The Collaborative International Dictionary of English v.0.48:

Hydromechanics \Hy`dro*me*chan"ics\, n. [Hydro-, 1 + mechanics.]
   That branch of physics which treats of the mechanics of
   liquids, or of their laws of equilibrium and of motion.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "hydromechanics":
   aeromechanics, animal mechanics, biomechanics, celestial mechanics,
   electromechanics, fluid mechanics, fluidics, hydraulics,
   hydrodynamics, hydrography, hydrology, hydrometry, hydrostatics,
   leverage, mechanical arts, mechanics, quantum mechanics,
   rational mechanics, servomechanics, statistical mechanics,
   wave mechanics, zoomechanics