Learning Forum

[SaurabhD]

Hi, 

I have created a simulation of a droplet falling on a fiber in Fluent. I want to know the velocity of some specific elements. (Marked with red in the below figure. )

1. Can somebody please guide me on how can I select these points to know there respective x, y, z velocity. 

[Rob]

Which models are you using in Fluent?  You may need to track min/max values of x, y & z on a surface: points in Fluent don't move. 

[SaurabhD]

Hello Sir, 

I am using Multiphase model (VOF).

What do you mean by points in fluent don't move?

Could you please elaborate on any method of calculating the velocities of the specific points. 

I have access to Ansys Learning Hub too so if you have any material in there, even that might help. 

 

[Rob]

If you create a point in Fluent it's fixed at the x, y, z position you defined. If the surface is moving or it's a VOF bubble you may need to track position of the isosurface of volume fraction. 

Read up on monitor points to track the velocity with time, you'll find several examples of these for points/surfaces in the Fluent tutorials. 

[SaurabhD]

Okay, Sir. I'll go through them and post if I come across any difficulty. Thank You!

 

[SaurabhD]

Hello, 

If not using VOF, is there any other way I can get the velocities of the specified points? I need to track the movement of the droplet with time.

Should I use CFX instead of Fluent?

 

[Rob]

What model are you using for the droplet motion?  I think CFX has the same issue, so no benefit using it. 

[SaurabhD]

Okay. 

I had created the droplet using "Region" and specifying a "Spherical" coordinates at the desired location. 

I have also tried drawing sphere on "Space Claim" and during meshing, I defined the sphere as "Fluid". Later, after initialization, I patched the sphere with fluid (Liquid) with VOF = 1. 

 

Can I use Discrete Phase Model to track the fluid particle?

The main motive of the project lies in tracking the motion of certain particles of moving Fluid (Liquid). Could you suggest me any way of doing that? 

[Rob]

Read through VOF, Eulerian and DPM models in the Fluent User's and Theory Guides. This will give you an idea of the model numerics, and limitations. Bearing those in mind, explain exactly what you're trying to figure out.