Hi group, I'm been running a 1-D Fokker-Plank advection-diffusion equation under Neumann boundary conditions with a Gaussian distribution as the initial condition:
D = 10.0 > pos = FaceVariable(mesh=mesh, value=mesh.getFaceCenters(), rank=1) > c = 5. eq = TransientTerm() == DiffusionTerm(coeff = D) + > convection(coeff=(c*np.tanh(40*pos))) However, though the initial distribution integrates to 1 over the finite domain, the area under the curve gradually decays as the function converges on the origin (see attachment). This can be witnessed from the numerical outputs starting at step 413 printed on the terminal. *The integration function used is numpy.trapz.* Given the enclosure by the zero-flux boundaries, I can't fathom how this can happen, whether it's a resolvable issues or is conservation not guaranteed under certain conditions. Thank you so much for looking this over. Cheers, Yun -- Graduate Group of Ecology Doctoral Candidate Department of Environmental Science and Policy Center for Population Biology University of California, Davis
s-cd1dx.py
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