Sound out the obstacle
Sonar is an American acronym for SOund, NAvigation and Ranging, initially used during World War II to refer to ultrasound detection of underwater objects. It was the first major application of the piezoelectric effect (the ability of some materials, notably crystals and certain ceramics, to generate an electric potential in response to applied mechanical stress). Sonar depends on transmitted and reflected sound waves to measure underwater distances for detecting and fixing the precise location of submerged objects. Lewis Nixon invented the first sonarlike listening device in 1906 to detect icebergs but it was passive (no signals were sent out). By 1918, both Britain and the US had built active systems that could both send and receive signals for detecting submarines. The sound data, which are typically relayed by monitor display, have since been found useful for functions other than submarine and mine detection, such as depth sounding, commercial fishing, diving safety, and communications at sea. The invention of the acoustic transducer and an efficient acoustic projector made more advanced forms of sonar possible.

PZFlex has been used extensively in the design of sonar arrays for mine hunting and the underwater detection and evaluation of surface ships and submarines. Dependence on substantial submarine fleets is a key factor in sonar’s remaining a top priority for major world powers. PZFlex was substantially improved by its support of research sponsored by the US and UK naval departments and by sonar manufacturers. The specialized manner in which the software was implemented facilitates solving large numerical giving designers valuable insight into sonar’s theoretical capabilities.