Chapter 3 Lecture 10 Drag Polar
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Aerodynamics Material - Taylor & Francis
CopyrightAerodynamics material - Taylor & Francis ______________________________________________________________________ 257 Aerodynamics Symbol List Symbol Definition Units a speed of sound ⁄ a speed of sound at sea level ⁄ A area aspect ratio ‐‐‐‐‐‐‐‐ b wing span c chord length c Copyrightmean aerodynamic material chord- Taylor & Francis specific heat at constant pressure of air · root chord tip chord specific heat at constant volume of air · / quarter chord total drag coefficient ‐‐‐‐‐‐‐‐ , induced drag coefficient ‐‐‐‐‐‐‐‐ , parasite drag coefficient ‐‐‐‐‐‐‐‐ , wave drag coefficient ‐‐‐‐‐‐‐‐ local skin friction coefficient ‐‐‐‐‐‐‐‐ lift coefficient ‐‐‐‐‐‐‐‐ , compressible lift coefficient ‐‐‐‐‐‐‐‐ compressible moment ‐‐‐‐‐‐‐‐ , coefficient , pitching moment coefficient ‐‐‐‐‐‐‐‐ , rolling moment coefficient ‐‐‐‐‐‐‐‐ , yawing moment coefficient ‐‐‐‐‐‐‐‐ ______________________________________________________________________ 258 Aerodynamics Aerodynamics Symbol List (cont.) Symbol Definition Units pressure coefficient ‐‐‐‐‐‐‐‐ compressible pressure ‐‐‐‐‐‐‐‐ , coefficient , critical pressure coefficient ‐‐‐‐‐‐‐‐ , supersonic pressure coefficient ‐‐‐‐‐‐‐‐ D total drag induced drag Copyright material - Taylor & Francis parasite drag e span efficiency factor ‐‐‐‐‐‐‐‐ L lift pitching moment · rolling moment · yawing moment · M mach number ‐‐‐‐‐‐‐‐ critical mach number ‐‐‐‐‐‐‐‐ free stream mach number ‐‐‐‐‐‐‐‐ P static pressure ⁄ total pressure ⁄ free stream pressure ⁄ q dynamic pressure ⁄ R -
Concorde Is a Museum Piece, but the Allure of Speed Could Spell Success
CIVIL SUPERSONIC Concorde is a museum piece, but the allure Aerion continues to be the most enduring player, of speed could spell success for one or more and the company’s AS2 design now has three of these projects. engines (originally two), the involvement of Air- bus and an agreement (loose and non-exclusive, by Nigel Moll but signed) with GE Aviation to explore the supply Fourteen years have passed since British Airways of those engines. Spike Aerospace expects to fly a and Air France retired their 13 Concordes, and for subsonic scale model of the design for the S-512 the first time in the history of human flight, air trav- Mach 1.5 business jet this summer, to explore low- elers have had to settle for flying more slowly than speed handling, followed by a manned two-thirds- they used to. But now, more so than at any time scale supersonic demonstrator “one-and-a-half to since Concorde’s thunderous Olympus afterburn- two years from now.” Boom Technology is working ing turbojets fell silent, there are multiple indi- on a 55-seat Mach 2.2 airliner that it plans also to cations of a supersonic revival, and the activity offer as a private SSBJ. NASA and Lockheed Martin appears to be more advanced in the field of busi- are encouraged by their research into reducing the ness jets than in the airliner sector. severity of sonic booms on the surface of the planet. www.ainonline.com © 2017 AIN Publications. All Rights Reserved. For Reprints go to Shaping the boom create what is called an N-wave sonic boom: if The sonic boom produced by a supersonic air- you plot the pressure distribution that you mea- craft has long shaped regulations that prohibit sure on the ground, it looks like the letter N. -
NASA Supercritical Airfoils
NASA Technical Paper 2969 1990 NASA Supercritical Airfoils A Matrix of Family-Related Airfoils Charles D. Harris Langley Research Center Hampton, Virginia National Aeronautics-and Space Administration Office of Management Scientific and Technical Information Division Summary wind-tunnel testing. The process consisted of eval- A concerted effort within the National Aero- uating experimental pressure distributions at design and off-design conditions and physically altering the nautics and Space Administration (NASA) during airfoil profiles to yield the best drag characteristics the 1960's and 1970's was directed toward develop- over a range of experimental test conditions. ing practical two-dimensional turbulent airfoils with The insight gained and the design guidelines that good transonic behavior while retaining acceptable were recognized during these early phase 1 investiga- low-speed characteristics and focused on a concept tions, together with transonic, viscous, airfoil anal- referred to as the supercritical airfoil. This dis- ysis codes developed during the same time period, tinctive airfoil shape, based on the concept of local resulted in the design of a matrix of family-related supersonic flow with isentropic recompression, was supercritical airfoils (denoted by the SC(phase 2) characterized by a large leading-edge radius, reduced prefix). curvature over the middle region of the upper surface, and substantial aft camber. The purpose of this report is to summarize the This report summarizes the supercritical airfoil background of the NASA supercritical airfoil devel- development program in a chronological fashion, dis- opment, to discuss some of the airfoil design guide- lines, and to present coordinates of a matrix of cusses some of the design guidelines, and presents family-related supercritical airfoils with thicknesses coordinates of a matrix of family-related super- critical airfoils with thicknesses from 2 to 18 percent from 2 to 18 percent and design lift coefficients from and design lift coefficients from 0 to 1.0. -
Experimental and Numerical Investigations of a 2D Aeroelastic Arifoil Encountering a Gust in Transonic Conditions Fabien Huvelin, Arnaud Lepage, Sylvie Dequand
Experimental and numerical investigations of a 2D aeroelastic arifoil encountering a gust in transonic conditions Fabien Huvelin, Arnaud Lepage, Sylvie Dequand To cite this version: Fabien Huvelin, Arnaud Lepage, Sylvie Dequand. Experimental and numerical investigations of a 2D aeroelastic arifoil encountering a gust in transonic conditions. CEAS Aeronautical Journal, Springer, In press, 10.1007/s13272-018-00358-x. hal-02027968 HAL Id: hal-02027968 https://hal.archives-ouvertes.fr/hal-02027968 Submitted on 22 Feb 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. 1 EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF A 2D 2 AEROELASTIC AIRFOIL ENCOUNTERING A GUST IN TRANSONIC 3 CONDITIONS 4 Fabien HUVELIN1, Arnaud LEPAGE, Sylvie DEQUAND 5 6 ONERA-The French Aerospace Lab 7 Aerodynamics, Aeroelasticity, Acoustics Department 8 Châtillon, 92320 FRANCE 9 10 KEYWORDS: Aeroelasticity, Wind Tunnel Test, CFD, Gust response, Unsteady coupled 11 simulations 12 ABSTRACT: 13 In order to make substantial progress in reducing the environmental impact of aircraft, a key 14 technology is the reduction of aircraft weight. This challenge requires the development and 15 the assessment of new technologies and methodologies of load prediction and control. To 16 achieve the investigation of the specific case of gust load, ONERA defined a dedicated 17 research program based on both wind tunnel test campaigns and high fidelity simulations. -
The Supercritical Airfoil
TF-2004-13 DFRC The Supercritical Airfoil Supercritical wings add a graceful appearance to the modified NASA F-8 test aircraft. NASA Photo E73-3468 An airfoil considered unconventional when tested in the early 1970s by NASA at the Dryden Flight Research Center is now universally recognized by the aviation industry as a wing design that increases flying efficiency and helps lower fuel costs. Called the supercritical airfoil, the design has led to development of the supercritical wings (SCW) now used worldwide on business jets, airliners and transports, and numerous military aircraft. Conventional wings are rounded on top and flat on the bottom. The SCW is flatter on the top, rounded on the bottom, and the upper trailing edge is accented with a downward curve to restore lift lost by flattening the upper surface. 1 At speeds in the transonic range -- just below vibrations. In rare cases, aircraft have also become and just above the speed of sound -- the SCW delays uncontrollable due to boundary layer separation. the formation of the supersonic shock wave on the upper wing surface and reduces its strength, allowing Supercritical wings have a flat-on-top "upside the aircraft to fly faster with less effort. down" look. As air moves across the top of a SCW it does not speed up nearly as much as over a curved NASA's test program validating the SCW upper surface. This delays the onset of the shock concept was conducted at the Dryden Flight wave and also reduces aerodynamic drag associated Research Center from March 1971 to May 1973 and with boundary layer separation. -
Drag Bookkeeping
Drag Drag Bookkeeping Drag may be divided into components in several ways: To highlight the change in drag with lift: Drag = Zero-Lift Drag + Lift-Dependent Drag + Compressibility Drag To emphasize the physical origins of the drag components: Drag = Skin Friction Drag + Viscous Pressure Drag + Inviscid (Vortex) Drag + Wave Drag The latter decomposition is stressed in these notes. There is sometimes some confusion in the terminology since several effects contribute to each of these terms. The definitions used here are as follows: Compressibility drag is the increment in drag associated with increases in Mach number from some reference condition. Generally, the reference condition is taken to be M = 0.5 since the effects of compressibility are known to be small here at typical conditions. Thus, compressibility drag contains a component at zero-lift and a lift-dependent component but includes only the increments due to Mach number (CL and Re are assumed to be constant.) Zero-lift drag is the drag at M=0.5 and CL = 0. It consists of several components, discussed on the following pages. These include viscous skin friction, vortex drag due to twist, added drag due to fuselage upsweep, control surface gaps, nacelle base drag, and miscellaneous items. The Lift-Dependent drag, sometimes called induced drag, includes the usual lift- dependent vortex drag together with lift-dependent components of skin friction and pressure drag. For the second method: Skin Friction drag arises from the shearing stresses at the surface of a body due to viscosity. It accounts for most of the drag of a transport aircraft in cruise. -
Postal Penguin an Unmanned Combat Air Vehicle for the Navy
Postal Penguin An Unmanned Combat Air Vehicle for the Navy Team 8-Ball Final Presentation April 22nd, 2003 1 Agenda Introduction Background Research Concept Overview, Selection Design Evolution, Weights Final Configuration Systems Overview Aero-Performance Control & Stability Structural Analysis Pelikan Tail Autonomy, Carrier Integration Cost Summary and Questions 2 Introduction Team Members and Positions Justin Hayes Greg Little Ben Smith David Andrews Chuhui Pak Alex Rich Nate Wright Jon Hirschauer Christina DeLorenzo 3 Introduction Request for Proposal Overview RFP Requirement Specification Effect of Specification Mission 1, Strike Range 500 nm High Fuel Requirements Mission 2, Endurance 10 Hrs Low TSFC, High Fuel Payload 4,600 lbs Internal Volume Cruise Speed > M 0.7 No Supersonic, Engine Ceiling > 40,000 ft Engine, Aero Performance Sensor Suite Global Hawk Volume, Integration Stealth Survivability Oblique Angles Carrier Ops Structural Loads 4 Introduction Project Drivers (Pictures Courtesy of Global Security) Carrier Operation Fuel Store Capacity Stealth Sensor Suite Flyaway Costs 5 Agenda Introduction Background Research Concept Overview, Selection Design Evolution, Weights Final Configuration Systems Overview Aero-Performance Control & Stability Structural Analysis Pelikan Tail Autonomy, Carrier Integration Cost Summary and Questions 6 Background Research Existing Aircraft (Pictures Courtesy of GlobalSecurity) 7 Background Research Advanced Technologies, VSTOL Harrier Review 14 Panel Study AV-8b Harrier -
Fluid Mechanics, Drag Reduction and Advanced Configuration Aeronautics
NASA/TM-2000-210646 Fluid Mechanics, Drag Reduction and Advanced Configuration Aeronautics Dennis M. Bushnell Langley Research Center, Hampton, Virginia December 2000 The NASA STI Program Office ... in Profile Since its founding, NASA has been dedicated to CONFERENCE PUBLICATION. Collected the advancement of aeronautics and space papers from scientific and technical science. The NASA Scientific and Technical conferences, symposia, seminars, or other Information (STI) Program Office plays a key meetings sponsored or co-sponsored by part in helping NASA maintain this important NASA. role. SPECIAL PUBLICATION. Scientific, The NASA STI Program Office is operated by technical, or historical information from Langley Research Center, the lead center for NASA programs, projects, and missions, NASA's scientific and technical information. The often concerned with subjects having NASA STI Program Office provides access to the substantial public interest. NASA STI Database, the largest collection of aeronautical and space science STI in the world. TECHNICAL TRANSLATION. English- The Program Office is also NASA's institutional language translations of foreign scientific mechanism for disseminating the results of its and technical material pertinent to NASA's research and development activities. These mission. results are published by NASA in the NASA STI Report Series, which includes the following Specialized services that complement the STI report types: Program Office's diverse offerings include creating custom thesauri, building customized TECHNICAL PUBLICATION. Reports of databases, organizing and publishing research completed research or a major significant results ... even providing videos. phase of research that present the results of NASA programs and include extensive For more information about the NASA STI data or theoretical analysis. -
2. Afterburners
2. AFTERBURNERS 2.1 Introduction The simple gas turbine cycle can be designed to have good performance characteristics at a particular operating or design point. However, a particu lar engine does not have the capability of producing a good performance for large ranges of thrust, an inflexibility that can lead to problems when the flight program for a particular vehicle is considered. For example, many airplanes require a larger thrust during takeoff and acceleration than they do at a cruise condition. Thus, if the engine is sized for takeoff and has its design point at this condition, the engine will be too large at cruise. The vehicle performance will be penalized at cruise for the poor off-design point operation of the engine components and for the larger weight of the engine. Similar problems arise when supersonic cruise vehicles are considered. The afterburning gas turbine cycle was an early attempt to avoid some of these problems. Afterburners or augmentation devices were first added to aircraft gas turbine engines to increase their thrust during takeoff or brief periods of acceleration and supersonic flight. The devices make use of the fact that, in a gas turbine engine, the maximum gas temperature at the turbine inlet is limited by structural considerations to values less than half the adiabatic flame temperature at the stoichiometric fuel-air ratio. As a result, the gas leaving the turbine contains most of its original concentration of oxygen. This oxygen can be burned with additional fuel in a secondary combustion chamber located downstream of the turbine where temperature constraints are relaxed. -
In-Flight Camber Transformation of Aircraft Wing Based on Variation in Thickness-To-Chord Ratio
International Journal of Industrial Electronics and Electrical Engineering, ISSN: 2347-6982 Volume-2, Issue-7, July-2014 IN-FLIGHT CAMBER TRANSFORMATION OF AIRCRAFT WING BASED ON VARIATION IN THICKNESS-TO-CHORD RATIO 1PRITAM KUMAR PRATIHARI, 2NAVUDAY SHARMA, 3JAYRAJINAMDAR 1,2,3Amity Institute of Space Science and Technology, Amity University, Noida, 201303, Uttar Pradesh, India. E-mail: [email protected], [email protected], [email protected] Abstract- In general, there is wide gap between subsonic flight and supersonic flight, mainly due to aerodynamic limitations. This paper presents a method for development of next generation aircraft wings whose camber can be transformed in-flight for enabling it to fly efficiently in different regimes of Mach number; say, Subsonic to supersonic and vice-versa. To demonstrate the aerodynamic performance of the subsonic airfoil (C141A) and a supersonic airfoil (NACA 65206), the flow is simulated by using the commercial program GAMBIT and FLUENT. An important aspect is the mechanical and hydraulic transformation mechanism working inside the wing which helps it to change the camber according to the requirement. For this mechanism, a Hydraulic expansion-contraction system is used which works on the principle of Master and Slave Piston-cylinder arrangement. This concept can be practically very important to increase aerodynamic efficiency of the aircraft in different regions of subsonic, transonic and supersonic flights. Moreover, this idea of real-time camber transformation can make an aircraft multipurpose in accordance to Mach regime of flight. I. INTRODUCTION transform the camber of the subsonic airfoil to supersonic airfoil and vice versa in flight by variation Much research on the development of aircraft wings of thickness to chord ratio of the airfoil. -
For the Full Potential Equation of Transonic Flow*
MATHEMATICS OF COMPUTATION VOLUME 44, NUMBER 169 JANUARY 1985, PAGES 1-29 Entropy Condition Satisfying Approximations for the Full Potential Equation of Transonic Flow* By Stanley Osher, Mohamed Hafez and Woodrow Whitlow, Jr. Abstract. We shall present a new class of conservative difference approximations for the steady full potential equation. They are, in general, easier to program than the usual density biasing algorithms, and in fact, differ only slightly from them. We prove rigorously that these new schemes satisfy a new discrete "entropy inequality", which rules out expansion shocks, and that they have sharp, steady, discrete shocks. A key tool in our analysis is the construction of an "entropy inequality" for the full potential equation itself. We conclude by presenting results of some numerical experiments using our new schemes. I. Introduction. The full potential equation is a common model for describing supersonic and subsonic flow close to the speed of sound. The flow is assumed to be that of a perfect gas, and the assumptions of irrotationality and constant entropy are made. The resulting equation is a single nonlinear partial differential equation of second order, which changes type from hyperbolic to elliptic, as the flow goes from supersonic to subsonic. Flows with a supersonic component generally have solutions with shocks, so the conservation form of the equation is important. This formulation, (FP), is one of three conservative formulations used for inviscid transonic flows. The other two are transonic small-disturbance equation, (TSD), and Euler equation, (EU), which is the exact inviscid formulation. The FP formulation is the most efficient of the three in terms of accuracy-to-cost ratio for a wide range of inviscid transonic flow applications for real geometries. -
Mathematical Problems in Transonic Flow
Canad. Math. Bull. Vol. 29 (2), 1986 MATHEMATICAL PROBLEMS IN TRANSONIC FLOW BY CATHLEEN SYNGE MORAWETZ ABSTRACT. We present an outline of the problem of irrotational com pressible flow past an airfoil at speeds that lie somewhere between those of the supersonic flight of the Concorde and the subsonic flight of commercial airlines. The problem is simplified and the important role of modifying the equations with physics terms is examined. The subject of my talk is transonic flow. But before I can talk about transonics I must talk about flight in general. There are two ways of staying off the ground -— by rocket propulsion (the Buck Rogers mode) or by using the forces that permit gliding or for that matter sailing. Every form of man's flight is some compromise between these two extremes. The one that most mathematicians begin their learning on is incompressible, steady (no time dependence), irrotational, flow governed by (i) Conservation of mass with q the velocity, (what goes in comes out) div q = 0, (ii) Irrotationality, curl q = 0. The pressure is given by Bernoulli's law, p = p(\q\). These equations are equivalent to the Cauchy-Riemann equations and so lots of problems can be solved. But there is an anomaly — there is no drag and for that matter often no lift i.e. no net force on the object which for our purposes and from here on is a cross section of a wing. By taking a nonsymmetric cross section that has a cusp at the end and requiring that the flow has a finite velocity we obtain a flow with lift but still no drag.