Fluidics

Fluidics, or fluidic logic, is the use of a fluid to perform analog or digital operations similar to those performed with electronics. The physical basis of fluidics is pneumatics and hydraulics, based on the theoretical foundation of fluid dynamics. The term fluidics is normally used when devices have no moving parts, so ordinary hydraulic components such as hydraulic cylinders and spool valves are not considered or referred to as fluidic devices. A jet of fluid can be deflected by a weaker jet striking it at the side. This provides nonlinear amplification, similar to the transistor used in electronic digital logic. It is used mostly in environments where electronic digital logic would be unreliable, as in systems exposed to high levels of electromagnetic interference or ionizing radiation. Nanotechnology considers fluidics as one of its instruments. In this domain, effects such as fluid–solid and fluid–fluid interface forces are often highly significant. Fluidics have also been used for military applications. In 1920, Nikola Tesla patented a valvular conduit or Tesla valve that works as a fluidic diode. It's a leaky diode, i.e. the reverse flow is non-zero for any applied pressure difference. Tesla valve also has non-linear response, as it diodicity has frequency dependence. It could be used in fluid circuits, such as a full-wave rectifier, to convert AC to DC. In 1957, Billy M. Horton of the Harry Diamond Laboratories (which later became a part of the Army Research Laboratory) first came up with the idea for the fluidic amplifier when he realized that he could redirect the direction of flue gases using a small bellows. He proposed a theory on stream interaction, stating that one can achieve amplification by deflecting a stream of fluid with a different stream of fluid. In 1959, Horton and his associates, Dr. R. E. Bowles and Ray Warren, constructed a family of working vortex amplifiers out of soap, linoleum, and wood.