so I cannot judge your results. What do you want to do?

[Amirr]

I need the droplet phase speed, location (x, y, separately), how can I get that and monitor them as the simulation runs?

[Amine Ben Hadj Ali]

Create report definitions then allow for writing them into file. You can moreover monitor them during the run.

[smukhopadhyay]

I would like to obtain the droplet velocity and move the mesh with average droplet velocity. Can this be done with expresssion or we need to write an udf?