  There exist many physical processes that may contribute to the driving of
turbulence in galactic disks. Some of them could drive turbulence even in the
absence of star formation. For example, hydrodynamic (HD) or
magnetohydrodynamic (MHD) instabilities, frequent mergers of small satellite
clumps, ram pressure, or infalling gas clouds. In this work we present
numerical simulations to study the interaction of compact high velocity clouds
(CHVC) with the outskirts of magnetized gaseous disks. With our numerical
simulations we show that the rain of small HVCs onto the disk is a potential
source of random motions in the outer parts of HI disks.
