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2-D axisymmetric coefficient form PDE

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Hi,

I want to model the flow around a well in an axisymmetric ground. I selected a 2-D axisymmetric dimension space and I want to solve the groundwater flow equation by using the coefficient form PDE. Is this writen in radial coordinates? I mean the groundwater flow equation in radial coordinates is

K*d2h/dr2 + K/r dh/dr +K d2h/dz2 = 0

where r and z are the coordinates,
h is the pressure head,
d2h/dr2 is the second derivative of h with respect to r
d2h/dz2 is the second derivative of h with respect to z
and K is a constant.

the coefficient form PDE is writen:
grad(-c gradh - ah)+b gradh +ah =f

is this grad with respect to which coordinates? is it cartesian?

thank you.

1 Reply Last Post 22.11.2010, 15:03 GMT-5
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 22.11.2010, 15:03 GMT-5
Hi

normally if you are in 2D axi it a "cylindical grad" development that is active, try it out first on a simple example, always best to check that one understands the notation and the formulas

--
Good luck
Ivar
Hi normally if you are in 2D axi it a "cylindical grad" development that is active, try it out first on a simple example, always best to check that one understands the notation and the formulas -- Good luck Ivar

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