sandbox/Antoonvh/lamb_centered.c
A test for the centered Navier-Stokes solver
We advect an initial Lamb-Chaplygin vortex dipole, subject to a viscous force.
The result may be compared against he one obtained with tme mac.h
solver.
#include "grid/multigrid.h"
#include "navier-stokes/centered.h"
#define RAD (sqrt(sq(x) + sq(y)))
#define ST (x/RAD)
const face vector nu[] = {0.01, 0.01};
int main() {
mu = nu;
L0 = 20;
X0 = Y0 = -L0/2.;
N = 256;
run();
}
event init (t = 0) {
double k = 3.83170597;
scalar psi[];
foreach()
psi[] = ((RAD > 1)*((1/RAD))*ST +
(RAD < 1)*((-2*j1(k*RAD)*ST/(k*j0(k))) + (RAD*ST)));
boundary({psi});
foreach() {
u.x[] = -(psi[0, 1] - psi[0, -1])/(2*Delta);
u.y[] = (psi[1] - psi[-1])/(2*Delta);
}
}
event movie (t += 0.1; t < 10){
scalar omega[];
vorticity (u, omega);
output_ppm (omega, file = "movie.mp4", n = 400);
}