Individual #hydrodynamics__hydrodynamic__hydrokinetics__hydrokinetic  study of fluids in motion
  >part:  #magnetohydrodynamics  the study of the interaction of magnetic fields and electrically conducting fluids (as plasma or molten metal)
  >part of:  #fluid_mechanics__fluidmechanic__hydraulics  study of the mechanics of fluids
     >part of:  #mechanics__mechanic  the branch of physics concerned with the motion of bodies in a frame of reference
        >part of:  #physics__physic__physical_science__natural_philosophy__naturalphilosophy  the science of matter and energy and their interactions

No statement uses or specializes #hydrodynamics; click here to add one.