Download or read book Analysis of Confined Flows Airfoils and Wings at Low Reynolds Numbers written by Araz Panahi and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "This thesis presents a deep analysis of the steady and unsteady viscous flows past airfoils and three-dimensional wings, and of three-dimensional confined flows at low Reynolds numbers. This research work was carried out in several cases studies: (i) steady and unsteady confined viscous flows; (ii) unsteady separations effects on the flow past stationary airfoils; (iii) effect of the ground proximity on the steady and unsteady viscous flows past oscillating and fixed airfoils; (iv) three-dimensional steady flows past wings at low Reynolds numbers. The first part presents an efficient numerical method to solve three-dimensional steady and unsteady flows in a three-dimensional downstream-facing step channel at low Reynolds numbers. A finite-difference formulation and artificial compressibility were used on a stretched staggered grid for the solution of the Navier-Stokes equations, which is second-order accurate in space and time. The results were found to be in good agreement with the available experimental results. For the first time it was confirmed that the difference between the two-dimensional numerical solutions and the experimental results was due to the effect of the lateral walls in the experimental configuration.The second part is the study of the unsteady effects on stationary airfoils due to unsteady flow separations at low Reynolds numbers. This study was performed with an efficient time-accurate numerical method using a pseudo-time relaxation procedure with artificial compressibility and a factored Alternate-Direction Implicit (ADI) scheme for the pseudo-time integration. The method is successfully validated by comparison with the experimental results obtained by Suwa et al. for triangular airfoils at low Reynolds numbers. It was found that the aerodynamic coefficients of lift and drag displayed periodic variations in time due to the unsteady flow separations occurring at low Reynolds numbers on stationary airfoils at relatively small angles of attack.Analysis of the steady and unsteady flows over airfoils in the proximity of the ground was studied in the third part. Various flight evolutions of the micro-air-vehicles take place in the proximity of the ground or a ceiling, which require the aerodynamic solutions in these conditions at low Reynolds numbers. Solutions are presented for the unsteady lift and drag coefficients of several NACA airfoils in the proximity of the ground. A detailed study of the influence of various geometric and flow parameters, such as the angle of attack, airfoil relative thickness, amplitude and frequency of oscillations and Reynolds number, on the flow separations in the proximity of the ground were carried out in this part. This study also presented the analysis of the unsteady flows past stationary airfoils in the proximity of the ground, aiming to determine the influence of the distance to the ground on these unsteady effects which are generated by the unsteady flow separations on the stationary airfoils at low Reynolds numbers. It was found that these unsteady effects appear at lower angles of attack for the airfoils in the proximity of the ground than in free flight.The fourth and final case study is the three-dimensional analysis of the steady viscous flows past rectangular wings with various NACA airfoil sections at low Reynolds numbers. The solutions are obtained using an efficient numerical method to solve the Navier-Stokes equations for incompressible flows. The numerical solutions of the aerodynamic lift and drag coefficients obtained by this method are validated with the experimental results obtained by Sunada et al. for rectangular wings. A parametric study of the influence of various geometric and flow parameters, such as wing thickness, wing airfoil camber, angle of attack and Reynolds number is also presented." --
Download or read book Summary of Low Speed Airfoil Data written by Michael S. Selig and published by Soartech. This book was released on 1995 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of Low Reynolds Number Airfoil Flows written by John A. Ekaterinaris and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low Reynolds Number Aerodynamics written by Thomas J. Mueller and published by Springer. This book was released on 2012-03-01 with total page 451 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current interest in a variety of low Reynolds number applications has focused attention on the design and evaluation of efficient airfoil sections at chord Reynolds numbers from about 100,000 to about 1,000,000. These applications include remotely piloted vehicles (RPVs) at high altitudes, sailplanes, ultra-light man-carrying/man powered aircraft, mini-RPVs at low altitudes and wind turbines/propellers. The purpose of this conference was to bring together those researchers who have been active in areas closely related to this subject. All of the papers presented are research type papers. Main topics are: Airfoil Design and Analysis, Computational Studies, Stability and Transition, Laminar Separation Bubble, Steady and Unsteady Wind Tunnel Experiments and Flight Experiments.
Download or read book Laminar Flow Airfoil Design and Analysis for Low Reynolds Number Applications written by William B. Smith (CAPT, USAF.) and published by . This book was released on 1976 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Study of Unsteady Low reynolds Number Wing Performance written by Ashok Gopalarathnam and published by . This book was released on 2008 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unsteady motions of airfoils at low Reynolds numbers were studied computationally using low-order vortex lattice methods and using two high-order methods: a Reynolds Averaged Navier-Stokes code and an Immersed Boundary method. Results from the low-order methods compared well with experimental and computational results in the literature for small reduced amplitudes and frequencies. The high-order methods were compared with experiments on high intensity pitch and plunging motions at Reynolds numbers of 10,000 and 40,000. The pitch (rotation about the quarter chord) and plunge motions were at reduced frequencies of 3.93 and with kinematically equivalent amplitudes of effective angle of attack at the quarter-chord location. For the plunge cases, agreement between computation and experiment was qualitatively excellent and quantitatively acceptable, but for the pitch cases, the wake structure in the experiment was markedly different from that predicted by both computations, which were however similar among one another. In all cases, Reynolds number effects were found to be negligible. On-going research aims to determine the parameters necessary for pitch-plunge equivalence and also resolve the poor experiment-computation agreement for pitch.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Analysis of the Design of Airfoil Sections for Low Reynolds Numbers written by Stanley Jay Miley and published by . This book was released on 1972 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low Reynolds Number Aerodynamics of Flapped Airfoils at Supersonic Speeds written by James L. Amick and published by . This book was released on 1958 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance of an Airfoil and Three Rectangular Planform Wings at Low Reynolds Numbers written by William G. Bastedo and published by . This book was released on 1984 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Parametric Study of Low Reynolds Number Effects on Two Dimensional Airfoils and Finite Wings written by Behrooz Ahdoot and published by . This book was released on 1991 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance Characteristics of Airfoil Flows at Low Reynolds Numbers written by Kim Young Rae and published by . This book was released on 1995 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of Experimental Data for Cast 10 2 DOA 2 Supercritical Airfoil at Low Reynolds Numbers and Application to High Reynolds Number Flow written by Y. Y. Chan and published by . This book was released on 1989 with total page 33 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 1991 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biomimetics written by Yoseph Bar-Cohen and published by CRC Press. This book was released on 2016-04-19 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mimicking nature - from science fiction to engineering realityHumans have always looked to nature's inventions as a source of inspiration. The observation of flying birds and insects leads to innovations in aeronautics. Collision avoidance sensors mimic the whiskers of rodents. Optimization algorithms are based on survival of the fittest, the seed-
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1948 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Data Digest written by and published by . This book was released on 1952 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt:
