Supersonic flutter of flat rectangular orthtropic panels elastically restrained against edge rotation

Supersonic flutter analysis for flat loaded orthotropic panels with edge restrain

Transonic single-mode flutter and buffet of a low aspect ratio wing having a subsonic airfoil shape

Transonic flutter and buffet results obtained from wind-tunnel tests of a low aspect ratio semispan wing model are presented. The tests were conducted to investigate potential transonic aeroelastic problems of vehicles having subsonic airfoil sections. The model employed NACA 00XX-64 airfoil sections in the streamwise direction and had a 14 deg leading edge sweep angle. Aspect ratio, and average thickness were 4.0, 0.35, and 8 percent, respectively. The model was tested at Mach numbers from 0.6 to 0.95 at angles of attack from 0 deg to 15 deg. Two zero lift flutter conditions were found that involved essentially single normal mode vibrations. With boundary layer trips on the model, flutter occurred in a narrow Mach number range centered at about Mach 0.90. The frequency and motion of this flutter were like that of the first normal mode vibration. With the trips removed flutter occurred at a slightly high Mach number but in a mode strongly resembling that of the second normal mode

Simple method for forming thin-wall pressure vessels

Application of internal hydrostatic pressure to seam-welded circular cylindrical tanks having corner-welded, flat, circular ends forms large thin-walled high quality tanks. Form limits expansion of cylindrical portion of final tank while hemispherical ends develop freely; no external form or restraint is required to fabricate spherical tanks

Panel methods: An introduction

Panel methods are numerical schemes for solving (the Prandtl-Glauert equation) for linear, inviscid, irrotational flow about aircraft flying at subsonic or supersonic speeds. The tools at the panel-method user's disposal are (1) surface panels of source-doublet-vorticity distributions that can represent nearly arbitrary geometry, and (2) extremely versatile boundary condition capabilities that can frequently be used for creative modeling. Panel-method capabilities and limitations, basic concepts common to all panel-method codes, different choices that were made in the implementation of these concepts into working computer programs, and various modeling techniques involving boundary conditions, jump properties, and trailing wakes are discussed. An approach for extending the method to nonlinear transonic flow is also presented. Three appendices supplement the main test. In appendix 1, additional detail is provided on how the basic concepts are implemented into a specific computer program (PANAIR). In appendix 2, it is shown how to evaluate analytically the fundamental surface integral that arises in the expressions for influence-coefficients, and evaluate its jump property. In appendix 3, a simple example is used to illustrate the so-called finite part of the improper integrals

Labor Costs and the Social Dumping Debate in the European Union

This study examines the labor cost incentive for capital movement in manufacturing within the European Union, a key aspect of the social dumping debate in Western Europe. The authors find that the percentage differences in unit labor costs between the more developed and less developed countries in the Union not only were large in 1980 but actually grew between 1980 and 1986, and separate estimates of compensation and productivity growth rates do not indicate that significant convergence occurred over the remainder of the 1980s. Although these findings apparently confirm that a labor cost incentive for capital mobility does exist, analysis of foreign direct investment data indicates that during the period 1980-88 capital flows to the lower labor cost countries actually were not much larger than capital flows to the higher labor cost countries

Change and Transformation in Asian Industrial Relations

Authors argue that industrial relations systems change due to shifts in the constraints facing those systems, and that the most salient constraints facing IR systems in Asia have shifted from those of maintaining labor peace and stability in the early stages of industrialization, to those of increasing both numerical and functional flexibility in the 1980s and 1990s. The evidence to sustain the argument is drawn from seven “representative” Asian IR systems: Japan, South Korea, Singapore, Malaysia, the Philippines, India, and China. They also distinguish between systems that have smoothly adapted (Singapore, Malaysia, and the Philippines) and systems that have fundamentally transformed (China and South Korea), and hypothesize about the reasons for this difference

Industrial Relations System Transformation

This paper analyzes the concept of “transformation” that many allege has occurred recently in a wide variety of national industrial relations systems. After a summary of the debate, with particular reference to the contentious case of Germany, the authors attempt to develop a definition of industrial relations system transformation on the basis of biological analogies and, in particular, the “punctuated equilibrium” theory. They examine the cases of the United States, Sweden, South Africa, and New Zealand, and conclude that the application of the biological frameworks raises a set of fundamental questions that must be addressed in order for the debate over the existence of industrial relations transformation to move forward

PAN AIR analysis of the NASA/MCAIR 279-3: An advanced supersonic V/STOL fighter/attack aircraft

PAN AIR is a computer program for predicting subsonic or supersonic linear potential flow about arbitrary configurations. The program was applied to a highly complex single-engine-cruise V/STOL fighter/attack aircraft. Complexities include a close-coupled canard/wing, large inlets, and four exhaust nozzles mounted directly under the wing and against the fuselage. Modeling uncertainties involving canard wake location and flow-through approximation through the inlet and the exhaust nozzles were investigated. The recently added streamline capability of the program was utilized to evaluate visually the predicted flow over the model. PAN AIR results for Mach numbers of 0.6, 0.9, and angles of attack of 0, 5, and 10 deg. were compared with data obtained in the Ames 11- by 11-Foot Transonic Wind tunnel, at a Reynolds number of 3.69 x 10 to the 6th power based on c bar

FLEXSTAB: A computer program for the prediction of loads and stability and control of flexible aircraft

Capabilities of the FLEXSTAB Computer Program System are described and illustrated. Aeroelastic analysis of a wide variety of aircraft configurations is performed. The aerodynamic theory used in FLEXSTAB is applicable to both steady and unsteady, subsonic and supersonic flow for multiple wing-body tail nacelle configurations with a plane of symmetry. For unsteady flow calculations, an unsteady aerodynamic theory is used which is appropriate for the low reduced frequencies associated with aircraft flight dynamics. The aircraft is modeled as either a rigid or flexible structure. The computer trims the aircraft in steady reference flight and computes both static and dynamic stability and control derivatives and the stability behavior about the trim condition. The airplane lifting pressure distribution, aerodynamic and inertia loads and deflected shape are also computed