Learning Forum

[Celine Lim]

Hello all,

I am currently trying to implement a non-uniform heat flux boundary condition around a cylinder. I have my cylinder split into 4 surface, ie top_left_surface, bottom_left_surface, etc (Figure below) 

For each of the outer tube surface, I am trying to implement a heat flux boundary condition via function expression using a polynomial profile that I curve fitted. The profile is for one quarter of the tube surface is implemented as below: 

Here, I am assuming "0m" when z = 0, y = 23.5m (where radius of the outer surface is 23.5m). Hence, what i am expecting is that at z = 0 and y = 23.5m, the heatflux there should be about 470.1W/m^2. However, the simulation shows otherwise an the heat flux values are far off from what I am expecting.

 

I believe there is something I am not understanding with the cartesian coordinates when I am fitting my heat flux boundary curves, or there is something I am not understanding with implementing a polynomial profile on a curved surface. Any feedback on how I can properly implement this is very much appreciated. 

Thank you,

Celine 

[DrAmine]

You can use that Expression to plot it on the surface right away to verify if it is what you expect before even running.

You z varies over that surface the same with y. If you are doing a fit perhaps number of figures is important. if the have the data in tabaluted form (CSV) and spatial then you can aslo directly read a CSV file to apply it at the boundary.

[Celine Lim]

Dr Amine,

You are right! I actually got the problem figured out, it was due to some mismatch in units. Thank you for taking the time to respond! 

Celine 

[DrAmine]

Welcome!