Yes, sound waves do travel through water. In fact, water is an excellent medium for transmitting sound due to its density and molecular structure. Sound waves are mechanical vibrations that propagate through a medium by displacing particles back and forth. In water, these vibrations can travel over long distances and at high speeds.
However, the notion that water needs to be flat for sound waves to travel through it is not accurate. Sound waves can propagate through water regardless of its surface condition. The flatness of the water's surface does not significantly affect the transmission of sound waves through the water column.
The misconception may stem from the fact that surface waves, such as ripples or waves caused by wind, can disrupt the smoothness of the water's surface. These surface waves can cause reflections, refractions, and diffractions that affect the propagation of sound waves at the water-air interface. This interference can make it more challenging to detect or interpret underwater sounds, particularly in certain marine applications or sonar systems.
However, below the water's surface, sound waves can travel through water without any dependence on the surface's flatness. Sound can propagate through water even if the surface is disturbed or turbulent.