Inertial waves, also known as
inertial oscillations, are a type of
mechanical wave possible in rotating
fluids. Unlike
surface gravity waves commonly seen at the beach or in the bathtub, inertial waves travel through the interior of the fluid, not at the surface. Like any other kind of wave, an inertial wave is caused by a
restoring force and characterized by its
wavelength and
frequency. Because the restoring force for inertial waves is the
Coriolis force, their wavelengths and frequencies are related in a peculiar way. Inertial waves are
transverse. Most commonly they are observed in atmospheres, oceans, lakes, and laboratory experiments.
Rossby waves,
geostrophic currents, and
geostrophic winds are examples of inertial waves. Inertial waves are also likely to exist in the core of the
Earth.