Control of Unsteady Separated Flow Associated with the Dynamic Pitching of Airfoils


Book Description

Although studies have been done to understand the dependence of parameters for the occurrence of deep stall, studies to control the flow for sustaining lift for a longer time has been little. To sustain the lift for a longer time, an understanding of the development of the flow over the airfoil is essential. Studies at high speed are required to study how the flow behavior is dictated by the effects of compressibility. When the airfoil is pitched up in ramp motion or during the upstroke of an oscillatory cycle, the flow development on the upper surface of the airfoil and the formation of the vortex dictates the increase in lift behavior. Vortex shedding past the training edge decreases the lift. It is not clear what is the mechanism associated with the unsteady separation and vortex formation in present unsteady environment. To develop any flow control device, to suppress the vortex formation or delay separation, it is important that this mechanism be properly understood. The research activities directed toward understanding these questions are presented and the results are summarized. Ahmed, Sajeer Unspecified Center...







Control of Unsteady Separated Flow Associated with the Dynamic Stall of Airfoils


Book Description

The two principal objectives of this research were to achieve an improved understanding of the mechanisms involved in the onset and development of dynamic stall under compressible flow conditions, and to investigate the feasibility of employing adaptive airfoil geometry as an active flow control device in the dynamic stall engine. Presented here are the results of a quantitative (PDI) study of the compressibility effects on dynamic stall over the transiently pitching airfoil, as well as a discussion of a preliminary technique developed to measure the deformation produced by the adaptive geometry control device, and bench test results obtained using an airfoil equipped with the device. Wilder, Michael C. Unspecified Center NCC2-637...













Atlas of Visualization


Book Description

Visualization is a novel interdisciplinary science for making any phenomenon clear by visualizing the invisible using computer techniques. The Atlas of Visualization presents the latest advances in visualization techniques, image processing, computer graphics, and visualization of measured and compound results. Focusing on both experimental and computer-aided visualization, this encyclopedic resource discusses all aspects of this new and evolving science. This volume includes cutting-edge information on turbulent flow, vortex, water spray, PIV, jet flames, thermal plume and numerical simulation, and heat and mass transfer. Encompasses all aspects of visualization! The Atlas of Visualization is concerned with all aspects of visualization, not just with engineering and physics applications, but with applications in disciplines such as the biomedical sciences, oceanography, agriculture, meteorology, and sports science. The aim of this book is to provide a medium for announcing the latest advances in visualization. Full color presentation! Books on visualization could not discuss complex phenomena without the use of color photographs. For this reason, the Atlas of Visualization is issued in full color. This allows the complex phenomena to be presented clearly, and combined phenomena are illustrated with quantitative results and detailed structure. Global perspective! The chapters and gravures in the Atlas are contributed by the world's top researchers, and provides both researchers and technicians with extremely useful information from the foremost innovators in the field of visualization. Computer scientists, mechanical engineers, physicists, applied and biological scientists, meteorologists, and sports scientists, as well as students of these disciplines, will find the Atlas of Visualization an essential source of all the latest knowledge in the field of visualization.




Experimental Heat Transfer, Fluid Mechanics and Thermodynamics 1993


Book Description

The papers contained in this volume reflect the ingenuity and originality of experimental work in the areas of fluid mechanics, heat transfer and thermodynamics. The contributors are drawn from 27 countries which indicates how well the worldwide scientific community is networked. The papers cover a broad spectrum from the experimental investigation of complex fundamental physical phenomena to the study of practical devices and applications. A uniform outline and method of presentation has been used for each paper.







Principles of Helicopter Aerodynamics


Book Description

Helicopters are highly capable and useful rotating-wing aircraft with roles that encompass a variety of civilian and military applications. Their usefulness lies in their unique ability to take off and land vertically, to hover stationary relative to the ground, and to fly forward, backward, or sideways. These unique flying qualities, however, come at a high cost including complex aerodynamic problems, significant vibrations, high levels of noise, and relatively large power requirements compared to fixed-wing aircraft. This book, written by an internationally recognized expert, provides a thorough, modern treatment of the aerodynamic principles of helicopters and other rotating-wing vertical lift aircraft. Every chapter is extensively illustrated and concludes with a bibliography and homework problems. Advanced undergraduate and graduate students, practising engineers, and researchers will welcome this thorough and up-to-date text on rotating-wing aerodynamics.