How does gravity affect hydrodynamics?

The ocean's surface is an example of a fluid interface where gravity waves are created. Wind generates ripples, which spread. Gravity waves are transverse waves, and the water's surface moves vertically on a horizontal plane.

In the linearized approximation of Einstein's equations, gravitational waves are generated when two massive objects, such as stars, accelerate in each other's gravitational field. These waves in spacetime cause test particles forming a circle to be squeezed in one direction before the other, oscillating between ellipses along the x then the y axis.

The behavior of water bodies on Earth's surface, such as rivers, lakes, and oceans, is shaped by gravity, which also influences processes like tides and currents. Gravity effects fluid flow by affecting the pressure distribution in a fluid, causing variations in velocity and direction, leading to phenomena like buoyancy, sedimentation, and circulation patterns.