CLAWPACK Sample Code

1d Shallow water equations with dam-break initial data.

Set up to solve the same problem as suggested in the tutorial, but using the full nonlinear shallow water equations. Note that the left-going wave is a rarefaction wave but the linearized equations around depth h0 = 10 gives a reasonable approximation to this.

In this example solid wall boundary conditions are applied so that the waves reflect and further interact at later times. Note the jump in depth when a wave reflects at the boundary.

Note also that the interaction of waves looks nearly linear: the waves seem to pass through one another. This is because the variation in depth is small relative to the total depth. Changing the parameters in setrun.py [.html] so that the jump is larger relative to the background depth would reveal more nonlinear interaction.

Plots of results

Fortran files

Makefile [.html]

Determines which version of fortran files are used when compiling the code with make and specifies where output and plots should be directed. Type "make .help" at the Unix prompt for options.

driver.f [.html]

The driver routine allocates storage and then calls the main Clawpack routine.

setprob.f [.html]

A routine by this name is called by the library routine clawpack/1d/lib/claw1ez.f [.html] and is generally used to set any values needed for the specific problem being solved.

rp1sw.f [.html]

This is the Riemann solver, which takes the $q$ values stored in the arrays ql and qr and returns the waves in the array wave and speeds in the array s that result in solving the Riemann problem at each cell interface, and the fluctuations amdq and apdq. See $CLAW/doc/rp1.html for more information about 1d Riemann solvers.

qinit.f [.html]

This subroutine sets the initial data at time $t=0$.

Python files

setrun.py [.html]

This file contains a function that specifies what run-time parameters will be used.

Some parameters that you might want to modify are described in the documentation .

setplot.py [.html]

This file contains a function that specifies what plots will be done and sets various plotting parameters.

Data files

claw.data [.html]

This file contains a number of parameter values that are used by CLAWPACK. The values in this file are read by the library routine clawpack/1d/lib/claw1ez.f [.html].

setprob.data [.html]

This file may contain various parameters used in setting the initial conditions or otherwise setting up the problem.

Library routines

In addition to the Fortran routines in this library, several library routines from $CLAW/clawpack/1d/lib are used. See the Makefile [.html] to determine which ones are used.