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Problem with time dependence initial conditions

Posted Mar 21, 2020, 9:16 a.m. EDT Heat Transfer & Phase Change Version 5.5 1 Reply

Pablo Vales Castro
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Hello all,

I am trying to do a very simple model of 2 iron blocks in thermal contact where their initial temperatue value is T=0C and only one side (boundary) of one of the blocks is set to T=100C with the "Temperature node". The rest of the faces are thermally insulated.

I do this study as a time dependent evolution, but one thing I noticed is that at t=0 the temperature profile where the boundary is set to 100C is NOT sharp, but has a finite penetration inside the block.

Do you know what might be the problem?

Thank you!

1 Reply Last Post Mar 21, 2020, 3:24 p.m. EDT
Edgar J. Kaiser Certified Consultant
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Posted: 4 years ago Mar 21, 2020, 3:24 p.m. EDT

Pablo,

this lies in the nature of the FE method. What you see is a result of discretization, i.e. the model quantities are interpolated within the mesh resolution according to the discretization you choose. Additionally those quantities get interpreted by the post processing with possibly some smoothing. A sharp transition would result in infinite gradients. You can make the transition steeper by choosing a finer mesh and higher order discretization.

Cheers Edgar

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Pablo, this lies in the nature of the FE method. What you see is a result of discretization, i.e. the model quantities are interpolated within the mesh resolution according to the discretization you choose. Additionally those quantities get interpreted by the post processing with possibly some smoothing. A sharp transition would result in infinite gradients. You can make the transition steeper by choosing a finer mesh and higher order discretization. Cheers Edgar

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