How to specify units of the different physical quantities involved in a simulation?

mesh
1

What is the best way to specify the units of the different physical quantities involved in a simulation in FENICS? starting mesh length units

2

Derive your quantities and take care and be consistent. The physical units from a simulation are your own.

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3

As far as I am concerned there is no way to set the physical quantities of the problem, you should be the one to keep track of the units.
Changing the mesh length can be easily done accessing the coordinates:

mesh = UnitSquareMesh(10,10)
mesh.coordinates()
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4

Thanks for your responses, I am sorry if I am asking something stupid here, but how do I know that if I am modelling heat transfer in a metal bar of 10 units for example, this 10 units correspond to 10 meters or 10 cms. I guess that if I use the MKS system then a unit of temperature correspond to 1 Kelvin and a unit of length to 1 meter? I am wrong in something here?

5

As mentioned by @nate choose what you want but be consistent. You can choose your length units to be cm and temperature in mK but then your thermal conductivity should be expressed accordingly. To avoid any silly mistake, you can stick to MKS system as you mentioned

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6

Hi, I just found an entire book related to this in the following link:

Scaling of Differential Equations

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7

Nice reference. A pity they stuck themselves in python 2. They should update it.