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Depth-dependent temperature as initial values

Posted 13 ott 2022, 14:39 GMT-4 2 Replies

Lujendra Ojha
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Hi, I am pretty new to COMSOL, so this is probably a noob question. But I did scour the internet looking for an answer before posting here.

I am running the 'heat transfer in solid' routine on a simple 2-D geometry. I want the the temperature of the geometry to increase with the Y-axis as my initial value. I have written a simple equation under global definitions to do this.

Let's say the equation called an1 is '20Y', so with every 1 unit of Y, I want the temperature to increase by 20 K. I can plot this under the global definition module and it looks fine.

My question is how do I use this as an initial value. I have defined the Y-extent of my geometry by the parameter 'Tc = 5[m]'. I have 'Temperature' as one of the boundary condition. Under Temperature -> User defined, I have the following equation an1(Tc[m]), but this does not calculate the depth-dependent temperature, but rather imposes a value of 20*5 = 100 K for the entire domain.

Any help is appreciated.

2 Replies Last Post 13 ott 2022, 17:28 GMT-4
Edgar J. Kaiser Certified Consultant
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Posted: 2 years ago 13 ott 2022, 15:57 GMT-4

You must call an1(Y), or something like T0 + an1(Y), if you do not want to start at T = 0 for Y = 0.

Cheers Edgar

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
You must call an1(Y), or something like T0 + an1(Y), if you do not want to start at T = 0 for Y = 0. Cheers Edgar
Jeff Hiller COMSOL Employee

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Posted: 2 years ago 13 ott 2022, 17:28 GMT-4

Hello Lujendra,

One thing that's confusing me in your post is whether you want this termperature distribution to act as a boundary condition or an initial value. If you do want it to be an initial value, then you should not be entering it in a boundary condition - and vice versa. With that said, in a transient problem, you will need to make sure that initial values need to be consistent with boundary conditions.

Jeff

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Jeff Hiller
Hello Lujendra, One thing that's confusing me in your post is whether you want this termperature distribution to act as a boundary condition or an initial value. If you do want it to be an initial value, then you should not be entering it in a boundary condition - and vice versa. With that said, in a transient problem, you will need to make sure that initial values need to be consistent with boundary conditions. Jeff

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