Skip to content
evazlimen edited this page Jul 16, 2024 · 2 revisions

2D Noh Strong Shock

This test highlights the ability of a code to track a high Mach number shock. Parameters from Liska and Wendroff 2003. The test consists of an infinitely strong circular shock radiating from the origin. There is initially a constant density of 1.0 across the grid and a velocity of 1.0 towards the center everywhere. Pressure is set to $10^{-6}$ everywhere. Gamma is set to 1.66666667. This test is performed with the default hydro build (cholla/builds/make.type.hydro) and Van Leer integrator. Full initial conditions can be found in cholla/src/grid/initial_conditions.cppunder Noh_2D().

Parameter file: (modified from cholla/examples/2D/Noh_2D.txt)

Modified to add zl_bcnd=0 and zu_bcnd=0.

#
# Parameter File for the 2D Noh problem described in Liska, 2003.
#

######################################
# number of grid cells in the x dimension
nx=200
# number of grid cells in the y dimension
ny=200
# number of grid cells in the z dimension
nz=1
# output time
tout=2.0
# how often to output
outstep=0.01
# value of gamma
gamma=1.66666667
# name of initial conditions
init=Noh_2D
# domain properties
xmin=0.0
ymin=0.0
zmin=0.0
xlen=1.0
ylen=1.0
zlen=1.0
# type of boundary conditions
xl_bcnd=2
xu_bcnd=4
yl_bcnd=2
yu_bcnd=4
zl_bcnd=0
zu_bcnd=0
custom_bcnd=noh
# path to output directory
outdir=./

Upon completion, you should obtain 201 output files. The initial and final densities and pressures (in code units) are shown below. Examples of how to plot projections and slices can be found in cholla/python_scripts/Projection_Slice_Tutorial.ipynb.
Two 2D histograms side by side, showing density of cells in y direction vs cells in x direction. The leftmost is the initial density plot with a constant density of 1. The rightmost plot is the final density plot at t = 2.0 with a circular region of high density emanating from the origin, peaking around a density of 15. It has a radius of 130 cells. Everywhere else the density is around 4.

Two 2D histograms side by side, showing pressure of cells in y direction vs cells in x direction. The leftmost is the initial pressure plot with a constant pressure of 10^-6. The rightmost plot is the final pressure plot at t = 2.0 with a circular region of high pressure emanating from the origin, peaking around a pressure of 6. It has a radius of 130 cells. Everywhere else the pressure is around 10 ^-6.

We can compare to the Fyris Alpha code:

Clone this wiki locally