loads calculation for heat equation

Numerical methods and mathematical models of Elmer
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mulvrova
Posts: 63
Joined: 04 Sep 2009, 10:48

loads calculation for heat equation

Post by mulvrova »

Hello,

I tried to run one of the example cases when calculation loads is used /elmerhome/trunk/fem/tests/heateq_bdf2/. However, temp loads are zero everywhere (check the data.ep file). Do you have any idea why is so?

i use
ELMER SOLVER (v 5.5.0) STARTED AT: 2009/10/26 17:09:22
MAIN:
MAIN: ==========================================
MAIN: E L M E R S O L V E R S T A R T I N G
MAIN: Library version: 5.5.0 (Rev: 4165)
MAIN: ==========================================

results:
Variables in columns of matrix: scalars.result
1: int mean: temp
2: boundary sum: temp loads over bc 1
3: diffusive flux: temp over bc 1
4: boundary sum: loads over bc 1
bash-3.2$ cat scalars.result
3.581161796737E-002 0.000000000000E+000 3.596208250520E+000 8.000000000000E+000
5.338643389410E-002 0.000000000000E+000 1.710885492921E+000 8.000000000000E+000
6.708582357301E-002 0.000000000000E+000 8.325911592627E-001 8.000000000000E+000
7.834255793469E-002 0.000000000000E+000 3.259606889643E-001 8.000000000000E+000
8.795982828213E-002 0.000000000000E+000 -3.791959826471E-002 8.000000000000E+000
1.039189688880E-001 0.000000000000E+000 -5.933520236763E-001 8.000000000000E+000
1.165440976310E-001 0.000000000000E+000 -1.001502856126E+000 8.000000000000E+000
1.266241754267E-001 0.000000000000E+000 -1.312566769601E+000 8.000000000000E+000

regards, Martina.
raback
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Re: loads calculation for heat equation

Post by raback »

The load computation was 1st introduced in the heat equation and the 'Calculate Loads' flag seemed not to be sufficient. Additionally a 'Save Bulk System' flag needed to be true. I just committed a revision 4260. Thanx for reporting.

-Peter
drewcameron
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Re: loads calculation for heat equation

Post by drewcameron »

Hi,

To calculate loads for a heat equation, you first need to determine the heat sources and sinks in the system. These can include things like internal heat generation, heat transfer through boundaries, and any external heat sources.

Once you have determined the heat sources and sinks, you can use numerical methods such as the finite element method or finite difference method to solve the heat equation and calculate the temperature distribution within the system.

To calculate the loads, you can then integrate the heat flux over the boundaries of the system. The heat flux is the rate at which heat energy is transferred across a surface, and can be calculated using the temperature gradient and thermal conductivity at each point on the surface.

By integrating the heat flux over the boundaries, you can determine the total heat transfer in and out of the system, which represents the loads on the system. These loads can then be used to design or optimize the system for the desired performance.

IF you need any help for heat load calculation. I suggest you to visit eds.tech. I will be beneficial

Thanx
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