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Non-Stationary Advection-Diffusion simulation

Note: these tutorials have been tested with version 18.10. They will not work with previous versions.

The following tutorial will guide you through all the steps to conduct a 2D Non-Stationary Advection-Diffusion simulation of Fecal Coliforms. Like in the first test case (Tutorial 1), there won’t be partitioning nor renumbering, the problem will run on one processor.

To the commands of H2D2 seen in the previous tutorial, we will be adding the following features:

  1. As this test case is non-stationary, it introduces a notion of time step in the resolution process.
  2. This test case will include post-treatment during the resolution; introducing the notions of:
    • triggers (procedure initiating an action at each specified time step, and therefore setting a new delta T for a given strategy)
    • probes (applied on nodes, it measures or extracts a value at a particular point (node)).
  3. Finally, the post-treatment during resolution for this tutorial will include a reduction operation, in contrast to the first tutorial. More information can be found in the Advanced Chapters section.

The domain being considered for the simulation is a closed basin with a predominant longitudinal dimension and negligible flow velocity. A C0 concentration of dissolved degradable contaminant, in this present case Fecal Coliforms, is imposed in x = 0. Without current, the contaminant is spreading exclusively with molecular diffusion and is degrading at a rate defined by Kd.

A 5-meter long by 1-meter wide domain is being considered. The lateral boundaries are defined by a Neumann boundary condition. The global degradation coefficient influence has been studied on a 200 x 10 mesh with a Crank-Nicholson temporal scheme with a time step ∆t=10s.

Like in the first Tutorial, the input files that will be used in this Tutorial 2 can be found in the Input files section.

Chapitre: tutorial 2 ( 1 / 30 )

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