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Consider transient convection-diffusion equation defined on the unit square [0,1]x[0,1],
with homogeneous Dirichlet conditions on the whole boundary.
Convection field is a pure rotating one and source term is
where  ,
 and
 .
Figure aside shows this source term at t = 0.
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As in the previous example, solution can be computed using three time integration schemes
(Crank-Nicolson, R22 or R33) and five different spatial discretization formulations
(standard Galerkin, least-squares, SUPG, GLS or SGS).
The proposed problem has been solved for 
using a uniform 40x40 bilinear mesh.
Figures below show solution at t = 5 computed using Crank-Nicolson
method with the standard Galerkin formulation.
Time step has been chosen to have a Courant number 1. Therefore, instabilities are due to
the Galerkin formulation.
Solution is clearly improved if stabilized formulation is used.
Figures below show solution at t = 5 computed using the SUPG formulation.
Similar results are obtained if some other stabilization technique is used.
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