Time varying convection boundary conditions

[ws18]

Dear FEAP team,

I want to ask another question about defining a convection element with time dependent ambient temperatures. More specifically,

q=h(T-Tambient)

'Tambient' in the equation is not constant but changes with time (attached figure may be clearer). Can FEAP handle this type of modeling? Would you please advice me how to realize the simulation if modification or programming is needed? 

Thank you for your attention. 

[FEAP_Admin]

Have a look at "6.3 Convection elements" in the user manual and look at the expression for q_n.  You should be able to figure it out from there.  Think about what you can set q_o to, what you can set p(t) to, what you can set T_o to.

[ws18]

Dear administrator,

Thanks for your reply. I checked the manual but still cannot figure out how to define a time dependent T0. The manual does explain how to priscibe proportional flux q0 by defining p(t), but it seems that the proportional loading value p(t) is not related to T0.

In my case, no constant flux is applied (q0=0), I only need to consider q=h(T-T0). And I want T0 to be time dependent. Would you please further explain it? Thank you.

[Prof. R.L. Taylor]

You should study routines like sbodyf.f (in ./elements/solid2d) to see how body forces are made time-dependent.  Then apply to the value of the parameter used to define T_0 in, say, convec2d.f (in ./elements/thermal).  If you study this well you should be able to figure out how solve your problem.

[FEAP_Admin]

@WS18 you need to think to harder.  What would happen if you made T_o = 0 and defined q_o in term of the T_o you are really interested in?

[ws18]

Dear Prof. Taylor and FEAP_Admin,

Good idea. I should be creative and think twice about the idea of @FEAP_Admin at the very beginning. I will check whether this method works later.

Many thanks for the helps you provided.

Wenya