The heat accumulation problem of the model

ASPECT
1

Dear professors,

Hello, everyone. My model encountered a very strange problem. As time went by, the heat inside the model seemed to be increasing more and more, and at the same time, I didn’t seem to see any heat dissipation.

As shown in the following video, I drew a white line to represent a temperature of 250k. As time went on, this part began to grow larger and larger.

I’d like to ask where the problem lies in the Settings of my model?

Best wishes,

Lu

man3.prm.txt (3.3 KB)

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041563×856 109 KB

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031559×849 121 KB

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021563×863 121 KB

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2

Hi @ddarkerlu,

Thank you for posting the question to the forum.

A few initial questions and observations:

  1. You are using a constant radiogenic heating model, so that may be contributing to the overall temperature increasing through time through the initial stage of the model. The rate and magnitude of initial temperature increase will depend on a number of factors, including the initial conditions, vigor of convection (determined by various model properties), etc, etc.
  2. Following on the point above, can you make a plot of the average temperature and RMS velocity through time, which should be available in the statistics file? This should give a good indication of whether the system is in terms of reaching steady-state behavior.
  3. After you have the plots from point 2 above, can you compare the patterns with previous similar studies to get a sense for whether anomalous behavior is occurring?

Cheers,

John

4

Dear John,

I’m very sorry for replying to your message so late. I’ve been busy with other things these days. I tried to remove the radioactive heating, but the result seemed to be the opposite of before. Heat is hard to maintain while the cold substances above start to increase.

I’m wondering if other Settings in my model don’t make sense. Do I need to make improvements?

Best wishes,

Lu

5

@ddarkerlu It’s not clear to me that what you observe is wrong. If you don’t have internal heating, but you have cooling through the top boundary, you would expect that the temperature decreases over time. Can you be more specific about what you observe, and why you think that this is wrong?

Best

W.

6

Dear Wolfgang,

Thank you very much for your reply. This is the result of the model after I removed the radioactive heating. I found that the temperature of the upper ice shell part I set is dropping, which limits the heat rise at the bottom. I just think this phenomenon is a bit strange. Is this considered a normal phenomenon in my model Settings?

Best wishes,

Lu

9.2

7

@ddarkerlu You are asking questions about the realism of the model. I don’t know the answer to this question, but it doesn’t not seem “obviously wrong” to me: If you have a low-viscosity top shell, it will in essence lead to a temperature profile that is conductive, rather than convective.

I think you should simplify your model. Start without the low-viscosity shell, convince yourself that the simulation looks reasonable to you, then make things more complex again.

Best

W.

8

Dear Wolfgang,
Thank you very much for your suggestion. I will try it out as you requested.
Best wishes,
Lu