from amuse.lab import *
def hydro_sink_particles(sinks, bodies):
all_lost_particles = Particles()
for s in sinks:
xs,ys,zs=s.x,s.y,s.z
radius_squared = s.radius**2
insink=bodies.select_array(lambda x,y,z: (x-xs)**2+(y-ys)**2+(z-zs)**2 < radius_squared,['x','y','z'])
if len(insink)==0:
return insink
cm=s.position*s.mass
p=s.velocity*s.mass
s.mass+=insink.total_mass()
s.position=(cm+insink.center_of_mass()*insink.total_mass())/s.mass
s.velocity=(p+insink.total_momentum())/s.mass
all_lost_particles.add_particles(insink)
return all_lost_particles
def main(N, Mtot, Rvir, rsink):
converter=nbody_system.nbody_to_si(Mtot, Rvir)
bodies = new_plummer_gas_model(N, convert_nbody=converter)
sink = Particles(1)
sink.mass = 0 | units.MSun
sink.radius = rsink
sink.position = (0, 0, 0) | units.AU
sink.velocity = (0, 0, 0) | units.kms
accreted = hydro_sink_particles(sink, bodies)
print "Particles in sink: N=", len(accreted), " M=", sink.mass
print "sink position=", sink.position.as_quantity_in(units.AU)
print "sink velocity=", sink.velocity.as_quantity_in(units.kms)
def new_option_parser():
from amuse.units.optparse import OptionParser
result = OptionParser()
result.add_option("-N", dest="N", type="int",default = 100,
help="number of sph particles [100]")
result.add_option("-M", unit=units.MSun,
dest="Mtot", type="float", default = 1|units.MSun,
help="Mass of molcular cloud [%default]")
result.add_option("-R", unit=units.AU,
dest="Rvir", type="float", default = 100|units.AU,
help="Radius of cloud [%default]")
result.add_option("-r", unit=units.AU,
dest="rsink", type="float", default = 100|units.AU,
help="Radius of the sink [%default]")
return result
if __name__ in ('__main__', '__plot__'):
o, arguments = new_option_parser().parse_args()
main(**o.__dict__)
Keywords: python, amuse, astrophysics, matplotlib, pylab, example, codex (see how-to-search-examples)