transonic

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(また transsonic)音速に近い,音速前後の

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/07/21 13:48:17」(JST)

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Aerodynamic condensation evidences shockwaves around a transonic F/A-18

The 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 wings

Transonic flow patterns on an airfoil showing flow patterns at and above critical Mach number

In aeronautics, transonic refers to the condition of flight in which a range of velocities of airflow exist surrounding and flowing past an air vehicle or an airfoil that are concurrently below, at, and above the speed of sound in the range of Mach 0.8 to 1.0, i.e. 600–768 mph (965–1236 km/h) at sea level. This condition depends not only on the travel speed of the craft, but also on the temperature of the airflow in the vehicle's local environment. It is formally defined as the range of speeds between the critical Mach number, when some parts of the airflow over an air vehicle or airfoil are supersonic, and a higher speed, typically near Mach 1.2, when the vast majority of the airflow is supersonic. Between these speeds some of the airflow is supersonic, but a significant fraction is not.

Most modern jet powered aircraft are engineered to operate at transonic air speeds. Transonic airspeeds see a rapid increase of 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.

Severe instability can occur at transonic speeds. Shock waves move through the air at the speed of sound. When an object such as an aircraft also moves at the speed of sound, these shock waves build up in front of it to form a single, very large shock wave. During transonic flight, the plane must pass through this large shock wave, as well as contend with the instability caused by air moving faster than sound over parts of the wing and slower in other parts.

Transonic speeds can also occur at the tips of rotor blades of helicopters and aircraft. However, as this puts severe, unequal stresses on the rotor blade, it is avoided and may lead to dangerous accidents if it occurs. It is one of the limiting factors to the size of rotors, and also to the forward speeds of helicopters (as this speed is added to the forward-sweeping (leading) side of the rotor, thus possibly causing localized transonics).

Condensation clouds

At transonic speeds intense low-pressure areas form at various points around an aircraft. If conditions are right (i.e. high humidity) visible clouds will form in these low-pressure areas as shown in the illustration; these are called Prandtl-Glauert singularities. These clouds remain with the aircraft as it travels. It is not necessary for the aircraft as a whole to reach supersonic speeds for these clouds to form. It is also a buildup of shock waves.

Transonic flows in astronomy and astrophysics

In astrophysics, wherever there is evidence of shocks (standing, propagating or oscillating), the flow close by must be transonic, as only supersonic flows form shocks. Interestingly, all black hole accretions are transonic.^[1] Many such flows also have shocks very close to the black holes.

The outflows or jets from young stellar objects or disks around black holes can also be transonic since they start subsonically and at a far distance they are invariably supersonic. Supernovae explosions are accompanied by supersonic flows and shock waves. Bow shocks formed in solar winds are a direct result of transonic winds from a star. It has been long thought that a bow shock was present around the heliosphere of our solar system. This was recently found not to be the case according to IBEX data.^[2]

References

^ Chakrabarti, Sandip (1990). Theory of Transonic Astrophysical Flows. Singapore: World Scientific. ISBN 981-02-0204-0.
^ "NASA – IBEX Reveals a Missing Boundary At the Edge of the Solar System", Science daily, 2012-05-10 .

English Journal

Protective Effect of Nitric Oxide on Liver Circulation from Ischemia Reperfusion Injury.

Toshihiro W1, Kurata S1, Takuro S1, Ichiro O1, Yasuaki S2, Ikeda T2, Ureshino H3, Ayuse T1.
Journal of investigative surgery : the official journal of the Academy of Surgical Research.J Invest Surg.2015 Oct;28(5):236-44. doi: 10.3109/08941939.2015.1024357. Epub 2015 Aug 20.
INTRODUCTION: The reduction of endogenous nitric oxide (NO) production during hepatic ischemia-reperfusion injury, generally via a reduction in endothelial NO synthase activity, leads to liver injury. We hypothesized that administration of an exogenous NO donor into the portal vein may ameliorate he
PMID 26290958

Anticancer effects of crude extract from Melia toosendan Sieb. et Zucc on hepatocellular carcinoma in vitro and in vivo.

Liu XL1, Wang H1, Zhang L1, Wang YL2, Wang J1, Wang P1, He X1, He YJ3.
Chinese journal of integrative medicine.Chin J Integr Med.2015 Sep 17. [Epub ahead of print]
OBJECTIVE: To investigate the anti-cancer effects of crude extract from Melia toosendan Sieb. et Zucc and its possible molecular mechanisms in vitro and in vivo.METHODS: Transonic alcohol-chloroform extraction method was used to extract toosendanin from the bark of Melia toosendan Sieb. et Zucc, and
PMID 26383159

Free boundary problems in shock reflection/diffraction and related transonic flow problems.

Chen GQ1, Feldman M2.
Philosophical transactions. Series A, Mathematical, physical, and engineering sciences.Philos Trans A Math Phys Eng Sci.2015 Sep 13;373(2050). pii: 20140276. doi: 10.1098/rsta.2014.0276.
Shock waves are steep wavefronts that are fundamental in nature, especially in high-speed fluid flows. When a shock hits an obstacle, or a flying body meets a shock, shock reflection/diffraction phenomena occur. In this paper, we show how several long-standing shock reflection/diffraction problems c
PMID 26261363

Japanese Journal

Numerical Simulation of Shock-Stall Flutter of a High-Aspect-Ratio Forward-Swept Wing

ISOGAI Koji
Transactions of the Japan Society for Aeronautical and Space Sciences 56(5), 303-311, 2013-09
NAID 40019765932

Active Aeroelastic Control using Multiple Control Surfaces Based on a High-Fidelity Reduced Order Model

CHEN Gang,WANG Xian,LI Yueming
Transactions of the Japan Society for Aeronautical and Space Sciences 56(5), 261-268, 2013-09
NAID 40019765874

ロケットフェアリング遷音速流れにおける微小突起の影響

堤誠司,高木亮治,高間良樹 [他]
日本航空宇宙学会論文集 = Journal of the Japan Society for Aeronautical and Space Sciences 61(4), 103-109, 2013-08
NAID 40019779796

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