Flight condition in which airflow speeds are concurrently above and below the speed of sound
For the American company, see Transonic Combustion.
Aerodynamic condensation evidences of supersonic expansion fans around a transonic F/A-18The Sears–Haack body presents a cross-sectional area variation that minimises wave drag.Shock waves may appear as weak optical disturbances above airliners with supercritical wingsTransonic 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 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.
Transonic speeds can also occur at the tips of rotor blades of helicopters and aircraft. This puts severe, unequal stresses on the rotor blade and may lead to accidents if it occurs. It is one of the limiting factors of the size of rotors and the forward speeds of helicopters (as this speed is added to the forward-sweeping [leading] side of the rotor, possibly causing localized transonics).
^ abAnderson, John D. Jr. (2017). Fundamentals of aerodynamics (Sixth ed.). New York, NY. pp. 756–758. ISBN 978-1-259-12991-9. OCLC 927104254.{{cite book}}: CS1 maint: location missing publisher (link)
^ abVincenti, Walter G.; Bloor, David (August 2003). "Boundaries, Contingencies and Rigor". Social Studies of Science. 33 (4): 469–507. doi:10.1177/0306312703334001. ISSN 0306-3127. S2CID 13011496.
^ abTakahashi, Timothy (15 December 2017). Aircraft performance and sizing. fundamentals of aircraft performance. Momentum Press. p. 107. ISBN 978-1-60650-684-4. OCLC 1162468861.
^Takahashi, Timothy (2016). Aircraft Performance and Sizing, Volume I. New York City: Momentum Press Engineering. pp. 10–11. ISBN 978-1-60650-683-7.
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...
Whitcomb and also called the transonic area rule, is a design procedure used to reduce an aircraft's drag at transonic speeds which occur between about...
the aircraft. When the aircraft speed is high enough, the tips reach transonic speeds. Shock waves form at the blade tips and sap the shaft power driving...
{\gamma +1}{\gamma -1}}} High subsonic wind tunnels (0.4 < M < 0.75) and transonic wind tunnels (0.75 < M < 1.2) are designed on the same principles as the...
at high altitudes. At transonic speeds, the flow field around the object includes both sub- and supersonic parts. The transonic period begins when first...
Transonic Combustion Inc. is a Los Angeles-based cleantech company that is developing supercritical fuel injection systems that enable injection ignition...
airfoils. Theodore von Kármán and Hugh Latimer Dryden introduced the term transonic to describe flow speeds between the critical Mach number and Mach 1 where...
such as the ends of rotor blades, reach supersonic speeds are called transonic. This occurs typically somewhere between Mach 0.8 and Mach 1.2. Sounds...
non-linear in the transonic regime, dominated by moving shock waves. Avoiding flutter is mission-critical for aircraft that fly through transonic Mach numbers...
The National Transonic Facility (NTF), also known internally as facility 1236, is a high-pressure, cryogenic, closed-circuit wind tunnel at the Langley...
causing dramatically increased drag, and, in an aircraft not designed for transonic or supersonic speeds, changes to the airflow over the flight control surfaces...
to refer to particular ranges of Mach values. This occurs because a "transonic regime" exists around M=1 where approximations of the Navier–Stokes equations...
moving at high speed through moist air, such as an aircraft flying at transonic speeds. When the localized air pressure around the object drops, so does...
improves the accuracy and speed of complex simulation scenarios such as transonic or turbulent flows. Initial validation of such software is typically performed...
The European transonic wind tunnel (ETW) is a high-Reynolds-number transonic wind tunnel using nitrogen as the test gas. It is one of the world's largest...
is transonic or faster, therefore most jet aircraft need to fly at high speeds, either supersonic or speeds just below the speed of sound ("transonic")...
an airfoil designed primarily to delay the onset of wave drag in the transonic speed range. Supercritical airfoils are characterized by their flattened...
January 2024. "Aircraft Research Association". Retrieved 26 January 2024. "Transonic Wind Tunnel Testing". www.ara.co.uk. Aircraft Research Association. Retrieved...
inactive since 2004. Langley retained transonic wind tunnel testing capabilities facilities in the National Transonic Facility, a high pressure, cryogenically...
the other 25% of the way back from the leading edge for subsonic and transonic aircraft. Leading edge sweep is important because the leading edge has...
related devices. With a large enough angle of rearward sweep, in the transonic to low supersonic speed range the wing's leading edge remains behind the...
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