Hydrodynamics of Clustered Clouds: Drafting, Survival, Condensation, and
  Ablation
  For et al., who catalogued Magellanic Stream (MS) clouds, suggested that
there is substantial large-scale turbulence in the MS. Here we follow up with a
series of FLASH simulations that model the hydrodynamic effects that clouds
have on each other. The suite of simulations includes a range of cloud
separation distances and densities. The ambient conditions are similar to those
surrounding the MS but also relevant to the circumgalactic medium and
intergalactic medium. Ten simulations are presented, eight of which model
clustered clouds and two of which model isolated clouds. The isolated clouds
are used as controls for comparison with the multicloud simulations. We find
that if the clouds are initially near each other, then hydrodynamical drafting
helps the trailing cloud to catch the leading cloud and mix together. We
present the measured acceleration due to drafting and find that lower-density
clouds in lower-density environments experience more acceleration due to
drafting than their denser cohorts. We find that the clustering of clouds also
increases the condensation of ambient material and affects longevity. We
analyze the velocity dispersion of the clouds using a single component method
and a multicomponent decomposition method. We find that the presence of a
second cloud increases the velocity dispersion behind the trailing cloud at
some times. We find that the velocity dispersion due to gas motion in our
simulations is significantly less than the actual dispersion observed by For et
al., indicating that the thermal component must dominate in the MS.
