FredT
Guest
Wave length is defined by the wave period.
L= 5.12T^2
Water depth where the wave starts to significantly feel the bottom is at approximately half the wave length.
As an example a 6 second wave starts to feel bottom in 92 feet of water while a 16 second wave starts to feel bottom in 655 feet of water.
Speed of the water particles and orbit size is approximately halved for every 1/9 wavelength in depth. A 10' wave with 12 second period has a surface particle circle of 10' in diameter and a wavelength of 1000 ft. At 111 feet (1/9*L) the particle motion of the wave is decreased so the particle motion circle is now 5'. If the bottom is close the circular wave motion is compressed into a elipse with a similar although slightly smaller internal area. This flattened wave particle motion is what divers feel as "surge".
FT
L= 5.12T^2
Water depth where the wave starts to significantly feel the bottom is at approximately half the wave length.
As an example a 6 second wave starts to feel bottom in 92 feet of water while a 16 second wave starts to feel bottom in 655 feet of water.
Speed of the water particles and orbit size is approximately halved for every 1/9 wavelength in depth. A 10' wave with 12 second period has a surface particle circle of 10' in diameter and a wavelength of 1000 ft. At 111 feet (1/9*L) the particle motion of the wave is decreased so the particle motion circle is now 5'. If the bottom is close the circular wave motion is compressed into a elipse with a similar although slightly smaller internal area. This flattened wave particle motion is what divers feel as "surge".
FT