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Laplace equation with Dirichlet boundary conditions in the 2D axisymmetric coordinate system

The aim of this test case is to validate the discretization of the diffusive term of a cell advection/diffusion equation in the 2D axisymmetric coordinate system.

Configurations

Domain is rectangular, its opposite corner coordinates being \((0,0)\) and \((1,1)\).

We solve \(-\Delta T=f\) on the whole domain.

Using cylindrical coordinates, 2D solution of the problem is set to \(\cos(\pi r)\sin(\pi y)\). Right-end-side f is equal to \(2\pi^{2}\cos(\pi r)\sin(\pi y) + \dfrac{\pi}{r}\sin(\pi r)\sin(\pi y)\).

Boundary condition

The symmetry axis is in located on the left at \( r=0.5 \). The global boundary conditions are chosen as follows.

Boundary Condition Value
Top Dirichlet \( T = 0 \)
Bottom Dirichlet \( T = 0 \)
Other Boundaries Neumann \( \partial T = 0 \)
Figure 1: Elevation of the temperature field

Runtime parameters

Energy equation is used:

Comments

Second order spatial convergence is expected.

Results

The grid size starts from 40 in every direction to 640. Second order convergence is observed with \(L_\infty\), \(L_1\) or \(L_2\) norms.

2D results

Mesh Temperature Linf error Order Temperature L1 error Order Temperature L2 error Order
40 8.55732636e-04 n/a 2.69430910e-04 n/a 3.52892413e-04 n/a
80 2.14068698e-04 +1.9991 6.73389943e-05 +2.0004 8.81932983e-05 +2.0005
160 5.35256476e-05 +1.9998 1.68319461e-05 +2.0002 2.20464624e-05 +2.0001
320 1.33819414e-05 +1.9999 4.20792332e-06 +2.0000 5.51149922e-06 +2.0000
640 3.34551808e-06 +2.0000 1.05197011e-06 +2.0000 1.37786755e-06 +2.0000