Aerodynamic Design And Analysis For A Strut Braced Transport Aircraft Utilizing Slotted Natural Laminar Flow Airfoils
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Aerodynamic Design And Analysis For A Strut Braced Transport Aircraft Utilizing Slotted Natural Laminar Flow Airfoils
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Author : Leonard P. Metkowski
language : en
Publisher:
Release Date : 2023
Aerodynamic Design And Analysis For A Strut Braced Transport Aircraft Utilizing Slotted Natural Laminar Flow Airfoils written by Leonard P. Metkowski and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023 with categories.
This thesis performs a design study exploring the aerodynamic design of a strut-braced transport aircraft. Moving from classical lifting-line theory to modern Reynolds Averaged Navier Stokes methods, several design and analysis methods are used to better understand this configuration, which is designed to meet NASA's N+4 commuter transport goals. The use of a novel slotted airfoil, the S207, is incorporated from the start. Intended to achieve long runs of laminar flow, this airfoil was designed along with the strut-braced configuration presented in this work. Analysis of both the airfoil's sectional characteristics and its application to the planform are explored. Several other areas researched include the use of a lifting strut verses an aerodynamically feathered strut and the design of winglets on the high-span aircraft. The aerodynamically feathered strut is chosen for the configuration at hand, while winglets are predicted by classical methods to add approximately 3% to maximum efficiency. The configuration is further analyzed with the modern computational fluid dynamic solver, OVERFLOW. This Reynolds Averaged Navier-Stokes solver is coupled with the Amplification-Factor-Transport transition model for transonic laminar flow prediction. Several performance differences with both the two-dimensional airfoil, and three-dimensional configuration are quantified. For two-dimensional cruise cases, Euler methods predict approximately 15 counts less profile drag when compared to the Reynolds Averaged method. Increases in profile drag that are found in the Reynolds Averaged models are attributed to early transition on the airfoil fore-element. The Euler methods also show transition to move slowly forward on the upper surface at increasing angles of attack. In comparison, the RANS method has transition move rather rapidly forward, limiting the upper corner of the low-drag region. Three-dimensional comparisons include highlighting problem areas around the strut/wing juncture, along with differences in spanwise lift distributions due to the addition of winglets. Further discussion on the sectional pressure distributions and the resulting two-dimensionality of the flow on the slotted configuration due to the winglet is also presented. Overall efficiency gains predicted by RANS with the addition of the winglet is found to be approximately 5%.
Development Of An Unsteady Aero Elastic Framework For The Study Of A Slotted Natural Laminar Flow Airfoil
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Author : Auriane Bottai
language : en
Publisher:
Release Date : 2023
Development Of An Unsteady Aero Elastic Framework For The Study Of A Slotted Natural Laminar Flow Airfoil written by Auriane Bottai and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023 with categories.
The objective of this research is to develop a framework for the study of the aero-elastic behavior of a truss-braced, Slotted, Natural-Laminar Flow (SNLF) wing. This type of airfoil emerged in the 2010s as a solution to significantly increase the lift coefficient while reducing the overall drag. It is composed of two encapsulated airfoils, separated by a small gap, or slot. Unlike an airfoil equipped with a flap, the aft element of such airfoil remains fixed. The aft element alleviates the pressure recovery requirement at the trailing edge of the fore element, thereby significantly extending the laminar flow region on the fore element. On the other hand, truss braced wings typically have longer span than conventional wings, which drives down the induced drag of the overall aircraft. This is permitted by the truss which adds structural reinforcement and alleviates the larger root bending moment arising from the longer span configuration. Earlier studies have found that combining those technologies for a new wing design has the potential of drastically reducing commercial aircraft fuel consumption. The present work is composed of fours parts: the first part consists of developing of an aero-elastic framework capable of predicting the aero-elastic stability of the wing. This tool is developed in time domain and proceeds by calculating the eigenvalues of the aero-elastic system. The signs of the real part of those eigenvalues determines whether the structure is stable or not. This tool is tested and validated on a classic wing configuration, the Goland wing. The second part is dedicated to the modal analysis and static stability of the \acl{snlf} wing. For this purpose, a \acl{fem} of the wing is developed. Connectors between the two airfoils are added in the geometry to maintain the profile integrity under external loading. Modal analysis with a various number of connectors showed that 13 or more connectors lead to similar mode shapes but the more connectors, the higher the natural frequencies. Fewer connectors result in significant wing deformation and deformation of the airfoil profile. \par The initial aero-elastic tool developed in this work models the two-element wing as two rectangular wings with no inter-element aerodynamic coupling. This weakness is overcome by an extensive steady flow analysis of the baseline Slotted, Natural-Laminar Flow airfoil as well as six deformed configurations in which the aft element is slightly moved upstream, downstream, upwards, downwards and rotated. This steady analysis showed that the contraction or dilatation of the gap can significantly affect the airfoil performance.Those effects are aggravated with increased Mach numbers and/or higher angle-of-attack. Conversely, if the aft element is rotated in a way that preserves the gap width, the aerodynamic coefficients remain nearly unchanged. The results of this sensitivity study are next integrated in the initially aero-elastic framework to study the aerodynamic stability of the \acl{snlf} wing, with various number of connectors. It is found that at least 13 connectors are needed to remain in the linear regime of variations of the aerodynamic coefficients. This is also the minimum number of connectors for the wing to remain stable. Finally, the behavior of the Slotted, Natural-Laminar Flow airfoil under unsteady circumstances is analyzed via a singularity based, Lagrangian method. Linear-varying strength vortex elements are distributed on the airfoil and complemented with other types of discrete singularities. The later enables corrections to the pressure coefficient and thereby the lift and moment coefficients and match the steady state loads predicted by a higher resolution flow solver. Unsteady aerodynamic coefficients up to a reduced frequency of unity of the Slotted, Natural-Laminar Flow wing with respect to vertical, chord-wise and rotational displacements of the fore and aft elements are generated with the linear-varying strength vortex method. The unsteady procedure with corrective singularities is tested on a symmetric thin airfoil and provides encouraging results. The corrective singularities are found to successfully correct the mean values of the lift coefficient but also affect the amplitude of lift and moment oscillations.
Government Reports Announcements Index
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Author :
language : en
Publisher:
Release Date : 1981
Government Reports Announcements Index written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1981 with Science categories.
Aeronautical Engineering
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Author :
language : en
Publisher:
Release Date : 1982
Aeronautical Engineering written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1982 with Aeronautics categories.
A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).
The Aerodynamic Design Of Wings With Cambered Span Having Minimum Induced Drag
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Author : Clarence D. Cone (Jr.)
language : en
Publisher:
Release Date : 1963
The Aerodynamic Design Of Wings With Cambered Span Having Minimum Induced Drag written by Clarence D. Cone (Jr.) and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1963 with Airplanes categories.
"The basic aerodynamic relations needed for the design of wings with cambered span having a minimum induced drag at specified flight conditions are developed for wings of arbitrary spanwise camber. Procedures are also developed for determining the physical wing form required to obtain the maximum value of lift-drag ratio at cruise, when the wing spanwise camber-line and section profiles are specified, by optimizing the wing chord and twist distributions with respect to both profile and induced drags. The application of the design procedure is illustrated by determining the physical wing form for a circular-arc spanwise camber line. The efficiency of this cambered wing is compared with that of an equal-span, flat wing of elliptical planform which satisfies the same set of fright operating conditions as does the cambered wing. The wing pitching- moment equations for optimally loaded cambered-span wings at design flight conditions are also developed for use in trim analyses on complete aircraft designs."--Page 1.
Special Course On Inverse Methods For Airfoil Design For Aeronautical And Turbomachinery Applications
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Author :
language : en
Publisher:
Release Date : 1990
Special Course On Inverse Methods For Airfoil Design For Aeronautical And Turbomachinery Applications written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1990 with Aerodynamics categories.
"This lecture series is devoted to major aspects of aerofoil design both for aeronautical and turbomachine application. These include: (1) optimisation of target pressure and velocity distribution. Both direct optimisation resulting from an inverse boundary layer calculation and an iterative optimisation of the loses are presented. (2) aerofoil design by means of inverse methods. This ranges from simple parametric definitions of two- dimensional cross sections to a detailed numerical definition of three dimensional shapes. blade or airfoil designs are normally made in two steps, and the lectures are accordingly grouped into two parts. First, optimisation of target pressure and velocity distributions are discussed taking into account the required performance and the lost mechanisms in the boundary layer. Both direct optimisation resulting from an inverse boundary layer calculation, and an iterative optimisation by minimisation of the losses are presented. It is clear from both procedures that inclusion of off-design operation is one of the greatest difficulties involved in blade or airfoil operation. The second part gives an overview of the numerous inverse blade design methods that have been developed both for turbomachinery and aeronautical applications. This ranges from simple parameter definitions of two-dimensional cross-sections to the full three-dimensional definition of wings and blade channels."--DTIC
Advanced Aircraft Design
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Author : Egbert Torenbeek
language : en
Publisher: John Wiley & Sons
Release Date : 2013-05-28
Advanced Aircraft Design written by Egbert Torenbeek and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-05-28 with Technology & Engineering categories.
Although the overall appearance of modern airliners has not changed a lot since the introduction of jetliners in the 1950s, their safety, efficiency and environmental friendliness have improved considerably. Main contributors to this have been gas turbine engine technology, advanced materials, computational aerodynamics, advanced structural analysis and on-board systems. Since aircraft design became a highly multidisciplinary activity, the development of multidisciplinary optimization (MDO) has become a popular new discipline. Despite this, the application of MDO during the conceptual design phase is not yet widespread. Advanced Aircraft Design: Conceptual Design, Analysis and Optimization of Subsonic Civil Airplanes presents a quasi-analytical optimization approach based on a concise set of sizing equations. Objectives are aerodynamic efficiency, mission fuel, empty weight and maximum takeoff weight. Independent design variables studied include design cruise altitude, wing area and span and thrust or power loading. Principal features of integrated concepts such as the blended wing and body and highly non-planar wings are also covered. The quasi-analytical approach enables designers to compare the results of high-fidelity MDO optimization with lower-fidelity methods which need far less computational effort. Another advantage to this approach is that it can provide answers to “what if” questions rapidly and with little computational cost. Key features: Presents a new fundamental vision on conceptual airplane design optimization Provides an overview of advanced technologies for propulsion and reducing aerodynamic drag Offers insight into the derivation of design sensitivity information Emphasizes design based on first principles Considers pros and cons of innovative configurations Reconsiders optimum cruise performance at transonic Mach numbers Advanced Aircraft Design: Conceptual Design, Analysis and Optimization of Subsonic Civil Airplanes advances understanding of the initial optimization of civil airplanes and is a must-have reference for aerospace engineering students, applied researchers, aircraft design engineers and analysts.
Laminar Flow Control Technology
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Author :
language : en
Publisher:
Release Date : 1979
Laminar Flow Control Technology written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1979 with Aircraft industry categories.
Low Reynolds Number Aerodynamics
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Author : Thomas J. Mueller
language : en
Publisher: Springer Science & Business Media
Release Date : 2013-03-08
Low Reynolds Number Aerodynamics written by Thomas J. Mueller and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-03-08 with Science categories.
Current interest in a variety of low Reynolds number applications has focused attention on the design and evaluation of efficient airfoil sections at chord Reynolds numbers from about 100,000 to about 1,000,000. These applications include remotely piloted vehicles (RPVs) at high altitudes, sailplanes, ultra-light man-carrying/man powered aircraft, mini-RPVs at low altitudes and wind turbines/propellers. The purpose of this conference was to bring together those researchers who have been active in areas closely related to this subject. All of the papers presented are research type papers. Main topics are: Airfoil Design and Analysis, Computational Studies, Stability and Transition, Laminar Separation Bubble, Steady and Unsteady Wind Tunnel Experiments and Flight Experiments.
The Two Dimensional Effects Of Slipstream Shear On Airfoil Characteristics
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Author : Robert J. Vidal
language : en
Publisher:
Release Date : 1960
The Two Dimensional Effects Of Slipstream Shear On Airfoil Characteristics written by Robert J. Vidal and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1960 with Aerofoils categories.