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Grzegorz
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How to apply external heat flux to a surface with specified "emissivity" boundary conditions in MATLAB R2018 PDE Toolbox?

Asked by Grzegorz
on 14 Feb 2019
Latest activity Edited by Grzegorz
on 18 Feb 2019
I am modelling thermal behaviour of lunar surface, thus it is necessary to specify both heat flux from incident solar radiation and thermal radiation of the lunar surface.
Unfortunately, one of these is ignored, when declared as follows:
thermalBC(thermalmodelT,'Edge',2,'HeatFlux',@SolRad_hf);
thermalmodelT.StefanBoltzmannConstant = 5.670373E-8;
thermalBC(thermalmodelT,'edge',2,'Emissivity',0.98,'AmbientTemperature',3);

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2 Answers

Answer by Ravi Kumar on 14 Feb 2019
Edited by Ravi Kumar on 14 Feb 2019
 Accepted Answer

You can specify all heat fluxes on that BC with a single function call, like:
thermalBC(thermalmodelT,'Edge',2,'HeatFlux',@SolRad_hf,'Emissivity',0.98,'AmbientTemperature',3);
Regards,
Ravi

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Answer by Grzegorz
on 18 Feb 2019
Edited by Grzegorz
on 18 Feb 2019

Thank you Ravi, indeed it works!
There is however another problem: my ~4k nodes model with heatflux and emissivity BCs applied separately require computation time 5,2 seconds and 30 seconds respectively. When these BCs are applied together, the simulation takes about 1040 seconds.
Attempts to compute 20k nodes model results in "out of memory" after about 40 minutes of running. Is the situation normal?
I work on Intel Core i7 and 8GB RAM.

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