## Matlab Code for 3D Turbulence Simulations

The following .m files implement the simulation described in
our column. You must be running Matlab to use these
files. Choose a grid
size, for example

M=32; N=32; P=32;

Then run the script
initbabc;
This initializes the flow as a superposition of ABC flows
and sets values of other parameters: the time step deltat
for forward integration, the viscosity nu, and the body force
per unit mass g. Other initialization may be added here.
This script calls the function
makek.m.
To integrate forward, invoke rk4;. This
script calls several functions, written as .m files,
nonlinear.m,
fft3.m,
iff3.m.
The flow appears to be turbulent after a transient period
estimated at t=15. The script rk4 can be interrupted with
CTRL-C and restarted where it left off.