Whispering-gallery waves for sound exist in a wide variety of systems.
At first sight, it seems that such a wave should not exist.
A tropical wave existed Africa on September 1, and after initial development became disorganized.
We know that such waves exist, but we have never been able to study them, here on Earth.
The goal was to see if these waves existed, and examine how they might influence ship and offshore platform design.
Without it, the string would not vibrate, and no wave could exist.
In free space, an inertial wave can exist at any frequency between 0 and twice the rotation rate.
Such waves exist only in cases of space with odd dimensions.
In principle, gravitational waves could exist at any frequency.
I still don't know if the fourth wave ever existed.