Transonic: Difference between revisions
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[[File:Shock wave above airliner wing (7).jpg|thumb|Shock waves may appear as weak optical disturbances above airliners with supercritical airfoil|supercritical wings]] | [[File:Shock wave above airliner wing (7).jpg|thumb|Shock waves may appear as weak optical disturbances above airliners with supercritical airfoil|supercritical wings]] | ||
[[File:Transonic flow patterns.svg|right|thumb|Transonic flow patterns on an airfoil showing flow patterns at and above critical Mach number]] | [[File:Transonic flow patterns.svg|right|thumb|Transonic flow patterns on an airfoil showing flow patterns at and above critical Mach number]] | ||
'''Transonic''' (or '''transsonic''') flow is air flowing around an object at a speed that generates regions of both subsonic and [[Supersonic speed|supersonic]] airflow around that object.<ref name=":2" /> The exact range of speeds depends on the object's [[critical Mach number]], but transonic flow is seen at flight speeds close to the [[speed of sound]] (343 m/s at sea level), typically between [[Mach number|Mach]] 0.8 and 1.2.<ref name=":2">{{Cite book|last=Anderson|first=John D. Jr. |url=https://www.worldcat.org/oclc/927104254|title=Fundamentals of aerodynamics|date=2017|isbn=978-1-259-12991-9|edition=Sixth|location=New York, NY|pages=756–758|oclc=927104254}}</ref> | |||
The issue of transonic speed (or transonic region) first appeared during World War II.<ref name=":0">{{Cite journal|last1=Vincenti|first1=Walter G.|last2=Bloor|first2=David|date=August 2003|title=Boundaries, Contingencies and Rigor|url=http://dx.doi.org/10.1177/0306312703334001|journal=Social Studies of Science|volume=33|issue=4|pages=469–507|doi=10.1177/0306312703334001|s2cid=13011496|issn=0306-3127}}</ref> Pilots found as they approached the sound barrier the airflow caused aircraft to become unsteady.<ref name=":0" /> Experts found that [[shock wave]]s can cause large-scale [[Flow separation|separation]] downstream, increasing drag, adding asymmetry and unsteadiness to the flow around the vehicle.<ref name=":1">{{Cite book|last=Takahashi|first=Timothy|url=http://worldcat.org/oclc/1162468861|title=Aircraft performance and sizing. fundamentals of aircraft performance|date=15 December 2017|isbn=978-1-60650-684-4|pages=107|publisher=Momentum Press |oclc=1162468861}}</ref> Research has been done into weakening shock waves in transonic flight through the use of [[Anti-shock body|anti-shock bodies]] and [[supercritical airfoil]]s.<ref name=":1" /> | |||
Most modern [[jet engine|jet]] powered aircraft are engineered to operate at transonic air speeds.<ref>{{cite book |last1=Takahashi |first1=Timothy |title=Aircraft Performance and Sizing, Volume I |date=2016 |publisher=Momentum Press Engineering |location=New York City |isbn=978-1-60650-683-7|pages=10–11}}</ref> Transonic airspeeds see a rapid increase in drag from about Mach 0.8, and it is the fuel costs of the drag that typically limits the airspeed. Attempts to reduce wave drag can be seen on all high-speed aircraft. Most notable is the use of [[swept wing]]s, but another common form is a wasp-waist fuselage as a side effect of the [[Whitcomb area rule]]. | |||
[[Category:Aerodynamics]] | [[Category:Aerodynamics]] | ||
[[Category:Airspeed]] | [[Category:Airspeed]] | ||
[[Category:Aircraft performance]] | [[Category:Aircraft performance]] |
Revision as of 08:56, 10 April 2025




Transonic (or transsonic) flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object.[1] The exact range of speeds depends on the object's critical Mach number, but transonic flow is seen at flight speeds close to the speed of sound (343 m/s at sea level), typically between Mach 0.8 and 1.2.[1]
The issue of transonic speed (or transonic region) first appeared during World War II.[2] Pilots found as they approached the sound barrier the airflow caused aircraft to become unsteady.[2] Experts found that shock waves can cause large-scale separation downstream, increasing drag, adding asymmetry and unsteadiness to the flow around the vehicle.[3] Research has been done into weakening shock waves in transonic flight through the use of anti-shock bodies and supercritical airfoils.[3]
Most modern jet powered aircraft are engineered to operate at transonic air speeds.[4] Transonic airspeeds see a rapid increase in drag from about Mach 0.8, and it is the fuel costs of the drag that typically limits the airspeed. Attempts to reduce wave drag can be seen on all high-speed aircraft. Most notable is the use of swept wings, but another common form is a wasp-waist fuselage as a side effect of the Whitcomb area rule.
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