Hi Bryce,
I have also encountered this issue when setting up convection and radiation
boundary conditions for a one-dimensional heat transfer analysis. I have
written the following function to extrapolate the temperature at the face, feel
free to use it if it saves you time.
def get_surface_value(T, element_size):
'''
Linear extrapolation of the surface temperature.
Parameters
----------
T An array containing temperature values at the grid
centroids.
element_size The width of each element
Returns
-------
T_surface The temperature at the edge of the first grid element
(surface).
'''
slope = (T[0]-T[1])/element_size
T_surface = T[0] + slope*element_size/2. # centroid-face distance = dx/2
return T_surface.value
Kind regards,
Conor
Conor Fleming
Graduate Mechanical Engineer, Tunnel Ventilation, Fire & Life Safety
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From: [email protected] [mailto:[email protected]] On Behalf Of Daniel
Wheeler
Sent: 18 November 2014 21:30
To: Multiple recipients of list
Subject: Re: Incorrect Face Value for Neumann Boundaries
On Tue, Nov 18, 2014 at 2:32 PM, L.Bryce Whitson Jr.
<[email protected]<mailto:[email protected]>> wrote:
What would be the ill effects of putting a hook in the code that would make the
boundary values correct? It would be a simple extrapolation using half the cell
width and the gradient in the cell.
I don't think it would be a huge issue to make it work correctly. Just a case
of carving out some time to do it. Feel free to submit an issue outlining your
use case, see https://github.com/usnistgov/fipy/issues.
--
Daniel Wheeler
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