Pdf an optimization design method for a supercritical wing is developed. The airfoil used in this study is the nasa sc20714, which is a 14percentthick phase 2 supercritical airfoil with a design lift coefficient of 0. Whitcomb national aeronautics and space administration langley research center hampton, virginia abstract nasa supercritical airfoils are characterized by a substantially reduced curvature of the midchord region of the upper surface together with increased camber near the trailing edge. Lifting symmetric supercritical airfoils for wing design. Aerodynamic characteristics determined from twodimensional windtunnel tests at. Computer programs were developed in the early 1970s to produce the ordinates for airfoils of any thickness, thickness distribution, or camber in the naca airfoil series. May 02, 2019 one sheet is with non dimensional coordinates rswnd to be able to compare with other supercritical airfoils. Whitcomb 19212009, whom many historians of aviation call the most distinguished alumnus of the nasa langley research center. A supercritical aerofoil is an aerofoil that, principally, has been designed to delay the onset of wave drag in the transonic speed range. Pdf theory of wing sections download full pdf book download. Uiuc airfoil coordinates database university of illinois. Machine learning algorithms may be categorized into supervised, unsupervised, and semisupervised, depending on the extent and type of information available for the learning process. Instead of manual population control, the socalled pressure distribution. Computer programs were developed in the dx early 1970s to produce the ordinates for airfoils of any thickness, thickness distribution, or camber in.
The purpose of this report is to summarize the background of the nasa supercritical airfoil development, to discuss some of the airfoil design guidelines, and to present coordinates of a matrix of familyrelated supercritical airfoils with thicknesses. Included below are coordinates for nearly 1,600 airfoils version 2. Kawalki in germany in 1940, and british airfoil research resulted in similar shapes, first used in the vc10, he transferred some of their characteristics to a ga airfoil, the gaw1. Wake measurements of oscillating supercritical airfoil in. Sc20714 supercritical airfoil coordinates from raymer w one correction these coordinates are actual model coordinates, not coordinates as designed. Wave processes on a supercritical airfoil springerlink. Supercritical water conversion of biomass to biofuels represents an alternative path to acid hydrolysis and enzymatic hydrolysis. Pdf 3145 k wake measurements of oscillating supercritical airfoil in compressible flow. The supercritical airfoil also increases m crit at offdesign section lift coefficients. Transonic flow fields are considered where selfexcited shock wave oscillation prevails.
High fidelity gust simulations over a supercritical airfoil. The pressure coefficient distribution over the top surface of a supercritical airfoil flying above m cr but below m is sketched in fig. An experimental investigation of a supercritical airfoil at. Aerodynamics the supercritical airfoil the area rule delta wing leading edge extension lex 37. Us3952971a airfoil shape for flight at subsonic speeds. Download the dat file data in various formats or use the dat file data in the tools. Gb1601631a gb735278a gb735278a gb1601631a gb 1601631 a gb1601631 a gb 1601631a gb 735278 a gb735278 a gb 735278a gb 735278 a gb735278 a gb 735278a gb 1601631 a gb1601631 a gb 1601631a authority gb united kingdom prior art keywords profile profile depth depth maximum curvature prior art date 19770323 legal status the legal status is an assumption and is not a legal. Supercritical airfoils are characterized by their flattened upper surface, highly cambered downwardcurved aft section, and larger leadingedge radius compared with naca 6. Several groups of new airfoil sections, designated as the naca 8series, are derived analytically to have lift characteristics at supercritical mach numbers which are favorable in the sense that the abrupt loss of lift, characteristic of the usual airfoil section at mach numbers above the critical, is avoided. Airfoil design in subcritical and supercritical flows.
Supercritical airfoils are shaped to substantially reduce the strength of the shock wave and to delay the associated boundarylayer separation illustration b. To control the shock oscillation, a passive technique in the form of an open rectangular cavity is introduced on the upper surface of the airfoil where the shock wave oscillates. The naca airfoil series the early naca airfoil series, the 4digit, 5digit, and modified 45digit, were generated using analytical equations that describe the camber curvature of the meanline geometric centerline of the airfoil section as well as the sections thickness distribution along the. Jul 03, 2019 ice formation on a wing poses threats to aircraft safety because it changes the effective shape of the airfoil and deteriorates its lift and moment performances dramatically. To allow the normal shock wave to occur where the upper surface pressure gradient is favorable b. Supercritical wing design for combat aircraft nalir. Therefore, reynolds number has great effects on the economy, comfort and even safety of large aircrafts. Unsteady boundary layer measurement on an oscillating. Numerical study of a supercritical airfoilwing with. The supercritical wing was one of three major contributions langley research center engineer richard whitcomb made to aeronautics. Aerodynamic parameters analysis of transonic flow past unswept. Throughout this text, there will be crossreferences to other parts of the manual, as well as hyperlinks to web pages. A highly cambered trailing edge section improves overall airfoil lifting efficiency. Schematic of the flow field over supercritical airfoil finally the critical mach number m cr and drag divergence mach number m dd is increased by the shape of the supercritical airfoil.
Numerical study of a supercritical airfoilwing with variable. Figure 71, taken from the classic training manual, aerodynamics for naval aviators,2 shows the. Experienced supercritical wing designers usually do not seek a wing with the. The main goal of the proposed paper is the analysis of aerodynamic. Offset of shock location in supercritical airfoils irjet. The latest version of the manual will always be available from the x. Experiments on heavepitch limitcycle oscillations of a. Sc20714 supercritical airfoil coordinates from raymer. This handbook is a sequel to an earlier volume entitled a theory of supercritical wing sections, with computer programs and examples. Upstream moving pressure waves are observed in experiment as well as in numerical simulation of a supercritical airfoil flow for different flow regimes. A supercritical airfoil is an airfoil designed primarily to delay the onset of wave drag in the transonic speed range.
For turbojetpowered aircraft, which enjoy a propulsive efficiency proportional to the flight mach number, the overall aircraft efficiency. Since the completion of the first volume, which we shall refer to as volume i cf. One sheet is with non dimensional coordinates rswnd to be able to compare with other supercritical airfoils. The aerodynamic characteristics of an 11 percent thick symmetrical supercritical airfoil were determined in an 8 foot transonic pressure tunnel over a mach number range of 0. To give some idea of the practical benefit of the supercritical airfoil, air force and nasa researchers under the auspices of the transonic aircraft technology tact program modified a basic f111 bomber and replaced the existing naca 64210 wing airfoil with a supercritical shape of equal thickness. In this work, the supercritical airfoil configuration is analyzed by changing its position of camber in order to increase its lift coefficient and reduce the drag. At present, there is considerable interest in supercritical wing technology for the development of aircraft designed to fly near the speed of sound. The other sheet rectsupercriticalwing has the data which should be used to generate the grids. Integral supercritical airfoil it was recognized that the presence of a slot. If you would like some more background on the subject, feel free to watch the following.
An aftloaded section, the opposite of a reflexed airfoil carries more lift over the aft part of the airfoil. Called the supercritical airfoil, the design has led to development of the supercritical wings scw. An airfoil having an upper surface shaped to control flow accelerations and pressure distribution over the upper surface and to prevent separation of the boundary layer due to shock wave formulation at high subsonic speeds well above the critical mach number. Thepressure distribution obtained using the bgkj codeis. Comparison of supercritical airfoil flow calculations with. An eccentric who seemed most at home in the centers wind tunnel facilities, where he was known to sometimes sleep between double shifts, whitcomb tended to prefer intuition to calculation when working out designs.
It is 114% thick, with maximum thickness at 36% chord. Supercritical water reactor scwr, a generation iv nuclear reactor concept that uses supercritical water as the working fluid. The design coordinates from reference 6 for this airfoil arc listed in table 1. Supercritical flow, where flow velocity is larger than wave velocity supercritical airfoil, an airfoil designed to delay the onset of. The supercritical airfoil supercritical wings add a graceful appearance to the modified nasa f8 test aircraft.
This paper deals with the use of lifting symmetric supercritical airfoils in the wing design of a combat aircraft. Supercritical airfoils are characterized by their flattened upper surface. A twodimensional numerical investigation was performed to determine the effect of an active gurney flap on an oscillating supercritical rae 2822 airfoil in transonic flow. Aerodynamics the supercritical airfoil the area rule delta. Pdf theory of wing sections download full pdf book. Links to the original data source for more information. Pdf supercritical wing design based on airfoil optimization and. The aerodynamic characteristics of supercritical airfoil are rather sensitive to reynolds number. The uiuc airfoil data site gives some background on the database. Typical features of supercritical aerofoils, when compared to traditional aerofoil shapes, are a flattened upper surface, a highly cambered or curved aft section and greater leading edge radius. For transonic combat aircraft requiring supersonic accele. Control of transonic shock wave oscillation over a. Results from flutter experiments of the supercritical airfoil nlr 7301 at flow conditions near the transonic dip are presented.
Since the airfoil shape allows efficient flight at supercritical flight speeds, a wing of such design is called a supercritical wing. Supercritical airfoil as an aircraft approaches the speed of sound, it reaches a point where the air flowing over the wings reaches supersonic speeds though the plane itself is still moving slower than mach 1, causing a dramatic increase in drag. Numerical investigation on the reynolds number effects of. Download now at present, there is considerable interest in supercritical wing technology for the development of aircraft designed to fly near the speed of sound. Downloaded by bristol university on july 12, 2018 doi. Optimization of supercritical airfoil considering the ice. American institute of aeronautics and astronautics 12700 sunrise valley drive, suite 200 reston, va 201915807 703. Aerodynamic characteristics determined, from twodimensional windtunnel tests at. Numerical simulation of harmonic pitching supercritical. Airfoil, drag divergence mach number, leading edge.
Computer program to obtain ordinates for naca airfoils. An experimental investigation of a supercritical airfoil. A comparison of the supercritical flow phenomena for the nasa supercritical airfoil and an naca 6 series airfoil at the cruise lift coefficient is presented in figure 2. A supercritical airfoil is an airfoil designed primarily to delay the onset of wave drag in the. This result of the supercritical airfoil is compared with respective to the seven digit airfoil. Unsteady boundary layer measurement on an oscillating pitching supercritical airfoil in compressible flow using multiple hotfilm sensors aa haghiri, m mani, and n fallahpour proceedings of the institution of mechanical engineers, part g. Experimental and numerical investigation into the wake of. The trailingedge variablecamber region starts from xc 0. Supercritical wing sections ii a handbook felix bauer. Benchmark supercritical wing are available in pdf file of tables.
To arrive at this airfoil, the flow past naca 0012 airfoil atmoo 0752 and incidence equal to 11 degrees was considered. The airspeed at which this occurs is called the critical mach number for the wing. Supercritical airfoil has been widely applied to large aircrafts for sake of high aerodynamic efficiency. Comparison of computational and experimental results for a. In the present study, a numerical investigation is carried out on the aerodynamic performance of a supercritical airfoil rae 2822. Experimental investigations were carried out to study the wake characteristics of a pitching supercritical airfoil at mach number of 0. At speeds in the transonic range just below and just above the speed of sound the scw delays the formation of the supersonic shock wave on the upper wing. The development of cambered airfoil sections having.
The development of supercritical airfoils is explained from a historic perspective. Hybrid optimization design of naturallaminarflownlf. The present study develops a supercritical airfoil optimization design method that takes into account the iceaccretion effects. Boundary layer condition, and the related phenomena, depends on such different parameters as the oscillation type, flight mach number, angle of attack, etc. Airfoils and wings the primary lifting surface of an aircraft is its wing. Behnaz beheshti boroumand, a mahmoud mani a b a aerospace engineering department, amirkabir university of technology, tehran, iran b center of excellence on computational aerospace engineering, amirkabir university of technology, tehran, iran. What are the disadvantages if any of using a supercritical. Supercritical airfoil and wing design supercritical airfoil and wing design sobieczky, h. For transonic combat aircraft requiring supersonic acceleration, the usual supercritical airfoil which invariably has camber is not suitable because of the supersonic wave drag penalty arising from the camber. Aerodynamic characteristics of an 11percentthick symmetrical supercritical airfoil at mach numbers between 0. The aerodynamic characteristics of several supercritical airfoils interim to the improved 10percent thick nasa supercritical airfoil 26a are discussed. For the naca 6 series airfoil, as shown at the top of the figure, the supersonic flow accelerated to the shock wave located near the mid chord.
Surface pressures were measured on both the model and windtunnel walls. Supercritical airfoils are often referred to as one of the three major contributions to aviation made by the famous aerodynamicist richard t. Sc20714 supercritical airfoil coordinates from raymer w. This paper deals with the use of lifting symmetric super. Supercritical water can quickly convert cellulose to sugar and biomass into a mixture of oils, organic acids, alcohol, and methane.
The basic principle is the suppression of boundary layer separation by shifting the shock waves that occur on the wing toward the trailing edge and making them as weak as possible. The airfoil was mounted with two degreesoffreedom in an adaptive solidwall wind tunnel, and boundarylayer transition was tripped. Characteristics of a typical lifting symmetric supercritical. Further, limited experimental results confirming the theoretical inference are also presented. Supercritical wing design and optimization for transonic civil airplane. Jul 12, 20 a supercritical airfoil can be used to delay the onset of shocks, and thus enable faster cruising speeds. Ubiquitous supercritical wing design cuts billions in fuel costs. Supercritical airfoil article about supercritical airfoil.
The naca airfoil series the early naca airfoil series, the 4digit, 5digit, and modified 45digit, were generated using analytical equations that describe the camber curvature of the meanline geometric centerline of the airfoil section as well as the sections thickness distribution along the length of the airfoil. Nov 06, 2015 a supercritical airfoil is an airfoil designed, primarily, to delay the onset of wave drag in the transonic speed range. A shock tube with a rectangular test section is utilized to study the transonic flow about an airfoil model of a constant chord length. To design a symmetric lifting supercritical airfoil, we take a baseline airfoil which is symmetric. The airfoils are listed alphabetically by the airfoil filename which is usually close to the airfoil name. Supercritical airfoils are characterized by their flattened upper surface, highly cambered downwardcurved aft section, and larger leadingedge radius compared with naca 6series laminar airfoil shapes. Nasa photo e733468 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. The theoretical aerodynamic characteristics of a typical lifting symmetric supercritical airfoil demonstrating its superiority over the naca 0012 airfoil from which it was derived are presented in this paper. This airfoil has been obtained by modifying the naca 0012 airfoil. 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. The velocity field above the airfoil and the field in its wake was documented using a laser doppler velocimeter. Unusual airfoil design constraints can sometimes arise, leading to some unconventional shapes.
Whitcomb reinvented supercritical airfoils they had first be developed by k. An example of applying statistical inference and ml. Cfd analysis of supercritical airfoil with different camber. Subrahmanyan chandrasekhar 19101995 is justly famous for his lasting contributions to topics such as white dwarfs and black holes which led to his nobel prize, stellar structure and dynamics, general relativity, and other facets of astrophysics. Computed airfoil shapes using subcritical and supercritical pressure distributions obtained from existing finitedifference analysis codes, in the latter case, with and without shockwaves, give results in reasonable agreement with the original specified shapes, and validate the basic ideas. Aerodynamic characteristics of an airfoil in a dynamic motion are highly affected by the behavior of the viscous boundary layer. Pressure distribution guided supercritical wing optimization. The navierstokes code fluent was used to calculate the flow field around the airfoil using the shear stress transport turbulence model. The airfoil here was designed for an ultralight sailplane requiring very high maximum lift coefficients with small pitching moments at high speed. View the airfoil details page with polar diagrams for a range of reynolds numbers. Detailed experimental data were obtained on a supercritical airfoil and in the surrounding flowfield. If the wing is sliced with a plane parallel to the xz plane of the aircraft, the intersection of the wing surfaces with that plane is called an airfoil. Pdf supercritical wing design and optimization for transonic.