4024 words Hypersonic flight - Wikipedia

Artist's impression of a waverider by the Chinese National Science and Technology Major Project 0901 Flying Vehicle.

Hypersonic flight is flight through the atmosphere below about 90 kilometres at speeds above Mach 5, a speed where dissociation of air begins to become significant and high heat loads exist. Russia is the first country to deploy a hypersonic nuclear missile.

HistoryEdit

The first manufactured object to achieve hypersonic flight was the two-stage Bumper rocket, consisting of a WAC Corporal second stage set on top of a V-2 first stage. In February 1949, at White Sands, the rocket reached a speed of 8288.12 kilometres/h (5150 mph), or approximately Mach 6.7.[1] The vehicle, however, burned on atmospheric re-entry, and only charred remnants were found. In April 1961, Russian Major Yuri Gagarin became the first human to travel at hypersonic speed, during the world's first piloted orbital flight. Soon after, in May 1961, Alan Shepard became the first American and second person to achieve hypersonic flight when his capsule reentered the atmosphere at a speed above Mach 5 at the end of his suborbital flight over the Atlantic Ocean.

In November 1961, Air Force Major Robert White flew the X-15 research airplane at speeds over Mach 6.[2][3] On 2 October 1967, in California, X-15 reached Mach 6.7, but by the time the vehicle approached Edwards Air Force Base, intense heating associated with shock waves around the vehicle had partially melted the pylon that attached the ramjet engine to the fuselage.

The reentry problem of a space vehicle was extensively studied.[4] The NASA X-43A flew on scramjet for 10 seconds, and then glided for 10 minutes on its last flight in 2004. The Boeing X-51 Waverider flew on scramjet for 210 seconds in 2013, finally reaching Mach 5.1 on its fourth flight test. The hypersonic regime has since become the subject for further study during the 20-1th century, and strategic competition between China, Russia, and the U.S.

PhysicsEdit

The stagnation point of air flowing around a body is a point where its local velocity is zero.[4] At this point the air flows around this location. A shock wave forms, which deflects the air from the stagnation point and insulates the flight body from the atmosphere.[4] This can affect the lifting ability of a flight surface to counteract its drag and subsequent free fall.[5] Ning describes a method for interrelating Reynolds number with Mach number.[6]

In order to maneuver in the atmosphere at faster speeds than supersonic, the forms of propulsion can still be airbreathing systems, but a ramjet no longer suffices for a system to attain Mach 5, as a ramjet slows down the airflow to subsonic.[7] Some systems (waveriders) use a first stage rocket to boost a body into the hypersonic regime. Other systems (boost-glide vehicles) use scramjets after their initial boost, in which the speed of the air passing through the scramjet remains supersonic. Other systems (munitions) use a cannon for their initial boost.

High Temperature EffectEdit

Hypersonic flow is a high energy flow.[8] The ratio of kinetic energy to the gas internal energy increases as the square of the Mach number. When this flow enters a boundary layer, there are high viscous effects due to the friction between air and the high-speed object. In this case, the high kinetic energy is converted in part to internal energy and gas energy is proportional to the internal energy. Therefore, hypersonic boundary layers are high temperature regions due to the viscous dissipation of the flow's kinetic energy. Another region of high temperature flow is the shock layer behind the strong bow shock wave. In the case of the shock layer, the flows velocity decreases discontinuously as it passes through the shock wave. This results in a loss of kinetic energy and a gain of internal energy behind the shock wave. Due to high temperatures behind the shock wave, atoms in the air will begin to dissociate. For example, in air when T > 2000 Kelvin, diatomic oxygen will dissociate: O2 → 2O

For T > 4000 Kelvin, diatomic nitrogen will dissociate: N2 → 2N

In this temperature range, nitric oxide will form: N2 + O2 → 2NO, and will ionize: N + O → NO+ + e

Low Density FlowEdit

At standard sea-level condition for air, the mean free path of air molecules is about . Low density air is much thinner. At an altitude of 104 kilometres (342000 feet) the mean free path is . Because of this large free mean path aerodynamic concepts, equations, and results based on the assumption of a continuum begin to break down, therefore aerodynamics must be considered from kinetic theory. This regime of aerodynamics is called low-density flow. For a given aerodynamic condition low-density effects depends on the value of a nondimensional parameter called the Knudsen number , defined as where is the typical length scale of the object considered. The value of the Knudsen number based on nose radius, , can be near one.

Hypersonic vehicles frequently fly at very high altitudes and therefore encounter low-density conditions. Hence, the design and analysis of hypersonic vehicles sometimes require consideration of low-density flow. New generations of hypersonic airplanes may spend a considerable portion of their mission at high altitudes, and for these vehicles, low-density effects will become more significant.[8]

Thin Shock LayerEdit

The flow field between the shock wave and the body surface is called the shock layer. As the Mach number M increases, the angle of the resulting shock wave decreases. This Mach angle is described by the equation where a is the speed of the sound wave and v is the flow velocity. Since M=v/a, the equation becomes . Higher Mach numbers position the shock wave closer to the body surface, thus at hypersonic speeds, the shock wave lies extremely close to the body surface, resulting in a thin shock layer. At low Reynolds number, the boundary layer grows quite thick and merges with the shock wave, leading to a fully viscous shock layer.[9]

Viscous InteractionEdit

The compressible flow boundary layer increases proportionately to the square of the Mach number, and inversely to the square root of the Reynolds number.

At hypersonic speeds, this effect becomes much more pronounced, due to the exponential reliance on the Mach number. Since the boundary layer becomes so large, it interacts more viscously with the surrounding flow. The overall effect of this interaction is to create a much higher skin friction than normal, causing greater surface heat flow. Additionally, the surface pressure spikes, which results in a much larger aerodynamic drag coefficient. This effect is extreme at the leading edge and decreases as a function of length along the surface.[8]

Entropy LayerEdit

The entropy layer is a region of large velocity gradients caused by the strong curvature of the shock wave. The entropy layer begins at the nose of the aircraft and extends downstream close to the body surface. Downstream of the nose, the entropy layer interacts with the boundary layer which causes an increase in aerodynamic heating at the body surface. Although the shock wave at the nose at supersonic speeds is also curved, the entropy layer is only observed at hypersonic speeds because the magnitude of the curve is far greater at hypersonic speeds.[8]

Hypersonic weapons developmentEdit

In the last year, China has tested more hypersonic weapons than we have in a decade. We've got to fix that.

— Michael Griffin, US Undersecretary of Defense for Research and Engineering, Flightglobal (2018)[10]

Hypersonic weapons, by definition, travel five or more times the speed of sound. Hypersonic cruise missiles which are powered by scramjet are restricted below 100000 feet; hypersonic glide vehicles can travel higher. Compared to a ballistic (parabolic) trajectory, a hypersonic vehicle would be capable of large-angle deviations from a parabolic trajectory.[7] According to CNBC, Russia and China lead in hypersonic weapon development, trailed by the United States.[11] France, India, and Australia may also be pursuing the technology.[7]

Waverider hypersonic weapons delivery is an avenue of development. China's XingKong-2 (星空二号, Starry-sky-2), a waverider, had its first flight 3 August 2018.[12][13][14]

In 2016, Russia is believed to have conducted two successful tests of Avangard, a hypersonic glide vehicle. The third known test, in 2017, failed.[15] In 2018, an Avangard was launched at the Dombarovskiy missile base, reaching its target at the Kura shooting range, a distance of 3700 miles.[16] Avangard uses a scramjet engine.[17] Avangard uses new composite materials which are to withstand temperatures of up to 2000 degrees Celsius (3632 degrees Fahrenheit).[18] The Avangard's environment at hypersonic speeds reaches such temperatures.[18] Russia considered its carbon fiber solution to be unreliable,[19] and replaced it with composite materials.[18] Two Avangard hypersonic glide vehicles (HGVs)[20] will first be mounted on SS-19 ICBMs; on 27 December 2019 the weapon was first fielded to the Yasnensky Missile Division, a unit in the Orenburg Oblast.[21] In an earlier report, Franz-Stefan Gady named the unit as the thirteenth Regiment/Dombarovskiy Division (Strategic Missile Force).[20]

These tests have prompted US responses in weapons development[22][23][24] per John Hyten's USSTRATCOM statement 05:03, 8 August 2018 (UTC).[25] At least one vendor is developing ceramics to handle the temperatures of hypersonics systems.[17] There are over a dozen US hypersonics projects as of 2018, notes the commander of USSTRATCOM.[25][26][27] There are also privately developed hypersonic systems.[28]

According to Air Force Chief Scientist, Dr. Greg Zacharias, the US anticipates having hypersonic weapons by the 2020s,[29] hypersonic drones by the 2030s and recoverable hypersonic drone aircraft by the 2040s.[30] The focus of DoD development will be on air-breathing boost-glide hypersonics systems.[31] Countering hypersonic weapons during their cruise phase will require radar with longer range, as well as space-based sensors, and systems for tracking and fire control.[31][32][33][34]

Rand Corporation (28 September 2017) estimates there is less than a decade to prevent Hypersonic Missile proliferation.[35] In the same way that anti-ballistic missiles were developed as countermeasures to ballistic missiles, counter-countermeasures to hypersonics systems were not yet in development, as of 2019.[7][36][19][37] But by 2019, 157.4 million dollars was allocated in the FY2020 Pentagon budget for hypersonic defense, out of 2.6 billion dollars for all hypersonic-related research.[38] Both the US and Russia withdrew from the Intermediate-Range Nuclear Forces (INF) Treaty in February 2019. This will spur arms development, including hypersonic weapons.[39][40]

Flown aircraftEdit

Hypersonic aircraftEdit

SpaceplanesEdit

Cancelled aircraftEdit

Hypersonic aircraftEdit

SpaceplanesEdit

Developing and proposed aircraftEdit

Hypersonic aircraftEdit

Cruise missiles and warheadsEdit

See alsoEdit

ReferencesEdit

  1. ^ Winter, Frank (3 August 2000). "V-2 missile". Smithsonian National Air and Space Museum. airandspace.si.edu. Retrieved 16 August 2018.
  2. ^ White, Robert. "Across the Hypersonic Divide". HistoryNet. HistoryNet LLC. Retrieved 11 October 2015.
  3. ^ "Hypersonic plane passes latest test". ABC News (Australian Broadcasting Corporation). 22 March 2010. Retrieved 18 February 2014.
  4. ^ a b c Alfred J. Eggers, H. Julian Allen, Stanford Neice (10 December 1954), "A comparative analysis of the performance of long-range hypervelocity vehicles", NACA report 1382, pp. 1141–1160
  5. ^ MIT "Fluids" 1. Effects of Reynolds Number 2. Effects of Mach Number
  6. ^ Andrew Ning "Matching Mach and Reynolds Number"
  7. ^ a b c d Amanda Macias (21 March 2018), "Russia and China are 'aggressively developing' hypersonic weapons — here's what they are and why the US can't defend against them: America's top nuclear commander said the U.S. doesn't have defenses against hypersonic weapons. Russia and China are leading the way in developing hypersonic weapons.", CNBC
  8. ^ a b c d Anderson, John (2016). Introduction to Flight (Eighth ed.) McGraw-Hill Education
  9. ^ "Mach Angle". Glenn Research Center, NASA. 6 April 2018.
  10. ^ Garrett Reim (14 December 2018) Counter hypersonic weapon possible by mid-2020s: DoD
  11. ^ Jeff Morganteen, Andrea Miller (SEP 26 2019) Hypersonic weapons are the center of a new arms race between China, the US and Russia
  12. ^ "China tests waverider hypersonic aircraft Starry Sky-2 inches, 3 August 2018
  13. ^ China successfully tests first hypersonic aircraft that can ..
  14. ^ Youtube clip XingKong-2 hypersonic aircraft (Starry Sky-2)
  15. ^ Macias, Amanda (26 December 2018). "The Kremlin says it conducted another successful test of a hypersonic weapon". CNBC. Retrieved 27 December 2018.
  16. ^ "Putin crows as he oversees Russian hypersonic weapons test", ABC News, 26 December 2018
  17. ^ a b Nick Stockton (27 December 2018), "Rotating Detonation Engines Could Propel Hypersonic Flight", Wired
  18. ^ a b c "Putin Says 'Invulnerable' New Hypersonic Nuclear Missile Is Ready For Deployment", The Huffington Post, 27 December 2018
  19. ^ a b Amanda Macias (12 October 2018), "Russia hits a snag in developing a hypersonic weapon after Putin said it was already in production", CNBC
  20. ^ a b Franz-Stefan Gady (November 14, 2019) Russia: Avangard Hypersonic Warhead to Enter Service in Coming Weeks: "The Russian Strategic Missile Force will receive the first two ICBMs fitted with the Avangard warhead in late November or early December." The Avangard HGV was codenamed Yu-71, under Project 4202. “In late November – early December, two UR-100N UTTKh missiles equipped with the hypersonic glide vehicles from the first regiment of Avangard systems will assume experimental combat duty in the Dombarovsky division of the Strategic Missile Force,”—Tass, November 13. The "13th regiment will reportedly be the first unit to receive the two retrofitted SS-19 ICBMs. The regiment is part of the Dombarovskiy (Red Banner) missile division". Eventually 4 more SS-19s fitted with Avangard HGVs will join the thirteenth Regiment; a second regiment with six Avangard / SS-19s will be stood up by 2027.
  21. ^ Vladimir Isachenkov (27 December 2019) "New Russian weapon can travel 27 times the speed of sound", Associated Press. —Avangard has been fielded to the Yasnensky Missile Division, a unit in the Orenburg Oblast"The first regiment with the 'Avangard' took up combat duty" На боевое дежурство заступил первый полк с "Авангардами" (in Russian). Interfax. 27 December 2019.
  22. ^ a b Lockheed Martin Hypersonic Conventional Strike Weapon (HCSW) Missile for US Air Force
  23. ^ Joseph Trevithick (6 September 2018), "DARPA Starts Work On 'Glide Breaker' Hypersonic Weapons Defense Project", The Drive
  24. ^ "Lockheed Martin gets a second hypersonic weapons contract, this time for 480 million dollars , as the US tries to keep pace with Russia and China", 14 August 2018, CNBC
  25. ^ a b USSTRATCOM, CNBC
  26. ^ Sydney Freedberg (13 March 2019), "Hypersonics Won't Repeat Mistakes Of F-35 inches, Breaking Defense
  27. ^ Joseph Trevithic (6 August 2019), "Air Force Reveals Tests Of Supposed Record-Setting Scramjet Engine From Northrop Grumman"
  28. ^ Colin Clark (19 June 2019), "Raytheon, Northrop Will 'Soon' Fly Hypersonic Cruise Missile", Breaking Defense, Paris Air Show, new additive-process materials to build the combustor of a scramjet; potential integration among members of an intercommunicating swarm of hypersonics systems.
  29. ^ Sean Kimmons (31 May 2019), "Joint hypersonic weapon tests to start next year", Army News Service
  30. ^ Osborn, Kris. "Get Ready, Russia and China: America's Next Fighter Jet Will Dominate the Skies". The National Interest. Retrieved 2 March 2018.
  31. ^ a b David Vergun (December 14, 2018), "DOD scaling up effort to develop hypersonics", U.S. Army
  32. ^ Loren Thompson (30 July 2019) "Defense Against Hypersonic Attack Is Becoming The Biggest Military Challenge Of The Trump Era"
  33. ^ John L. Dolan, Richard K. Gallagher & David L. Mann (23 April 2019) "Hypersonic Weapons – A Threat to National Security" Hypersonic and Ballistic Tracking Space Sensor (HBTSS)
  34. ^ Paul McLeary (18 December 2019), "MDA Kickstarts New Way To Kill Hypersonic Missiles" MDA's Hypersonic Defense Weapon System - 4 Interceptors
  35. ^ "Hypersonic Missile Nonproliferation", Rand Corporation, 28 September 2017, via YouTube
  36. ^ a b "Putin unveils new nuclear missile, says 'listen to us now'". nbcnews.com. Retrieved 2 March 2018.
  37. ^ Sydney Freedberg (1 February 2019) "Pentagon Studies Post-INF Weapons, Shooting Down Hypersonics", Breaking Defense
  38. ^ a b c d Kelley M. Sayler (11 July 2019), "Hypersonic Weapons: Background and Issues for Congress", Congressional Research Service
  39. ^ Linda Givetash (2 February 2019), "Putin says Russia also suspending key nuclear arms treaty after U.S. move to withdraw", NBC News, Reuters
  40. ^ Rebecca Kheel and Morgan Chalfant (31 July 2019) "Landmark US-Russia arms control treaty poised for final blow", The Hill
  41. ^ China unveils Dongfeng-17 conventional missiles in military parade, 1 October 2019, via YouTube. See minute 0:05 to 0:49 for 16 Hypersonic Glide Vehicles (white-tipped contrast atop their DF-17 fuselages mounted on booster rockets.
  42. ^ Ankit Panda (October 7, 2019) "Hypersonic Hype: Just How Big of a Deal Is China's DF-17 Missile?", The Diplomat. A conventional-weapons-only boost-glide HGV mounted on endo-atmospheric fuselage (DF-17).
  43. ^ "DRDO conducts maiden test of hypersonic technology demonstrator". The Hindu.
  44. ^ Mark Wade. "Tsien Spaceplane 1949 inches. astronautix.com.
  45. ^ "Valier "Raketenschiff" (1929): Classic Rocketship Series #6 inches. The Virtual Museum of Flying Wonders. Fantastic Plastic Models.
  46. ^ "Rockwell C-1057 "Breadbox" Space Shuttle (1972)". The Virtual Museum of Flying Wonders. Fantastic Plastic Models.
  47. ^ Cui, et. al. (February 2019) Hypersonic I-shaped aerodynamic configurations Science China Physics, Mechanics & Astronomy 61:024722 Wind tunnel proposal
  48. ^ "Boeing Unveils Hypersonic Airliner Concept". Aviation Week. 26 June 2018.
  49. ^ Joe Pappalardo (26 June 2018). "How Boeing's Hypersonic Passenger Plane Concept Works". Popular Mechanics.
  50. ^ Dan Goure (20 June 2019) "Hypersonic Weapons Are Almost Here (And They Will Change War Forever)" Lockheed-Martin vs Raytheon-Northrup
  51. ^ Steve Trimble (29 July 2019), "Raytheon Tactical Boost Glide Baseline Review Completed", Aviation Week
  52. ^ Dr. Peter Erbland, Lt. Col. Joshua Stults () "Tactical Boost Glide"
  53. ^ D. Preller; P. M. Smart. "Abstract: SPARTAN: Scramjet Powered Accelerator for Reusable Technology AdvaNcement" (PDF). 2014 ReinventingSpace Conference (Rispace 2014).
  54. ^ "High-Speed Experimental Fly Vehicles - INTernational". European Space Agency.
  55. ^ a b c Allen Cone ( JUNE 14, 2019) Air Force tests hypersonic weapon aboard B-52 for first time
  56. ^ Chris Martin (17 December 2019) "Lockheed awards $81.5M contract for hypersonic missile motor", Defense News, HCSW $81.5M, ARRW
  57. ^ Joseph Trevithick (18 June 2019), "Northrop And Raytheon Have Been Secretly Working On Scramjet Powered Hypersonic Missile", The Drive
  58. ^ a b Kris Osborn (1 October 2019), :Air Force arms B1-B bomber with hypersonic weapons", Fox News
  59. ^ Kyle Mizokami (18 September 2019) "The Air Force Is Working on 'Hacksaw,' a Mach 5 Missile", Popular Mechanics

External linksEdit

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