GlaDS - how to modify geothermal heat flux?

Extension of Elmer in computational glaciology
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awhite
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GlaDS - how to modify geothermal heat flux?

Post by awhite » 30 May 2019, 03:26

Hi,

I'm setting up a GlaDS model and am trying to see conditions necessary to get channelization under my glacier.
e.g. how strong high geothermal heat flux would needs to be.

How do I adjust geothermal heat flux in GlaDS? Or alternatively the m_b water input term from Equation 12 in Gagliardini '18

From [ELMERICE]/Tests/GlaDS/ i can see the input:

Code: Select all

$Source = 0.0                 ! all input in moulins
I have no moulins, and dont want to add them if possible.

Thanks very much,

Arran

gagliar
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Re: GlaDS - how to modify geothermal heat flux?

Post by gagliar » 03 Jun 2019, 09:58

Dear Arran,

GlaDS doesn't see the geothermal heat flux, but only melt, trough the source term: Hydraulic Potential Volume Source. If you want to include melt from geothermal heat flux (and basal friction and internal deformation) you will have to compute the temperature field and evaluate how much water is produced at the base of the glacier.

Hope it helps,
Regards,
Olivier

awhite
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Re: GlaDS - how to modify geothermal heat flux?

Post by awhite » 04 Jun 2019, 05:18

Dear Olivier,

Thanks for your reply,

What does 'Hydraulic Potential Volume Source' correspond to in your '18 paper with Werder?

Is it m_b (equation 12) from the paper?

Thanks very much,

arran

gagliar
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Re: GlaDS - how to modify geothermal heat flux?

Post by gagliar » 04 Jun 2019, 20:28

Yes, this is m_b from Eq. (12). So in fact, contrary to what I was saying in my previous post, m_b can be directly evaluated as a function of the geothermal heat flux and the frictional heating.

awhite
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Re: GlaDS - how to modify geothermal heat flux?

Post by awhite » 19 Jun 2019, 02:34

Okay great, thanks for that.
On [ELMERICE]/Tests/GlaDS/shmip_B5.sif it says that this source is 'moulin input' - which needs updating.

I am also trying to run a drainage model with a poroelastic sheet where sheet thickness is directly related to effective pressure, h = h(N) --- no opening or closing terms and no dependence on basal velocity.
e.g. equation 5b in hewitt '13 https://doi.org/10.1016/j.epsl.2013.04.022

Is this possible with Elmer/GlaDs?
Id just need to switch off the cavity solver and calculate h_cav as a function of N.

Cheers
arran

gagliar
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Re: GlaDS - how to modify geothermal heat flux?

Post by gagliar » 19 Jun 2019, 09:09

It is not possible to switch off the cavity (just the channels). I guess you will not be able to do what you want directly with the GlaDS solver but you will have to write your own solver with the appropriate h=h(N) function implemented.
Regards,
Olivier

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