Implosion is a process in which objects are destroyed by collapsing in on themselves. The opposite of explosion, implosion concentrates matter and energy. An example of implosion is a submarine being crushed from the outside by the high pressure of the surrounding water.

In an implosion-type nuclear weapon design, a sphere of plutonium, uranium, or other material is imploded by a spherical arrangement of explosive charges, increasing the density by a factor 2 to 4, making the mass critical, resulting in a nuclear explosion. In a thermonuclear weapon, the energy from this explosion is then used to implode a capsule of fusion fuel before igniting it, causing a fusion reaction (see Teller–Ulam design).

In the context of cavitation, implosion is a suctional process that causes matter to move inwards, not outwards as is the case with explosion. This inward (centripetal) motion, however, does not follow a straight (radial) path to the centre; it follows a spiralling, whirling path. This is called a vortex. In cavitation, a number of small bubbles of water vapor are created by the low pressure on one side of a propellor. When these bubbles collapse they can produce intense local shock waves which create noise and can cause local failure at the propellor's surface, a process leading to material erosion.

A very characteristic feature of a vortex is that the outside of the vortex moves slowly and the centre moves fast. As water is imploded in a vortex, suspended particles, which are denser than water, are sucked into the centre of flow, frictional resistance is reduced and the speed of the flow is increased.

See also

• Building implosion

External links

• Converging Shock Waves

Mechanics

Implosion Implosión | درون‌پاشی | Имплозија | Implosie | Implozja (fizyka) | Imploosio | Implosion