# What is the maximum speed of waves in stagnant water?

I want to learn the maximum speed conditions for a wave in a fluid. I think, Which mechanism causes this limited speed? And How? The water is an understandable example for me. By this question, I hope to understand the inhibitory mechanism of the background.

In my opinion, if the waves created by moving object are existing a Doppler Wall in front of the object, the vibrations of substances of the medium may limit the maximum speed objects according to their vibration frequency.

• In fact, maximum speed of a wave in a medium, is limited by the vibration speed of its compound particles. (with mass or massless). I' d like to learn the mechanism behind this. – Burtay Mutlu Oct 22 '18 at 10:33

In practice most waves in fluids are far slower, since their frequency and wavelength are determined by gravity, density and other mechanical properties. In deep water a wave moves with velocity $\sqrt{gL/2\pi}$ where $g$ is the surface gravity and $L$ the wavelength. Long wavelength waves such as tsunamis can move at 800 km/h, or 15% of the sound speed in seawater.
The fastest waves in water are sound waves, which are longitudinal compression waves. The speed of sound waves in water is about $1500m/s$.
The speed of sound in a fluid, in general, depends on the stiffness (compressibility, elasticity) and density of the fluid: $v=\sqrt \frac K \rho$. The bulk modulus $K$ indicates how much the fluid resists compression.