Dear Zhekai,
My October 11th post to this list affects my recommendation to you from October
4th. You'll probably be fine if you aren't running your simulation for long,
but if you are running it for long periods, it will likely become cripplingly
slow. I've implemented the corrected version below for you, which should not
have a memory leak because of the method of updating the boundary condition.
I hope that helps.
Best regards,
- Ian
phi_1_initial, phi_2_initial = 0.0, 0.0
D1, D2 = 1.5, 1.75
dx_1 = [0.03806023, 0.10838638, 0.16221167, 0.19134172, 0.19134172, 0.16221167,
0.10838638, 0.03806023]
dx_2 = [0.03806023, 0.10838638, 0.16221167, 0.19134172, 0.19134172, 0.16221167,
0.10838638, 0.03806023]
mesh_1 = Grid1D(dx=dx_1, Lx=1.0)
mesh_2 = Grid1D(dx=dx_2, Lx=1.0)
phi_1 = CellVariable(mesh_1, value=phi_1_initial)
phi_2 = CellVariable(mesh_2, value=phi_2_initial)
eq_1 = TransientTerm() == ExplicitDiffusionTerm(coeff=D1)
eq_2 = TransientTerm() == ExplicitDiffusionTerm(coeff=D2)
phi_1.faceGrad.constrain(0.5, where=mesh_1.facesLeft)
phi_1.constrain(1.0, where=mesh_1.facesRight)
inlet_BC_value = Variable()
phi_2.faceGrad.constrain(inlet_BC_value, where=mesh_2.facesLeft)
phi_2.faceGrad.constrain(-0.5, where=mesh_2.facesRight)
timeStepDuration = 0.9 * min(dx_1)**2 / (2 * max(D1, D2))
steps = 100
viewer = Viewer(vars=(phi_1, phi_2))
for step in range(steps):
eq_1.solve(var=phi_1, dt = timeStepDuration)
inlet_BC_value_new = phi_1.faceValue[mesh_2.faceCenters == 1.0] #
Acquire the data
inlet_BC_value.setValue(float(inlet_BC_value_new))
# Apply that data on the 2nd mesh
eq_2.solve(var=phi_2, dt = timeStepDuration)
viewer.plot()
From: [email protected] [mailto:[email protected]] On Behalf Of Zhekai
Deng
Sent: 05 October 2016 05:20
To: [email protected]
Subject: Re: how to set up data transfer between two adjacent nonuniform meshs
Hi Ian,
Thank you very much for the example and pointing out the additional reference.
Those are very useful informations. This approach seems intuitive and easy to
incorporate into the code. I will try to incorporate it into my own code.
Thanks again.
Best,
Zhekai
On Tue, Oct 4, 2016 at 5:23 AM, Campbell, Ian
<[email protected]<mailto:[email protected]>> wrote:
Hi Zhekai,
There is.
Try the following, where as you suggest, the interpolated value at the
right-most face of mesh_1 is used. That (outward flowing) flux value is then
copied to the inlet boundary condition (Neumann/flux) for mesh_2. A diffusion
equation with a different coefficient for your solution variable phi is defined
on the 2nd mesh - this should work if you change the equation further. Both
meshes are non-uniform and of unit length.
I don't know from your question what type or magnitude boundary conditions
you're interested in on the other faces, but nonetheless, you can see in the
figures produced from the code below that the outlet flux on the right-most
face of mesh_1 is equal to the inlet flux on the left-most face of mesh_2.
There's likely a cleaner way to do this, by updating the value of the boundary
condition for mesh_2 rather than re-defining it, but this is a start.
An additional reference for you, here is Dr. Guyer's suitably-named Gist:
https://gist.github.com/guyer/bb199559c00f6047d466daa18554d83d
Let us know if that works for you.
Best,
- Ian
phi_1_initial, phi_2_initial = 0.0, 0.0
D1, D2 = 1.5, 1.75
inlet_BC_value_init = 2.0
dx_1 = [0.03806023, 0.10838638, 0.16221167, 0.19134172, 0.19134172, 0.16221167,
0.10838638, 0.03806023]
dx_2 = [0.03806023, 0.10838638, 0.16221167, 0.19134172, 0.19134172, 0.16221167,
0.10838638, 0.03806023]
mesh_1 = Grid1D(dx=dx_1, Lx=1.0)
mesh_2 = Grid1D(dx=dx_2, Lx=1.0)
phi_1 = CellVariable(mesh_1, value=phi_1_initial)
phi_2 = CellVariable(mesh_2, value=phi_2_initial)
eq_1 = TransientTerm() == ExplicitDiffusionTerm(coeff=D1)
eq_2 = TransientTerm() == ExplicitDiffusionTerm(coeff=D2)
# Boundary Conditions
phi_1.faceGrad.constrain(0.5, where=mesh_1.facesLeft)
phi_1.constrain(1.0, where=mesh_1.facesRight)
phi_2.faceGrad.constrain(inlet_BC_value_init, where=mesh_2.facesLeft)
phi_2.faceGrad.constrain(-0.5, where=mesh_2.facesRight)
timeStepDuration = 0.9 * min(dx_1)**2 / (2 * max(D1, D2))
steps = 100
viewer = Viewer(vars=(phi_1, phi_2))
for step in range(steps):
eq_1.solve(var=phi_1, dt = timeStepDuration)
inlet_BC_value = phi_1.faceValue[mesh_2.faceCenters == 1.0] #
Acquire the data
phi_2.faceGrad.constrain(inlet_BC_value, where=mesh_2.facesLeft) # Apply
that data on the 2nd mesh
eq_2.solve(var=phi_2, dt = timeStepDuration)
viewer.plot()
From: [email protected]<mailto:[email protected]>
[mailto:[email protected]<mailto:[email protected]>] On Behalf Of
Zhekai Deng
Sent: 04 October 2016 03:29
To: [email protected]<mailto:[email protected]>
Subject: how to set up data transfer between two adjacent nonuniform meshs
Hello All,
I wonder is there any way to allow the data share on the two nonuniform mesh's
interface ? To explain this, let's say I have two meshes, mesh_1 and mesh_2.
Different equations govern the mesh_1 and mesh_2, and solution variable on both
meshes is phi. I would like the outlet (on the right face) on mesh_1 served as
inlet(on the left face) on mesh_2.
I tired to concatenate two mesh. If they are uniform, this works fine. However,
if two does not share the exact the same face (for example, one is uniform, and
another is nonuniform), there seems to be problem. .
Thus, I wonder is there any way to "interpolate" the phi.facevalue on mesh_1
outlet face, and apply this interpolation value into the inlet of mesh_2?
Best,
Zhekai
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