...March 14, 2012 [AEROELASTICITY MIDTERM PROJECT-FLUTTER ANALYSIS ] Objective: To conduct flutter analysis of a typical section model of an airfoil using the parameters as discussed in lecture. Consider both the case without the ̇ ̇ term and the case with the term in the aerodynamic model. Create the Eigen value plot for both the cases. Answer: Introduction to Flutter: Flutter is a dangerous phenomenon encountered in flexible structures subjected to aerodynamic forces. This includes aircraft, buildings, telegraph wires, stop signs and bridges. Flutter occurs as a result of interactions between aerodynamics, stiffness and inertial forces on a structure. In an aircraft, as the speed of the wind increases, there may be a point at which the structural damping is insufficient to damp out the motions which are increasing due to aerodynamic energy being added to the structure. This vibration can cause structural failure and therefore considering flutter characteristics is an essential part of designing an aircraft. ̇ Case 1 : Flutter Analysis when there is no additional term ( ) in the aerodynamic damping For the case of simplicity we consider the following typical section model Equations of motion for this model are: ̈ ̈ ̈ (E1) ̈ (E2) where m=modal mass matrix =static unbalance =moment of inertia =spring constant Page 1 [AEROELASTICITY MIDTERM PROJECT-FLUTTER ANALYSIS ] March 14, 2012 =constant of torsional spring =displacement...
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...5 Aircraft Load 5.1 Overview Aircraft structures must withstand the imposed load during operations; the extent depends on what is expected from the intended mission role. The bulkiness of the aircraft depends on its structural integrity to withstand the design load level. The heavier the load, the heavier is the structure; hence, the MTOW affecting aircraft performance. Aircraft designers must comply with mandatory certification regulations to meet the minimum safety standards. This book does not address load estimation in detail but rather continues with design information on load experienced by aircraft. Although the information provided herein is not directly used in configuring aircraft, the knowledge and data are essential for understanding design considerations that affect aircraft mass (i.e., weight). Only the loads and associated V-n diagram in symmetrical flight are discussed herein. It is assumed that designers are supplied with aircraft V-n diagrams by the aerodynamics and structures groups. Estimation of load is a specialized subject covered in focused courses and textbooks. However, this chapter does outline the key elements of aircraft loads. Aircraft shaping dictates the pattern of pressure distribution over the wetted surface that directly affects load distribution. Therefore, aircraft loads must be known early enough to make a design “right the first time.” 5.1.1 What Is to Be Learned? This chapter covers the following topics: Section 5.2: Introduction to...
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...Shock Waves (2009) 19:453–468 DOI 10.1007/s00193-009-0220-z ORIGINAL ARTICLE Some physical aspects of shock wave/boundary layer interactions Jean Délery · Jean-Paul Dussauge Received: 9 February 2009 / Accepted: 29 June 2009 / Published online: 26 July 2009 © Springer-Verlag 2009 Abstract When the flow past a vehicle flying at high velocity becomes supersonic, shock waves form, caused either by a change in the slope of a surface, a downstream obstacle or a back pressure constraining the flow to become subsonic. In modern aerodynamics, one can cite a large number of circumstances where shock waves are present. The encounter of a shock wave with a boundary layer results in complex phenomena because of the rapid retardation of the boundary layer flow and the propagation of the shock in a multilayered structure. The consequence of shock wave/ boundary layer interaction (SWBLI) are multiple and often critical for the vehicle or machine performance. The shock submits the boundary layer to an adverse pressure gradient which may strongly distort its velocity profile. At the same time, in turbulent flows, turbulence production is enhanced which amplifies the viscous dissipation leading to aggravated performance losses. In addition, shock-induced separation most often results in large unsteadiness which can damage the vehicle structure or, at least, severely limit its performance. The article first presents basic and well-established results on the physics of SWBLI corresponding to...
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...THESIS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY Six Sigma Management Action research with some contributions to theories and methods PETER CRONEMYR Division of Quality Sciences Department of Technology Management and Economics CHALMERS UNIVERSITY OF TECHNOLOGY Göteborg, Sweden (2007) They wanted me to be respected as A doctor or a lawyer man But I had other plans Gonna be a rock ‘n’ roll singer Gonna be a rock ‘n’ roll star AC/DC - Rock ‘n’ Roll Singer Young/Young/Scott 1975 No matter what Quality will keep on rockin’ The Rock Stars of Quality Debbie Phillips-Donaldson, editor Quality Progress, July 2005 Six Sigma Management Action research with some contributions to theories and methods Peter Cronemyr Copyright © Peter Cronemyr (2007) ISBN 978-91-7385-021-6 Doktorsavhandlingar vid Chalmers tekniska högskola Ny serie nr 2702 ISSN: 0346-718X Published and distributed by: Division of Quality Sciences CHALMERS UNIVERSITY OF TECHNOLOGY S-412 96 Göteborg, Sweden Telephone: +46 (0)31 772 10 00 Printed at: Chalmers Reproservice Göteborg, Sweden Thesis Shortcuts Six Sigma A short introduction Go directly to Chapter 3.1 on page 47 Action Research Methodology Go directly to Chapter 2.2 on page 28 The Author Background and motives Go directly to Chapter 1.2 on page 15 Siemens Industrial Turbomachinery AB The Case Company Go directly to Appendix A, Chapter 2.1 on page A-3 The Conclusions of the Thesis Go directly to Chapter 5 on page 89 ...
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