Aerodynamics is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dynamics and its subfield of gas dynamics, and is an important domain of study in aeronautics. The term aerodynamics is often used synonymously with gas dynamics, the difference being that "gas dynamics" applies to the study of the motion of all gases, and is not limited to air. The formal study of aerodynamics began in the modern sense in the eighteenth century, although observations of fundamental concepts such as aerodynamic drag were recorded much earlier. Most of the early efforts in aerodynamics were directed toward achieving heavier-than-air flight, which was first demonstrated by Otto Lilienthal in 1891. Since then, the use of aerodynamics through mathematical analysis, empirical approximations, wind tunnel experimentation, and computer simulations has formed a rational basis for the development of heavier-than-air flight and a number of other technologies. Recent work in aerodynamics has focused on issues related to compressible flow, turbulence, and boundary layers and has become increasingly computational in nature.
In aerodynamics, a hypersonic speed is one that exceeds five times the speed of sound, often stated as starting at speeds of Mach 5 and above.
In aeronautics, the aspect ratio of a wing is the ratio of its span to its mean chord. It is equal to the square of the wingspan divided by the wing area. Thus, a long, narrow wing has a high aspect ratio, whereas a short, wide wing has a low aspect ratio.
In aeronautics, downwash is the change in direction of air deflected by the aerodynamic action of an airfoil, wing, or helicopter rotor blade in motion, as part of the process of producing lift. In helicopter aerodynamics discussions, it may be referred to as induced flow.
The Arnold Engineering Development Complex (AEDC), Arnold Engineering Development Center before July 2012, is an Air Force Materiel Command facility under the control of the Air Force Test Center (AFTC). Named for General Henry "Hap" Arnold, the father of the U.S. Air Force, AEDC is the most advanced and largest complex of flight simulation test facilities in the world.
In fluid mechanics, an aerodynamic force is a force exerted on a body by the air in which the body is immersed, and is due to the relative motion between the body and the gas.
Gas kinetics is a science in the branch of fluid dynamics, concerned with the study of motion of gases and its effects on physical systems. Based on the principles of fluid mechanics and thermodynamics, gas dynamics arises from the studies of gas flows in transonic and supersonic flights. To distinguish itself from other sciences in fluid dynamics, the studies in gas dynamics are often defined with gases flowing around or within physical objects at speeds comparable to or exceeding the speed of sound and causing a significant change in temperature and pressure. Some examples of these studies include but are not limited to: choked flows in nozzles and valves, shock waves around jets, aerodynamic heating on atmospheric reentry vehicles and flows of gas fuel within a jet engine. At the molecular level, gas dynamics is a study of the kinetic theory of gases, often leading to the study of gas diffusion, statistical mechanics, chemical thermodynamics and non-equilibrium thermodynamics. Gas dynamics is synonymous with aerodynamics when the gas field is air and the subject of study is flight. It is highly relevant in the design of aircraft and spacecraft and their respective propulsion systems.
The A. James Clark School of Engineering is the engineering college of the University of Maryland, College Park. The school consists of fourteen buildings on the College Park campus that cover over 750,000 sq ft (70,000 m2). The school is near Washington, D.C. and Baltimore, as well as several technology-driven institutions.
The Ayaks is a hypersonic waverider aircraft program started in the Soviet Union and currently under development by the Hypersonic Systems Research Institute (HSRI) of Leninets Holding Company in Saint Petersburg, Russia.
Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is similar, but deals with the electronics side of aerospace engineering.
Hans G. Hornung is an emeritus C. L. "Kelly" Johnson Professor of Aeronautics and Director of the Guggenheim Aeronautical Laboratory of the California Institute of Technology (GALCIT). He received his bachelor (1960) and master (1962) degrees from the University of Melbourne and his Ph.D. degree (1965) in Aeronautics from Imperial College, London. He worked in the Aeronautical Research Laboratories, Melbourne, and in the Physics Department of the Australian National University (1967–1980), with a sabbatical year as a Humboldt Fellow in Darmstadt, Germany, 1974. In 1980 he accepted an offer to head the Institute for Experimental Fluid Mechanics of the DLR in Göttingen, Germany. He left Germany in 1987 to serve as the director of GALCIT. During his time at GALCIT he oversaw the construction of three large facilities: the T5 hypervelocity shock tunnel, the John Lucas Adaptive-Wall Wind Tunnel, and a supersonic Ludwieg tube.
The Aeronautical/Astronautical Research Laboratory (AARL) is an aerospace engineering research facility operated by Ohio State University. It is the principal research facility of the College of Engineering's Department of Aerospace and Astronautical Engineering. It is located on the grounds of Ohio State University Airport, in Columbus, Ohio.
The Purdue University School of Aeronautics and Astronautics is Purdue University's school of aerospace engineering contained within the Purdue University College of Engineering. The school offers B.S., M.S., and Ph.D. degrees in aeronautical and astronautical engineering. It also provides distance graduate education, including an online M.S. in Engineering with concentration in Aeronautics and Astronautics, and a distance Ph.D. Its main office and some of its labs are located in the Neil Armstrong Hall of Engineering. As of 2010, the School has awarded an estimated 6% of BS degrees and 7% of PhDs in aerospace engineering in the United States.
Ulfila Mark J. Lewis is a senior American aerospace and defense executive with special expertise in hypersonics. He is currently the Executive Director of the National Defense Industrial Association's Emerging Technologies Institute, following his role in the second half of 2020 as the acting US Deputy Under Secretary of Defense for Research and Engineering, and before that the Director of Defense Research and Engineering for Modernization. He was the Chief Scientist of the U.S. Air Force, Washington, D.C. from 2004 to 2008 and was the longest-serving Chief Scientist in Air Force history. He served as chief scientific adviser to the Chief of Staff and Secretary of the Air Force, and provided assessments on a wide range of scientific and technical issues affecting the Air Force mission. In this role he identified and analyzed technical issues and brought them to attention of Air Force leaders, and interacted with other Air Staff principals, operational commanders, combatant commands, acquisition, and science & technology communities to address cross-organizational technical issues and solutions. His primary areas of focus included energy, sustainment, long-range strike technologies, advanced propulsion systems, and workforce development.
Aerodynamics is a branch of dynamics concerned with the study of the motion of air. It is a sub-field of fluid and gas dynamics, and the term "aerodynamics" is often used when referring to fluid dynamics
Prof. Alfred Gessow was an American pioneer in the field of helicopter aerodynamics and aerospace engineering. He was a co-author of the early rotorcraft engineering text Aerodynamics of the Helicopter, which, although published in 1952, has been in print for more than 50 years. Gessow was chair of the Department of Aerospace Engineering at the University of Maryland, College Park, and was ultimately promoted to Professor Emeritus.
This glossary of aerospace engineering terms pertains specifically to aerospace engineering, its sub-disciplines, and related fields including aviation and aeronautics. For a broad overview of engineering, see glossary of engineering.
Guru Guruswamy is an American engineer working as Principal Scientist at Ames Research Center since 1988. He pioneered research in the area of computational aeroelasticity that involves Unsteady Aerodynamics, Finite Element Methods, Computational Fluid Dynamics, Parallel Computing and Problem-Solving Environment. His innovative research was utilized in the first commercial 3-D computational aeroelasticity software developed by a major aerospace industry. The aeroelasticity legend Holt Ashley extensively referred to Guruswamy's research in his classical review paper. In 1988 he demonstrated the unique use of Transonic Small Perturbation based CFD for designing active controls to increase the safety of aircraft. It was followed by a break through development of Euler flow equations based Computational Aeroelasticy. It was cited by another Aeroelasticity legend John Dugundji of MIT as an important milestone in Aeroelasticity. A google search shows about 150 researchers took advantage Guruswamy's work based on the Euler equations for follow-up developments.
Isaac Newton's sine-squared law of air resistance is a formula that implies the force on a flat plate immersed in a moving fluid is proportional to the square of the sine of the angle of attack. Although Newton did not analyze the force on a flat plate himself, the techniques he used for spheres, cylinders, and conical bodies were later applied to a flat plate to arrive at this formula. In 1687, Newton devoted the second volume of his Principia Mathematica to fluid mechanics.
The Fay-Riddell equation is a fundamental relation in the fields of aerospace engineering and hypersonic flow, which provides a method to estimate the stagnation point heat transfer rate on a blunt body moving at hypersonic speeds in dissociated air. The heat flux for a spherical nose is computed according to quantities at the wall and the edge of an equilibrium boundary layer.
