2D Dispersive Transport in a Uniform Flow Field (diagonal)
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Introduction
~~~~~~~~~~~~
This test problem is a slight modification of the previous test,
the direction of the velocity field is rotated by :math:`45^\circ` 
counter clockwise with respect to the mesh.


Defining Variables
~~~~~~~~~~~~~~~~~~
The background mesh consists of square cells with size :math:`H=15` m.
It has 83 grid cells in the x-direction and 37 grid cells in the y-direction. 
The mesh is gradually refined toward the source such that the well is
represented by a square cell of :math:`h=0.46875` [m] (:math:`h = H/32`).
The mesh refinement adds 8.4% more cells.

.. figure:: figures/mesh.png 
    :figclass: align-center

    **Computational mesh with 7468 cells.**


Results and Comparison
~~~~~~~~~~~~~~~~~~~~~~
The plume structure is characterized by three line cuts.
The first cut is given by line :math:`y=0` that goes through the well.
The two other cuts are given by lines :math:`x=0` and :math:`x=424`.

.. figure:: figures/plume_centerline.png 
    :figclass: align-center
    :width: 600 px

    **Concentration along plume centerline (y=0) from upgradient to downgradient**

.. include:: table_values_centerline.txt

The analytic data were computed with the AT123DAT software package.
A difference observed near downstream boundary for the Amanzi with the 
first-order transport scheme (Amanzi(1st)).
The second-order transport scheme provides excellent match.

.. figure:: figures/plume_transverse_well.png 
    :figclass: align-center
    :width: 600 px

    **Concentration transverse to the flow field from plume centerline at x=0.**

.. include:: table_values_cross_a.txt

.. figure:: figures/plume_transverse_dnwind.png 
    :figclass: align-center
    :width: 600 px

    **Concentration transverse to the flow field from plume centerline at x=420.**

.. include:: table_values_cross_b.txt



