Learning Forum

[gao.1571]

I am testing a welding case with the single reference frame approach. 

The tutorial says a transient problem becomes a steady state problem with the moving reference frame. This is like the welding case where the temperature field reaches a steady state when you travel with the heat source. In welding, the steady temperature field has a ellipse shape because of the welding speed, e.g., 

 

In my model, the cell zone uses frame motion - single reference frame with X velocity v = 0.1 m/s, top surface has a heat source q = f(x,y) and all the surfaces are stationary. Besides, only the energy equation is activated. 

 

The temperature field i get is a circle. It seems like the moving reference frame doesn't work. 

 

Appreciate any help. 

[Prashanth]

Hello,

You mentioned you are using a spatial energy source. Source gets applied over a collection of cells. I believe those cells happen to be within the single zone you that have and moves along.

[gao.1571]

Yes. My heat soure (surface flux) is applied to the top wall with origin being x = 30mm, y = 0 and heat source radius = 3 mm. I want the moving reference frame is attached to the heat source.  

Does my case fit the single reference frame approach? 

[Prashanth]

I don't think SRF approach can be used. Unless you want to turn it into a transient Fluent problem and implement solidification/melting models, transient thermal in mechanical can be used instead.

[gao.1571]

So can you give a reason why it does not work? It does not violate the principle of SRF.