u0 1[m/s] Piston velocity amplitude
a 0.1[m] Piston radius
Rmodel 0.2[m] Domain radius
f0 20000[Hz] Maximum frequency
c0 343[m/s] Speed of sound
lam0 c0/f0 Wavelength at f0
ka0 2*pi*a/lam0 k0*a
R0 ka0*a/2 Rayleigh distance at f0
Rfar 20*Rmodel Far-field evaluation distance
Scale a/lam0 Help variable