Dear Daniel,
thanks for reply
> 1.I have a dependent variable phi(x,y,t). Is it possible to solve the below
> type of equation for this variable:
>
> TransientTerm == DiffusionTerm_x + ConvectionTerm_x + DiffusionTerm_y +
> ConvectionTerm_y,
Use "DiffusionTerm( [ (a, 0), (0, b) ] )" and "ConvectionTerm((c,
d))". There is FAQ in the manual that addresses this.
Sorry, it's not very clear to me. So, the diffusion term turns to be
DiffusionTerm([[[D, 0], [0, 0]]]) OR DiffusionTerm([[D,0]]) if i want d/dx D
d/dx phi in 2D mesh
and convection term
<Some>ConvectionTerm([[U,0],[0,0]]) OR <Some>ConvectionTerm([U,0]) if i want
d/dx U phi in 2D mesh?
> 4.Is it possible to supply the "Terms"(i.e. Diffusion) with exterior
> coefficients so that nabla operator was not applied to them?
Yes. Just do "cellVar * DiffusionTerm(coeff)". cellVar must be a
cellVar. Generally, you can reformulate equations so that everything
is inside the derivatives and this is often preferable. I tried:
dr=0.01
mesh = Grid1D(dx = dr, nx = nsteps)
r = mesh.getCellCenters()
phi = CellVariable(mesh=mesh, name = "none1", value=1.0)
xi = CellVariable(mesh=mesh, name = "none2", value=r)
...
convTerm = PowerLawConvectionTerm(coeff = convCoeff)
diffTerm = xi * DiffusionTerm(coeff = diffCoeff)
And it seems it doesn't work. The output writes:
..
File
"/usr/local/Python26/lib/python2.6/site-packages/fipy/variables/variable.py",
line 936, in <lambda>
return self._BinaryOperatorVariable(lambda a,b: a*b, other)
TypeError: unsupported operand type(s) for *: 'float' and 'instance'
Do you have any ideas why?
