The "UNSTEADY_CONVECTION_DIFFUSION_REACTION_1D" script solves the 1D scalar equation of a convection-diffusion-reaction problem with piecewise linear approximation.
For the space discretization the user can choose the standard Galerkin or the Full Upwind approach.
For the time integration the theta-method has been implemented. According to the value of theta these schemes are obtained:
0 -> Forward Euler
1/2 -> Crank-Nicolson
3/4 -> Galerkin
1 -> Backward Euler
The FEM parameters such as the number of finite elements and the number of Gauss integration points can be easily chosen.
The the boundary conditions can be expressed a function of time and a nonlinear source term s(x) can be taken into account.
The functions and the examples are developed according with Chapter 5 "Unsteady convection-diffusion
problems" of the book "Finite Element Methods for flow problems" of Jean Donea and Antonio Huerta.
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