hy·dro·dy·nam·ic 
(hī′drō-dī-nămĭk) also hy·dro·dy·nam·i·cal (-ĭ-kəl)
(hī′drō-dī-nămĭk) also hy·dro·dy·nam·i·cal (-ĭ-kəl)adj.
1. Of or relating to hydrodynamics.
2. Of, relating to, or operated by the force of liquid in motion.
hy′dro·dy·nami·cal·ly adv.