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A bow wave is the
The size of the bow wave is a function of the speed of the ship, its draft,
Bow waves - Feynman Lectures on Physics
Naval architecture Fluid dynamics Water waves {{navy-stub
wave
In physics, mathematics, and related fields, a wave is a propagating dynamic disturbance (change from equilibrium) of one or more quantities. Waves can be periodic, in which case those quantities oscillate repeatedly about an equilibrium (re ...
that forms at the bow of a ship when it moves through the water. As the bow wave spreads out, it defines the outer limits of a ship's wake. A large bow wave slows the ship down, is a risk to smaller boats, and in a harbor can damage shore facilities and moored ships. Therefore, ship hulls are generally designed to produce as small a bow wave as possible.
Description
The size of the bow wave is a function of the speed of the ship, its draft, surface wave
In physics, a surface wave is a mechanical wave that propagates along the interface between differing media. A common example is gravity waves along the surface of liquids, such as ocean waves. Gravity waves can also occur within liquids, at ...
s, water depth, and the shape of the bow. A ship with a large draft and a blunt bow will produce a large wave, and ships that plane over the water surface will create smaller bow waves. Bow wave patterns are studied in the field of computational fluid dynamics
Computational fluid dynamics (CFD) is a branch of fluid mechanics that uses numerical analysis and data structures to analyze and solve problems that involve fluid flows. Computers are used to perform the calculations required to simulate ...
.
The bow wave carries energy away from the ship at the expense of its kinetic energy—it slows the ship. A major goal of naval architecture
Naval architecture, or naval engineering, is an engineering discipline incorporating elements of mechanical, electrical, electronic, software and safety engineering as applied to the engineering design process, shipbuilding, maintenance, and ...
is therefore to reduce the size of the bow wave and improve the ship's fuel economy. Modern ships are commonly fitted with a bulbous bow to achieve this.
A bow wave forms at the head of a swimmer
Swimming is an individual or team racing sport that requires the use of one's entire body to move through water. The sport takes place in pools or open water (e.g., in a sea or lake). Competitive swimming is one of the most popular Olympic ...
moving through water. The trough of this wave
In physics, mathematics, and related fields, a wave is a propagating dynamic disturbance (change from equilibrium) of one or more quantities. Waves can be periodic, in which case those quantities oscillate repeatedly about an equilibrium (re ...
is near the mouth of the swimmer and helps the swimmer to inhale air to breathe just by turning their head.
A similar thing occurs when an airplane travels at the speed of sound. The overlapping wave crests disrupt the flow of air over and under the wings. Just as a boat can easily travel faster than the wave it produces, an airplane with sufficient power can travel faster than the speed of sound (supersonic).
See also
* Kelvin wake pattern *Shock wave
In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a me ...
* Bow shock (aerodynamics)
* Bulbous bow
References
External links
Bow waves - Feynman Lectures on Physics
Naval architecture Fluid dynamics Water waves {{navy-stub