We present three-dimensional, high-resolution hydrodynamical simulations of
the interaction between the hot ionized intracluster medium and the cold i
nterstellar medium of spiral galaxies. Ram pressure and turbulent/viscous s
tripping remove 100% of the atomic hydrogen content of Luminous galaxies li
ke the Milky Way within 100 million years. These mechanisms naturally accou
nt for the morphology of SO galaxies and the rapid truncation of star forma
tion implied by spectroscopic observations, as well as a host of observatio
nal data on the neutral hydrogen (HI) morphology of galaxies in clusters.