Download or read book Investigation of Co Flow Jet Flow Control and Its Applications written by Alexis Michel Lefebvre and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates the performance of co-flow jet (CFJ) flow control and its applications using experimental testing and computational fluid dynamics (CFD) simulations. First, the study examines the CFJ energy expenditure, lift enhancement, drag reduction, stall margin increase, dynamic stall removal, and performance variation with Mach number. These investigations are conducted for a variety of stationary airfoils, pitching airfoils, and 3D CFJ wings. Then, the CFJ airfoil is applied to design an ultra-high wing loading general aviation electric airplane (EA). For a stationary airfoil and wing, CFJ increases the lift coefficient (CL), reduces the drag and may produce thrust at a low angle of attack (AoA). The maximum lift coefficient is substantially increased for a 2D CFJ airfoil and reaches a value of 4.8 at C[mu] = 0.30. The power consumption of the CFJ pump, measured by the power coefficient (Pc), is influenced by a variety of parameters, including themomentum coefficient (C[mu] ), the AoA, the injection slot location, and the internal cavity configuration. A low C[mu] of 0.04 produces a rather small Pc in the range of 0.01 - 0.02 while a higher C[mu] rapidly increases the Pc. Due to the stronger leading edge suction effect, increasing the AoA decreases the Pc. That is until the flow is near separation, within about 2°- 3° of the stall AoA. An injection slot location within 2% - 5% chord from the leading edge very effectively reduces the power coefficient since the leading edge suction effect is typically the strongest within this range. An internal cavity design with no separation is crucial to minimize the CFJ power consumption. When the Mach number is increased from 0.03 to 0.3, the suction pressure behind the airfoil leading edge is lowered due to the compressibility effect. This increases the CFJ airfoil maximum lift coefficient and decreases the power coefficient because of the lower required jet injection pressure. The drag coefficient remains fairly stable within this range of Mach numbers. At Mach 0.4, as the AoA increases, the flow on the suction surface becomes transonic. Consequently, a strong shock wave interrupts the jet and triggers a boundary-layer separation. The shock wave boundary-layer interaction and wave drag increase the total drag and the power coefficient significantly due to a large increase in entropy. Overall, the CFJ effectiveness is enhanced with an increasing Mach number as long as the flow remains subsonic, typically with free stream Mach number less than 0.4. For a pitching airfoil, CFJ is able to remove the dynamic stall with a substantial lift increase and drag decrease. Two pitching airfoil oscillations with dynamic stall are studied in this thesis, namely the mild dynamic stall and the deep dynamic stall. At Mach 0.3, the CFJ with a relatively low C[mu] of 0.08 removes the mild dynamic stall. Thereby, the timeaveraged lift is increased by 32% and the time-averaged drag is decreased by 80%. The resulting time-averaged aerodynamic (L/D)ave, which does not take the pumping power into account, reaches 118.3. When C[mu] is increased, the time-averaged drag becomes negative, which demonstrates the feasibility of a CFJ to propel helicopter blades using its pump as the only source of power. The deep-stall is mitigated at C[mu] = 0.12 and completely removed at C[mu] = 0.20 with a great (L/D)ave increase. At Mach 0.4, the CFJ mitigates the mild dynamic stall. However, the energy consumption is higher than at Mach 0.3 due to the appearance of shock waves in the flow. A 3D CFJ wing based on NACA 6415 airfoil with an aspect ratio of 20 produces a maximum L/D of 38.5 at a remarkably high cruise CL of 1.20 with an AoA of 5.0° and a low C[mu] of 0.04. The takeoff and landing performance is also excellent with a maximum CL of 4.7 achieved at C[mu] of 0.28 and AoA of 40.0°. When the wing thickness is increased from 15% to 21%, not only the lift is increased by about 5% but the structural strength is also improved. Overall the CFJ wing efficiency is found to be similar to that of conventional wings, but the lift coefficient at cruise condition is much higher, typically by 2-3 times. Hence CFJ is particularly suitable to design a compact wing with high wing loading. In the final study of this thesis, a CFJ Electric Aircraft (CFJ-EA) is designed for the general aviation. The aircraft has a high wing loading so that it can carry more battery and reach a longer range with a relatively small wing size. The CFJ-EA mission is to carry 4 passengers at a cruise Mach number of 0.15 with a range of 315nm. The CFJ-EA cruises at a very high CL of 1.3, which produces a wing loading of 182.3kg/m2, about 3 times higher than that of a conventional general aviation airplane. To determine the aircraft range and endurance, we introduce the corrected aerodynamic efficiency (L/D)c defined as (L/D)c = L/(D+P/Vinf), where the L and D are the aerodynamic lift and drag, P is the CFJ pumping power and Vinf is the free stream velocity. The (L/D)c of the CFJ-EA is excellent with a cruise value of 23.5 at a low C[mu] of 0.04. Takeoff and landing distances are also good due to a very high maximum CL of 4.8, achieved with a high C[mu] of 0.28. During takeoff and landing, the wing pivots around its 1/4 chord axis so that it can achieve an AoA of 25.0° with the fuselage rotated by only 5.0°. Based on a measure of merit defined as MPS=Miles*Passengers/S, where S is the wing planform area, the MPS of the present EA design is about half that of a conventional reciprocating engine general aviation airplane, and is 1.5 to 2.5 times greater than the MPS of the state of the art EA. This suggests that, compared to the conventional EA, a same size CFJ-EA has a far greater range, or a smaller CFJ-EA achieves the same range. Therefore, the CFJ-EA concept may open the door to a new class of general aviation EA designs. The same CFJ airfoil flow control technology is also suitable for airplanes and rotorcraft using conventional propulsion systems including high altitude planform, general aviation, commercial aviation or military transport to improve the range, reduce the wing size and/or reduce the takeoff and landing distances.

Download or read book Flow Control Techniques and Applications written by Jinjun Wang and published by Cambridge University Press. This book was released on 2019 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: Master the theory, applications and control mechanisms of flow control techniques.

Download or read book Applications of Circulation Control Technologies written by Ronald Douglas Joslin and published by AIAA (American Institute of Aeronautics & Astronautics). This book was released on 2006 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on papers from the 2004 NASA/ONR Circulation Control Workshop, this collection is an invaluable, one-of-a-kind resource on the state of the art in circulation control technologies and applications. Filling the information gap between 1986 -- when the last such symposium was held -- and today, it summarizes the applications, experiments, computations and theories related to circulation control, emphasizing fundamental physics, systems analysis and applied research. The papers presented cover a wide variety of aerodynamic and hydrodynamic applications including naval vehicles, fixed-wing aviation, V/STOL platforms, propulsion systems and ground vehicles. Anyone with interests in applied aerodynamics, fluid mechanics and aircraft design will find this book of particular value, as will those seeking a an up-to-date reference work on circulation control and its many current applications.

Download or read book Morphing Wing Technologies written by Sergio Ricci and published by Butterworth-Heinemann. This book was released on 2017-10-27 with total page 970 pages. Available in PDF, EPUB and Kindle. Book excerpt: Morphing Wings Technologies: Large Commercial Aircraft and Civil Helicopters offers a fresh look at current research on morphing aircraft, including industry design, real manufactured prototypes and certification. This is an invaluable reference for students in the aeronautics and aerospace fields who need an introduction to the morphing discipline, as well as senior professionals seeking exposure to morphing potentialities. Practical applications of morphing devices are presented—from the challenge of conceptual design incorporating both structural and aerodynamic studies, to the most promising and potentially flyable solutions aimed at improving the performance of commercial aircraft and UAVs. Morphing aircraft are multi-role aircraft that change their external shape substantially to adapt to a changing mission environment during flight. The book consists of eight sections as well as an appendix which contains both updates on main systems evolution (skin, structure, actuator, sensor, and control systems) and a survey on the most significant achievements of integrated systems for large commercial aircraft. - Provides current worldwide status of morphing technologies, the industrial development expectations, and what is already available in terms of flying systems - Offers new perspectives on wing structure design and a new approach to general structural design - Discusses hot topics such as multifunctional materials and auxetic materials - Presents practical applications of morphing devices

Download or read book Frontiers of Engineering written by National Academy of Engineering and published by National Academies Press. This book was released on 2002-10-10 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: This collection includes summaries of presentations given at the NAE Symposium in March 2001. Topics include flight at the leading edge, civil systems, wireless communications, and technology and the human body

Download or read book Flow Control written by Mohamed Gad-el-Hak and published by Cambridge University Press. This book was released on 2000-08-15 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: A thorough treatment of the basics of flow control and flow control practices.

Download or read book Fundamentals of High Lift for Future Civil Aircraft written by Rolf Radespiel and published by Springer Nature. This book was released on 2020-10-17 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reports on the latest numerical and experimental findings in the field of high-lift technologies. It covers interdisciplinary research subjects relating to scientific computing, aerodynamics, aeroacoustics, material sciences, aircraft structures, and flight mechanics. The respective chapters are based on papers presented at the Final Symposium of the Collaborative Research Center (CRC) 880, which was held on December 17-18, 2019 in Braunschweig, Germany. The conference and the research presented here were partly supported by the CRC 880 on “Fundamentals of High Lift for Future Civil Aircraft,” funded by the DFG (German Research Foundation). The papers offer timely insights into high-lift technologies for short take-off and landing aircraft, with a special focus on aeroacoustics, efficient high-lift, flight dynamics, and aircraft design.

Download or read book IUTAM Symposium on Flow Control and MEMS written by Jonathan F. Morrison and published by Springer Science & Business Media. This book was released on 2010-09-09 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Symposium brought together many of the world’s experts in fluid mechanics, microfabrication and control theory to discover the synergy that can lead to real advances and perhaps find ways in which collaborative projects may proceed. The high profile meeting was attended by keynote speakers who are leaders in their fields. A key driver was the improvement in flow efficiency to reduce drag, and thereby emissions arising from transport. About 65 papers were presented.

Download or read book Internal Flow written by E. M. Greitzer and published by Cambridge University Press. This book was released on 2007-02-26 with total page 739 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the analysis and behaviour of internal flows encountered in propulsion systems, fluid machinery (compressors, turbines and pumps) and ducts (diffusers, nozzles and combustion chambers). The focus is on phenomena that are important in setting the performance of a broad range of fluid devices. The authors show that even for complex processes one can learn a great deal about the behaviour of such devices from a clear understanding and rigorous use of basic principles. Throughout the book they illustrate theoretical principles by reference to technological applications. The strong emphasis on fundamentals, however, means that the ideas presented can be applied beyond internal flow to other types of fluid motion. The book equips students and practising engineers with a range of new analytical tools. These tools offer enhanced interpretation and application of both experimental measurements and the computational procedures that characterize modern fluids engineering.

Download or read book Handbook of Wind Energy Aerodynamics written by Bernhard Stoevesandt and published by Springer Nature. This book was released on 2022-08-04 with total page 1495 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook provides both a comprehensive overview and deep insights on the state-of-the-art methods used in wind turbine aerodynamics, as well as their advantages and limits. The focus of this work is specifically on wind turbines, where the aerodynamics are different from that of other fields due to the turbulent wind fields they face and the resultant differences in structural requirements. It gives a complete picture of research in the field, taking into account the different approaches which are applied. This book would be useful to professionals, academics, researchers and students working in the field.

Download or read book Active Flow Control written by Rudibert King and published by Springer Science & Business Media. This book was released on 2007-08-29 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains contributions presented at the Active Flow Control 2006 conference, held September 2006, at the Technische Universität Berlin, Germany. It contains a well balanced combination of theoretical and experimental state-of-the-art results of Active Flow Control. Coverage combines new developments in actuator technology, sensing, robust and optimal open- and closed-loop control and model reduction for control.

Download or read book Control of Fluid Flow written by Petros Koumoutsakos and published by Springer Science & Business Media. This book was released on 2006-05-31 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph presents the state of the art of theory and applications in fluid flow control, assembling contributions by leading experts in the field. The book covers a wide range of recent topics including vortex based control algorithms, incompressible turbulent boundary layers, aerodynamic flow control, control of mixing and reactive flow processes or nonlinear modeling and control of combustion dynamics.

Download or read book Wind Turbines written by Abdel Ghani Aissaoui and published by BoD – Books on Demand. This book was released on 2016-07-27 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Renewable energies constitute excellent solutions to both the increase of energy consumption and environment problems. Among these energies, wind energy is very interesting. Wind energy is the subject of advanced research. In the development of wind turbine, the design of its different structures is very important. It will ensure: the robustness of the system, the energy efficiency, the optimal cost and the high reliability. The use of advanced control technology and new technology products allows bringing the wind energy conversion system in its optimal operating mode. Different strategies of control can be applied on generators, systems relating to blades, etc. in order to extract maximal power from the wind. The goal of this book is to present recent works on design, control and applications in wind energy conversion systems.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1980 with total page 932 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamic Modeling and Flow Control Strategies for Rectangular Jets Application of POD and Wavelet Analysis written by and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research effort has as its objectives: the experimental characterization and low order modeling of the coherent structure dynamics of high Reynolds number rectangular jets of low and moderate aspect ratios via a joint application of the proper orthogonal decomposition (POD) and wavelet analysis techniques. This includes the extraction and characterization of the u, v, and w-component POD eigenfunctions and associated eigenvalues. The rectangular jet dynamics (embodied in the POD temporal coefficients) is obtained by projection of the POD eigenfunctions onto instantaneous realizations of the flow field. This projection is performed via wavelet analysis. Similarly Galerkin projection of a truncated subset of the empirical eigenmodes onto the Navier-Stokes equations is used to develop a low-order dynamical systems model of the rectangular jet flow field. The validity of assumptions associated with the treatment of the truncated modes and their effect on the coherent structure is established by comparing the dynamic behavior resulting from the model ODE's with those from projection of POD modes onto the actual flow. The dynamical system model of the rectangular jet will be utilized for the establishment of rectangular jet flow control strategies. The flow control algorithm will be demonstrated via both the model and laboratory jet flows.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Progress in Astronautics and Aeronautics written by and published by . This book was released on 1963 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: