Download or read book A Higher Order Free Wake Method for Aerodynamic Performance Prediction of Propeller Wing Systems written by Julia Cole and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A new higher-order free-wake (HOFW) method has been developed to enable conceptual design space explorations of propeller-wing systems. The method uses higher order vorticity elements to represent the wings and propeller blades as lifting surfaces. The higher order elements allow for better force resolution and more intrinsically computationally stable wakes than a comparable vortex-lattice method, while retaining the relative ease of geometric representation inherent to such methods. The propeller and wing surfaces and wakes are modeled within the same flow field, thus accounting for mutual interaction without the need for empirical models. The method was shown to be accurate through comparisons with other methods and experimental data. To ensure the method is capable of capturing an unsteady lift response, it was compared with a Kussner function approximation of the change in two-dimensional lift due to a sharp-edged gust. This study showed excellent agreement with an average error in the HOFW lift response of less than 3% from 0 to 10 semi-chords, but required high time and space resolution. The time-accurate lift response of a propeller-wing system as predicted with the HOFW method was then compared with with fully unsteady CFD. These results showed that the HOFW method can identify the peak frequency and general amplitude of the lift oscillations at high resolution. Due to the high resolution requirements, this mode of analysis is not recommended for use in design studies. Time-averaged results found using the HOFW method were compared with experimental propeller, proprotor, and propeller-wing system data, along with two semi-empirical methods. The method matched experimental propeller efficiencies to within 4% for lightly loaded conditions. Increases in lift coefficient due to interaction with a propeller for a series of wings as analyzed with the HOFW method matched the average of those predicted with two semi-empirical methods with an average of 6.5% error for a lightly loaded propeller case. A comparison of HOFW predictions of lift for a more non-conventional propeller-wing system with experimental results over a range of angles of attack showed an average difference of 0.04 in lift coefficient. For this system, predictions in thrust and torque also matched experimental results within 5% over a small angle of attack range (+/- 5 degrees). The method was less successful at predicting the magnitude of drag in comparison with experimental results, but was capable of qualitatively matching trends in drag, both with changes in angle of attack and for variations in design.Finally, two design studies were conducted to show the practical utility of the method: an investigation of the twist distribution on a large civil tiltrotor wing and an investigation into propeller rotation direction and vertical location on a distributed electric propulsion vehicle. The studies showed that the method is capable, fast, accurate, and robust for performance prediction of propeller-wing systems, and thus appropriate for use in design-space exploration.
Download or read book An Analysis for High Speed Propeller nacelle Aerodynamic Performance Prediction Volume 1 Theory and Application written by and published by . This book was released on 1988 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Analysis for High Speed Propeller nacelle Aerodynamic Performance Prediction User s manual written by and published by . This book was released on 1988 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Analysis for High Speed Propeller nacelle Aerodynamic Performance Prediction written by T. Alan Egolf and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Numerical Prediction of Propeller Performance by Vortex Lattice Method written by Cheung, Richard Shiu Wing and published by . This book was released on 1987 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book AGARD Advisory Report written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development and published by . This book was released on 1983 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA SP written by and published by . This book was released on 1992 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aeronautical Engineering written by and published by . This book was released on 1971 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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)
Download or read book Wind Turbine Aerodynamics and Vorticity Based Methods written by Emmanuel Branlard and published by Springer. This book was released on 2017-04-05 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book introduces the fundamentals of fluid-mechanics, momentum theories, vortex theories and vortex methods necessary for the study of rotors aerodynamics and wind-turbines aerodynamics in particular. Rotor theories are presented in a great level of details at the beginning of the book. These theories include: the blade element theory, the Kutta-Joukowski theory, the momentum theory and the blade element momentum method. A part of the book is dedicated to the description and implementation of vortex methods. The remaining of the book focuses on the study of wind turbine aerodynamics using vortex-theory analyses or vortex-methods. Examples of vortex-theory applications are: optimal rotor design, tip-loss corrections, yaw-models and dynamic inflow models. Historical derivations and recent extensions of the models are presented. The cylindrical vortex model is another example of a simple analytical vortex model presented in this book. This model leads to the development of different BEM models and it is also used to provide the analytical velocity field upstream of a turbine or a wind farm under aligned or yawed conditions. Different applications of numerical vortex methods are presented. Numerical methods are used for instance to investigate the influence of a wind turbine on the incoming turbulence. Sheared inflows and aero-elastic simulations are investigated using vortex methods for the first time. Many analytical flows are derived in details: vortex rings, vortex cylinders, Hill's vortex, vortex blobs etc. They are used throughout the book to devise simple rotor models or to validate the implementation of numerical methods. Several Matlab programs are provided to ease some of the most complex implementations.
Download or read book Aeronautical Engineering A Cumulative Index to a Continuing Bibliography supplement 261 written by and published by . This book was released on 1991 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards written by and published by . This book was released on 1998 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theses on any subject submitted by the academic libraries in the UK and Ireland.
Download or read book A Computational and Experimental Study of Nonlinear Aspects of Induced Drag written by Stephen Charles Smith and published by . This book was released on 1995 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aeronautical Engineering A Cumulative Index to a Continuing Bibliography supplement 235 written by and published by . This book was released on 1989 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rotary Wing Aerodynamics written by W. Z. Stepniewski and published by Courier Corporation. This book was released on 2013-04-22 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt: DIVClear, concise text covers aerodynamic phenomena of the rotor and offers guidelines for helicopter performance evaluation. Originally prepared for NASA. Prefaces. New Indexes. 10 black-and-white photos. 537 figures. /div
Download or read book An Improved Panel Method for the Prediction of Performance of Ducted Propellers written by Hongyang Fan and published by . This book was released on 2015 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: An improved perturbation potential based lower order panel method is applied to the three dimensional problems of flow around ducts and ducted propellers. One significant development of this method is the application of full wake alignment scheme in which the trailing vortex wake sheets of the blades are aligned with the local flow velocity by also considering the effects of duct and duct wake. A process of repaneling the duct is simultaneously introduced to improve the accuracy of evaluation of the method. The results from the improved wake model are compared with those from a simplified wake alignment scheme (PSF-2 type scheme). At the same time, full-blown RANS simulations of the three dimensional problem are conducted. The forces, i.e. thrust and torque on the propeller predicted by the present panel method under the improved wake alignment model show good agreement both with experimental measurements, a hybrid method developed by the Ocean Engineering Group of UT Austin, and the full blown RANS simulations. Moreover, detailed pressure distribution on the blades and duct are compared among the various methods. The interactive method which couples the lower order panel method with a two dimensional boundary layer solver through a wall transpiration model is also introduced. An assumption of two dimensional flow is made on the individual stations of a three dimensional geometries and the coupling is applied in a stripwise manner by including the interaction effects from other strips. The interactive method is then validated through the cases of bare ducts and ducted propellers. An important improvement is also made on the extension scheme for hydrofoils and propeller blades with blunt trailing edge. A more physical criterion has been established for determining the location of cut planes or the starting points of the extension. The extension scheme is applied to both axisymmetric problems and fully three dimensional problems. Correlations of results with experimental measurements and RANS simulations are presented.
