View source for Fluidics

{{Short description|Use of a fluid to perform analog or digital operations}}
{{Use dmy dates|date=August 2019|cs1-dates=y}}
[[File:Fluidic AND XOR.svg|thumb|A module with two input streams at the top, an [[AND gate|AND]] output bucket in the middle, and an [[XOR gate|XOR]] output stream at the bottom.]]
'''Fluidics''', or '''fluidic logic''', is the use of a [[fluid]] to perform [[analog signal|analog]] or [[Digital data|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 cylinder]]s 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 [[nonlinearity|nonlinear]] [[amplifier|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.
== History ==
In 1920, Nikola Tesla patented a valvular conduit or [[Tesla valve]] that works as a fluidic diode. It was a leaky diode, i.e. the reverse flow is non-zero for any applied pressure difference. Tesla's valve also had non-linear response, as its diodicity had frequency dependence. It could be used in fluid circuits, such as a full-wave rectifier, to convert AC to DC.<ref>{{cite journal|last1=Nguyen|first1=Quynh|last2=Abouezzi|first2=Joanna|last3=Ristroph|first3=Leif|title=Early turbulence and pulsatile flows enhance diodicity of Tesla's macrofluidic valve|journal= Nature Communications| issue =12 |pages=2884|date=17 May 2021|volume=12 |doi=10.1038/s41467-021-23009-y|pmid=34001882 |pmc=8128925  |arxiv=2103.17222 |bibcode=2021NatCo..12.2884N |doi-access=free}}</ref>
In 1957, Billy M. Horton of the [[Harry Diamond Laboratories]] (which later became a part of the [[United States Army Research Laboratory|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]].<ref>{{Cite book |url=https://books.google.com/books?id=T3n2uogTAqwC&pg=PA28 |title=Encyclopedia of Chemical Processing and Design: Volume 23 – Fluid Flow |author-last=McKetta |author-first=John |publisher=CRC Press |date=1985-11-21 |isbn=9780824724733 |pages=28}}</ref> 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.<ref>{{Cite magazine |author-last=Bradbury |author-first=Wilbur |date=1967-05-19 |editor-last=Luce |editor-first=Henry |title=Overdue Idea Put on a Scratch Pad |url=https://books.google.com/books?id=TVYEAAAAMBAJ&pg=PA115 |magazine=[[Life (magazine)|Life]] |publisher=[[Time (magazine)|Time]] |pages=115–116}}</ref> Their published result caught the attention of several major industries and created a surge of interest in applying fluidics (then called fluid amplification) to sophisticated control systems, which lasted throughout the 1960s.<ref>{{Cite journal |url=https://apps.dtic.mil/sti/citations/ADA134046 |archive-url=https://web.archive.org/web/20211211013402/https://www.dtic.mil/docs/citations/ADA134046 |url-status=live |archive-date=11 December 2021 |title=Fluidics: Basic Components and Applications |author-last=Joyce |author-first=James W. |date=August 1983 |location=Maryland |website=Defense Technical Information Center |access-date=2018-07-10}}</ref><ref>{{Cite journal |author-last=Gottron |author-first=R. |author-last2=Kumar |author-first2=V. |author-last3=Corrado |author-first3=A. |date=August 1975 |title=Fluidic Applications in North America |journal=IFAC Proceedings Volumes |volume=8 |issue=1 |pages=531–538 |doi=10.1016/S1474-6670(17)67511-6|doi-access=free }}</ref> Horton is credited for developing the first fluid amplifier control device and launching the field of fluidics.<ref>{{Cite journal |title=People |date=April 1975 |journal=IEEE Spectrum |volume=12 |issue=4 |pages=108–109 |doi=10.1109/MSPEC.1975.6368799 }}</ref> In 1961, Horton, Warren, and Bowles were among the 27 recipients to receive the first Army Research and Development Achievement Award for developing the fluid amplifier control device.<ref>{{Cite news |url=https://asc.army.mil/docs/pubs/alt/archives/1961/Aug_1961.PDF |title=CRD Announces Winners of 22 R&D Achievement Awards |date=August 1961 |work=Army R&D Magazine |access-date=2018-07-10 |issue=8 |volume=2}}</ref>
== Logic elements ==
[[Logic gate|Logic gates]] can be built that use water instead of electricity to power the gating function. These are reliant on being positioned in one orientation to perform correctly. An OR gate is simply two pipes being merged, and a NOT gate (inverter) consists of "A" deflecting a supply stream to produce Ā. The AND and XOR gates are sketched in the diagram. An inverter could also be implemented with the XOR gate, as A XOR 1 = Ā.<ref>{{cite web |url=http://www.blikstein.com/paulo/projects/project_water.html |title=Programmable Water: Computation is not just about electronics |author-last=Blikstein |author-first=Paulo |website=Blikstein Consultoria |publisher=Stanford University |access-date=2019-06-23}}</ref>
Another kind of fluidic logic is ''bubble logic''. Bubble logic gates conserve the number of bits entering and exiting the device, because bubbles are neither produced nor destroyed in the logic operation, analogous to [[billiard-ball computer]] gates.<ref>{{cite web |url=http://web.media.mit.edu/~manup/research/bubble-logic/ |title=Manu Prakash: Research: Bubble Logic |author-last=Prakash |author-first=Manu |date=2007-02-08 |publisher=Massachusetts Institute of Technology (MIT) |archive-url=https://web.archive.org/web/20120126042311/http://web.media.mit.edu/~manup/research/bubble-logic/ |archive-date=2012-01-26 |access-date=2019-06-23}}</ref>
== Components ==
[[File:Flow field of a fluidic oscillator.ogv|left|thumb|A video simulating the internal flow of a fluidic feedback oscillator. ]]
=== Amplifiers ===
[[File:Fluidicamplifier.svg|thumb|300px|Fluidic amplifier, showing flow in both states, from {{US patent|4000757}}.]]
In a fluidic amplifier, a fluid supply, which may be air, water, or [[hydraulic fluid]], enters at the bottom.  Pressure applied to the control ports C<sub>1</sub> or C<sub>2</sub> deflects the stream, so that it exits via either port O<sub>1</sub> or O<sub>2</sub>.  The stream entering the control ports may be much weaker than the stream being deflected, so the device has [[Gain (electronics)|gain]].
This basic device can be used to construct other fluidic logic elements, as well [[ Physics_of_whistles#Fluidic_oscillators | fluidic oscillators]] that can be used in analogous way as [[Flip-flop (electronics)|flip flops]].<ref>{{Cite journal|last1=Tesař|first1=Václav|date=2019-08-09|title=Time-Delay Circuits for Fluidic Oscillators and Pulse Shapers|journal=Energies|language=en|volume=12|issue=16|pages=3071|doi=10.3390/en12163071|issn=1996-1073|doi-access=free}}</ref> Simple systems of digital logic can thus be built.
Fluidic amplifiers typically have bandwidths in the low [[kilohertz]] range, so systems built from them are quite slow compared to electronic devices.
=== Triodes ===
The fluidic [[triode]], an [[amplifier|amplification]] device that uses a [[fluid]] to convey the [[signal (information theory)|signal]], has been invented, as have fluid diodes, a fluid oscillator and a variety of hydraulic "circuits," including one that has no electronic counterpart.<ref>{{Cite magazine|last1=Stong|first1=C. L.|date=August 1962|title=The Amateur Scientist. How streams of water can be used to create analogues of electronic tubes and circuits|url=https://www.scientificamerican.com/article/the-amateur-scientist-1962-08/|magazine=Scientific American|pages=128–138|access-date=2020-04-28}}</ref>
== Uses ==
The [[MONIAC Computer]] built in 1949 was a fluid-based [[Analog computer|analogue computer]] used for teaching economic principles as it could recreate complex simulations that digital computers could not at the time. Twelve to fourteen were built and acquired by businesses and teaching establishments.
The FLODAC Computer was built in 1964 as a proof of concept fluid-based [[digital computer]].<ref>{{Cite web |title=Proceedings – Fall Joint Computer Conference |date=1964 |url=https://www.computer.org/csdl/proceedings/afips/1964/5065/00/50650631.pdf |pages=631–641}}</ref>
Fluidic components appear in some hydraulic and pneumatic systems, including some automotive [[automatic transmission]]s. As electronic [[digital logic]] has become more accepted in industrial control, the role of fluidics in industrial control has declined.
In the consumer market, fluidically controlled products are increasing in both popularity and presence, installed in items ranging from toy spray guns through shower heads and hot tub jets; all provide oscillating or pulsating streams of air or water. Logic-enabled textiles for applications in [[wearable technology]] has also been researched.<ref>{{Cite journal |last1=Rajappan |first1=Anoop |last2=Jumet |first2=Barclay |last3=Shveda |first3=Rachel A. |last4=Decker |first4=Colter J. |last5=Liu |first5=Zhen |last6=Yap |first6=Te Faye |last7=Sanchez |first7=Vanessa |last8=Preston |first8=Daniel J. |date=2022-08-30 |title=Logic-enabled textiles |journal=Proceedings of the National Academy of Sciences |language=en |volume=119 |issue=35 |pages=e2202118119 |doi=10.1073/pnas.2202118119 |doi-access=free |issn=0027-8424 |pmc=9436326 |pmid=35994641|bibcode=2022PNAS..11902118R }}</ref>
Fluid logic can be used to create a [[valve]] with no moving parts such as in some [[anaesthetic machine]]s.<ref>{{Cite journal|last1=Meyer|first1=James A.|last2=Joyce|first2=James W.|date=1968|title=The Fluid Amplifier and its Application in Medical Devices|journal=Anesthesia & Analgesia|volume=47|issue=6|pages=710–716|doi=10.1213/00000539-196811000-00015|pmid=5247311|s2cid=28322668}}</ref>
Fluidic oscillators were used in the design of pressure-triggered, [[3D printing|3D printable]], emergency ventilators for the [[COVID-19 pandemic]].<ref>{{Cite web|url=https://3dprintedventilator.com/|title=3D-printed open source ventilator for medical purposes|access-date=2020-04-28}}</ref><ref>{{Cite web|url=https://worldwideventilator.com/|title=Worldwide Ventilator|access-date=2020-04-28}}</ref><ref>{{Cite web|url= https://3dprintingindustry.com/news/volunteers-develop-3d-printable-ventilator-based-on-1965-u-s-army-design-170653/|title=Volunteers develop 3D printable ventilator based on 1965 usarmy design|date=9 April 2020|access-date=2020-04-28}}</ref>
Fluidic amplifiers are used to generate ultrasound for non-destructive testing by quickly switching pressurized air from one outlet to another.<ref>{{Cite journal|last1=Bühling|first1=Benjamin|last2=Strangfeld|first2=Christoph|last3=Maack|first3=Stefan|last4=Schweitzer|first4=Thorge|date=2021-04-01|title=Experimental analysis of the acoustic field of an ultrasonic pulse induced by a fluidic switch|journal=The Journal of the Acoustical Society of America|volume=149|issue=4|pages=2150–2158|doi=10.1121/10.0003937|pmid=33940860|bibcode=2021ASAJ..149.2150B|s2cid=233568721 |issn=0001-4966|doi-access=free}}</ref>
A fluidic sound ampliflication system has been demonstrated in a synagogue, where regular electronic sound amplification can not be used for religious reasons.<ref>{{cite web |title=Acousto-Fluidic Sound Augmentation for Orthodox Jewish Worship Spaces |url=https://acoustics.org/pressroom/httpdocs/132nd/2aaa8.html |access-date=23 April 2024 |first=Tadeusz M. |last=Drzewiecki |date=3 December 1996 |publisher=Acoustical Society of America |website=Acoustics Lay Language Papers}}</ref><ref>{{cite web |url=https://www.technologyreview.com/1997/02/01/41630/kosher-sound/ |title=Kosher Sound |first=Steven |last=Strauss |date=February 1, 1997 |access-date=23 April 2024 |website=MIT Technology Review}}</ref>
Fluidic injection is being researched for use in [[aircraft]] to control direction, in two ways: ''circulation control'' and ''thrust vectoring''. In both, larger more complex mechanical parts are replaced by fluidic systems, in which larger forces in fluids are diverted by smaller jets or flows of fluid intermittently, to change the direction of vehicles. In circulation control, near the trailing edges of wings, [[aircraft flight control system]]s such as [[aileron]]s, [[Elevator (aircraft)|elevators]], [[elevon]]s, [[Flap (aircraft)|flaps]], and [[flaperon]]s are replaced by openings, usually rows of holes, or elongated slots, which emit fluid flows.<ref>{{cite journal |author-first=P. |author-last=John |title=The flapless air vehicle integrated industrial research (FLAVIIR) programme in aeronautical engineering |journal=Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering |volume=224 |issue=4 |pages=355–363 |location=London |publisher=Mechanical Engineering Publications |date=2010 |url=http://journals.pepublishing.com/content/m9r3684g2874w026/ |archive-url=https://web.archive.org/web/20180517223645/http://journals.pepublishing.com/content/m9r3684g2874w026 |url-status=dead |archive-date=2018-05-17 |issn=0954-4100 |doi=10.1243/09544100JAERO580 |hdl=1826/5579|s2cid=56205932 |hdl-access=free }}</ref><ref>{{Cite web |title=Showcase UAV Demonstrates Flapless Flight |publisher=BAE Systems |date=2010 |url=http://www.baesystems.com/AboutUs/ShowcaseUAVDemonstratesFlaplessFlight/ |access-date=2010-12-22 |archive-url=https://web.archive.org/web/20110707205548/http://www.baesystems.com/AboutUs/ShowcaseUAVDemonstratesFlaplessFlight/ |archive-date=2011-07-07 |url-status=dead}}</ref><ref>{{cite news |title=Demon UAV jets into history by flying without flaps |newspaper=Metro.co.uk |publisher=Associated Newspapers Limited |location=London |date=2010-09-28 |url=http://www.metro.co.uk/news/842292-plane-jets-into-history-by-flying-without-flaps}}</ref> In [[thrust vectoring]], in [[jet engine]] nozzles, swiveling parts are replaced by openings which inject fluid flows into jets.<ref name="Skewing">{{cite journal |author-last1=Yagle |author-first1=P. J. |author-last2=Miller |author-first2=D. N. |author-last3=Ginn |author-first3=K. B. |author-last4=Hamstra |author-first4=J. W. |title=Demonstration of Fluidic Throat Skewing for Thrust Vectoring in Structurally Fixed Nozzles |journal=Journal of Engineering for Gas Turbines and Power |volume=123 |issue=3 |pages=502–508 |date=2001 |url=http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000123000003000502000001 |doi=10.1115/1.1361109}}</ref> Such systems divert thrust via fluid effects. Tests show that air forced into a jet engine exhaust stream can deflect thrust up to 15 degrees.<ref name="Skewing"/> In such uses, fluidics is desirable for lower: mass, cost (up to 50% less), drag (up to 15% less during use), [[inertia]] (for faster, stronger control response), complexity (mechanically simpler, fewer or no moving parts or surfaces, less maintenance), and [[radar cross section]] for [[stealth technology|stealth]].<ref>{{cite news |last=Uppal |first=Rahesh |date=3 March 2022 |url=https://idstch.com/military/air/active-flow-control-for-stealth-aircrafts-and-drones/ |title=Active Flow Control for Stealth Aircraft and Drones |website=International Defense, Security & Technology (IDST) |access-date=30 May 2023}}</ref><ref>{{cite AV media |author=<!-- Unstated --> |date=3 August 2018 |title=Making aircraft less detectable |type=video |language=en |url=https://m.youtube.com/watch?v=ruSQa1PvC3E |access-date=30 May 2023 |location=Europe, United States |publisher=North Atlantic Treaty Organization (NATO)}}</ref> This will likely be used in many [[unmanned aerial vehicle]]s (UAVs), 6th generation [[fighter aircraft]], and [[ship]]s.
{{As of|2023}}, at least two countries are known to be researching fluidic control. In Britain, [[BAE Systems]] has tested two fluidically controlled unmanned aircraft, one starting in 2010 named [[BAE Systems Demon|Demon]],<ref name="UAV2010">{{cite web |url=https://arstechnica.com/science/2010/10/new-test-plane-flies-without-flaps/ |title=New test plane flies without control surfaces |author-last=Christopher |author-first=Dombrowski |date=2010-10-05 |website=Ars Technica |publisher=Wired Media Group |access-date=2019-06-21}}</ref><ref name="NatInt2019">{{cite web |url=https://nationalinterest.org/blog/buzz/f-22-and-b-2-bomber-are-old-new-generation-super-stealth-coming-44422 |title=The F-22 and B-2 Bomber Are Old: A New Generation of Super Stealth Is Coming |author-last=Axe |author-first=David |date=2019-02-13 |website=The National Interest |publisher=Center for the National Interest |access-date=2019-06-21}}</ref> and another starting in 2017 named MAGMA, with the [[University of Manchester]].<ref name="UAV2017">{{cite web |url=https://www.baesystems.com/en/article/first-magma-flight-trials |title=Successful first flight trial completion of unmanned aerial vehicle, MAGMA |author=<!--Unstated--> |date=2017-12-13 |website=BAE Systems |access-date=2019-06-21}}</ref> In the United States, the ''Defense Advanced Research Projects Agency'' ([[DARPA]]) program named ''Control of Revolutionary Aircraft with Novel Effectors'' (CRANE) seeks "... to design, build, and flight test a novel X-plane that incorporates active flow control (AFC) as a primary design consideration. ... In 2023, the aircraft received its official designation as X-65."<ref>{{Cite web |last=Wlezien |first=Richard |date=<!-- Undated --> |url=https://www.darpa.mil/program/control-of-revolutionary-aircraft-with-novel-effectors |title=Control of Revolutionary Aircraft with Novel Effectors (CRANE) |website=Defense Advanced Research Projects Agency ([[DARPA]]) |access-date=4 October 2023}}</ref><ref>{{Cite news |last=Trimble |first=Steve |date=16 May 2023 |url=https://aviationweek.com/defense-space/aircraft-propulsion/darpa-receives-x-65-designation-active-flow-experiment |title=DARPA Receives X-65 Designation for Active Flow Experiment |work=[[Aviation Week & Space Technology]] |access-date=4 October 2023}}</ref> In winter 2024, construction began, at [[Boeing]] subsidiary [[Aurora Flight Sciences]].<ref name="AFS">{{Cite press release |last=Smith |first=Carmen |date=3 January 2024 |url=https://www.aurora.aero/2024/01/03/aurora-begins-building-full-scale-active-flow-control-x-plane/ |title=Aurora Begins Building Full-Scale Active Flow Control X-Plane |website=[[Aurora Flight Sciences]], [[Boeing]] |access-date=1 February 2024}}</ref> In summer 2025, flight testing is to start.<ref name="AFS"/>
[[Octobot (robot)|Octobot]], a 2016 [[proof of concept]] [[Soft robotics|soft-bodied]] [[autonomous robot]] containing a [[microfluidic]] [[logic circuit]], has been developed by researchers at [[Harvard University]]'s [[Wyss Institute for Biologically Inspired Engineering]].<ref>{{cite web |url=https://wyss.harvard.edu/the-first-autonomous-entirely-soft-robot/ |title=The first autonomous, entirely soft robot |author-last=Burrows |author-first=Leah |date=2016 |access-date=2019-06-12}}</ref>
== See also ==
* [[Water integrator]]
* [[Microfluidics]]
* [[Bio-MEMS]]
* [[Lab-on-a-chip]]
* [[MONIAC]]
* [[Unconventional computing]]
== References ==
{{Reflist}}
== Further reading ==
* {{cite book |author-first=Charles A. |author-last=Belstirling |title=Fluidic Systems Design |url=https://archive.org/details/BELSTERLINGFluidicSystemsDesign1971 |date=1971 | publisher=Wiley}}
* {{Cite journal |author-last=Lal |author-first=Jagdish |title=Hydraulics |publisher=Metropolitan Book |date=1963 |asin=B0007IWSX2 }}
* {{Cite journal |author=O. Lew wood |title=Pure Fluid Device |journal=[[Machine Design]] |date=June 1964 |pages=154–180}}
* {{Cite journal |author-last1=Tarumoto |author-first1=E. F. |author-last2=Humphrey |author-first2=D. H. |title=Fluidics |publisher=Fluid Amplifier Associates, Inc. |date=1965 |asin=B000HBV114 }}
* {{Cite journal |author-last1=Bowles |author-first1=R. E. |author-last2=Dexter |author-first2=E. M. |title=A second Generation of Fluid System Application |publisher=Fluid Amplification Symposium |date=October 1965 |pages=213}}
* {{cite book |author-first=Ernest C. |author-last=Fitch, Jr. |title=Fluid Logic |date=1966 |publisher=[[Oklahoma State University]]}}
* {{cite book |author-last=Brown |author-first=Forbes T. |date=1967 |title=Advances in Fluidics |publisher=The American Society of Mechanical Engineers |asin=B000I3ZC7K }}
* {{cite book |author-last=Foster |author-first=Kenneth |date=1970 |title=Fluidics: Components and Circuits |publisher=John Wiley & Sons |isbn=9780471267706}}
* {{Cite journal |author-last=Lal |author-first=Jagdish |title=Hydraulic Machines |publisher=Metropolitan Book |date=1975 |asin=B000HBV114 }}
* {{cite book |editor-last=Conway |editor-first=Arthur |date=1971 |title=A Guide to Fluidics |publisher=American Elsevier |isbn=978-0-44419601-9}}
* {{US patent|3417770}}
* {{US patent|3495253}}
* {{US patent|3503410}}
* {{US patent|3612085}}
* {{US patent|4854176}}
* FLODAC – A Pure Fluid Digital Computer: {{US patent|3190554}}
* Stanley W. Angrist: ''Fluid control devices.'' In: ''Scientific American'', December 1964, pp.&nbsp;80–88. [http://miriam-english.org/files/fluidics/FluidControlDevices.html]
* {{Cite journal |author=O. Lew wood |title=Pure Fluid Device |journal=[[Machine Design]] |date=June 1964 |pages=154–180}}
* [http://members.chello.at/karl.bednarik/FLUIDIK2.jpg Pneumatic logic elements from 1969]
== External links ==
{{commons category}}
* [https://books.google.com/books?id=jSEDAAAAMBAJ&lpg=PA197 Fluidics: How They've Taught A Stream of Air to Think pp.&nbsp;118–121,196.197, illustrating several switch designs and discussing applications. Scanned article available online from Google Books: ''Popular Science'' June 1967]
*[https://www.youtube.com/watch?v=TgYJ1Ni08UA Visualization of the flow field of a fluidic oscillator]
{{emerging technologies|topics=yes|robotics=yes|manufacture=yes|materials=yes}}
[[Category:Fluid dynamics]]
[[Category:Logic]]