This test case is run with the command
make testThe simulation runs for 500 time steps (
suntans.dat: nsteps = 500) with a time step size of 0.2 s (
suntans.dat: dt = 0.2). For this grid, given that the Voronoi distance for the equilateral triangles with sides of length is m, and the maximum velocity is roughly m s (it actually never exceeds m s), the horizontal Courant number is , and the vertical Courant number is . Because central differencing is employed for advection of momentum (
suntans.dat: nonlinear = 2), the horizontal grid Peclet number must satisfy the one-dimensional stability criterion which requires that . This is an approximation and is not as restrictive as it should be for multidimensional, unstructured-grid problems, but it serves as a good approximation (See Fletcher  for details). For the horizontal stability, then, this requires that m s (
suntans.dat: nuH = 0.025). Likewise, for vertical stability, m s (
suntans.dat: nu = 0.016).
The results can be viewed with the
sunplot gui from the main source directory with
./sunplot --datadir=examples/lockexchange/dataThis will open up a planview of the one-dimensional grid of equilateral triangles, showing that there are 26 (1+
ntout) time steps to plot. To view the profile plot, depress the button with the middle mouse button. The last time step of the velocity vectors along with the salinity field can be viewed with the following buttons:
iskipto 3 to plot every third vector for clarity.