Download or read book On Blockage Corrections for Two dimensional Wind Tunnel Tests Using the Wall pressure Signature Method written by and published by . This book was released on 1986 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Blockage Correction in Three dimensional Wind Tunnel Testing Based on the Wall Signature Method written by N. Ulbrich and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wind Tunnel Wall Correction written by B. F. R. Ewald and published by . This book was released on 1998 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report was compiled by an international team of wind tunnel wall correction experts. It presents the present state of the art in wind tunnel wall corrections with a special emphasis given to the description of modern wall correction methods based on Computational Fluid Dynamics. This AGARDograph was planned by the AGARD Fluid Dynamics Panel to be a modern sequel of the successful AGARDograph 109 "Subsonic Wind Tunnel Wall Corrections", which was published in 1966. AGARDogaph 109 is still valid and continues to be used to provide wall corrections in many wind tunnels. Nevertheless, in the thirty two years since the publication of AGARDograph 109, much work has been done on the subject, and the influence of the new tool of numerical fluid dynamics was so strong, that a sequel to AGARDograph 109 was considered to be necessary.

Download or read book Study Implementation and Validation of a Wall Pressure signature Blockage Correction Method for the Wind Tunnel of the ESEIAAT Aerospace Laboratory written by Francisco Javier Faus Dexeus and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this study is the development, implementation and validation of a blockage correction method based on wall pressure signatures. The work involves the design and construction of the required wind tunnel instrumentation and models, as well as the implementation of a computer program to process the wind tunnel data. The program is able to correct dynamic pressure and drag measurements, even for lifting models. In this work, the wall pressure signature is measured in a manual manner by means of a multi-tube manometer which has been designed and built for this purpose. Validation experiments have been also designed and performed using cylinders. A brief uncertainty study of the results is also presented. The program has been developed using MATLAB software. It is based on the iterative version of the wall pressure signature method originally developed by Hackett et al. The program is capable of obtaining a reconstruction of the wall pressure distribution along the wind tunnel walls. From this reconstruction, the required corrections for the dynamic pressure inside the tunnel, the measured aerodynamic resistance and the drag coefficient are obtained. The developed program has been validated experimentally. Experiments on cylinders of different diameter have been carried out to observe the change in corrections for different blockage ratios (relation between model frontal area and tunnel cross-sectional area). Velocity in each experiment has been adjusted in order to maintain a constant Reynolds number between different diameter cylinders. An uncertainty analysis of the results has been performed through the Monte Carlo method to obtain an approximate error for the corrections. The results obtained have been consistent for blockage ratios below 15% and coherent with the descriptions from Hackett. However, the measurements present some discrepancy with published data in the literature. For example, experimental force measures (before correction) obtained have been higher than predicted by other experiments (specially for low blockages). This can be due to some bias in the measurements (produced by misalignment) or simply due to the uncertainty observed in the experiment. Results of the uncertainty analysis have shown that the errors in drag coefficient are considerable for the magnitude of forces measured in the experiment, but reduce significantly as the measured force increases. It has also been observed that a large part of the uncertainty in the results is due to the uncertainty in the measurements of aerodynamic drag.

Download or read book Rectangular wind tunnel Blocking Corrections Using the Velocity ratio Method written by Rudolph W. Hensel and published by . This book was released on 1951 with total page 708 pages. Available in PDF, EPUB and Kindle. Book excerpt: Calculations of the ratios of the velocity increments at test bodies to those at the tunnel walls caused by the solid blocking of these bodies within the walls of a closed rectangular wind tunnel are presented. The boides treated include two-dimensional airfoils; small bodies of revolution; straight, untapered, finite-span wings of varying span; and swept, untapered, finite-span wings of varying span. It is shown that, after wake blocking effects have been removed , the present method furnishes semiempirical blocking corrections for most wind-tunnel models and their components. The test section proportions of the Southern California Cooperative Wind Tunnel at CIT (ratio of height to width equal to 1/square root of 2) are used in the calculations.

Download or read book Wall Interference in Wind Tunnels with Slotted and Porous Boundaries at Subsonic Speeds written by Barrett Stone Baldwin and published by . This book was released on 1953 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Linearized compressible-flow analysis is applied to the study of wind-tunnel-wall interference for subsonic flow in either two-dimensional or circular test sections having slotted or porous walls. Expressions are developed for evaluating blockage and lift interference.

Download or read book Study of the Integration of Wind Tunnel and Computational Methods for Aerodynamic Configurations written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-11-12 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was conducted to determine the effectiveness of using a low-order panel code to estimate wind tunnel wall corrections. The corrections were found by two computations. The first computation included the test model and the surrounding wind tunnel walls, while in the second computation the wind tunnel walls were removed. The difference between the force and moment coefficients obtained by comparing these two cases allowed the determination of the wall corrections. The technique was verified by matching the test-section, wall-pressure signature from a wind tunnel test with the signature predicted by the panel code. To prove the viability of the technique, two cases were considered. The first was a two-dimensional high-lift wing with a flap that was tested in the 7- by 10-foot wind tunnel at NASA Ames Research Center. The second was a 1/32-scale model of the F/A-18 aircraft which was tested in the low-speed wind tunnel at San Diego State University. The panel code used was PMARC (Panel Method Ames Research Center). Results of this study indicate that the proposed wind tunnel wall correction method is comparable to other methods and that it also inherently includes the corrections due to model blockage and wing lift. Browne, Lindsey E. and Ashby, Dale L. Ames Research Center...

Download or read book Wind Tunnel Wall Interference January 1980 May 1988 written by Marie H. Tuttle and published by . This book was released on 1988 with total page 96 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 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Two dimensional Wind Tunnel Wall Interference written by M. Mokry and published by . This book was released on 1983 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: A description and analysis is presented of the more important developments during the past decade in the understanding of the wall interference problem associated with two-dimensional wind tunnel testing at subsonic and transonic speeds. Discussed are: wall boundary conditions; asymptotic analysis of wall interference; classical and extended wall interference theories; wall interference corrections from boundary measurements; integral equation formulation of subcritical wall interference; and effects of side wall boundary layer on two-dimensional tests. Unsteady wall interference at subsonic flow conditions is reviewed. Recent advances in the adaptive wall technique, which actively reduces or eliminates wall interference, are also described. (Author).

Download or read book Research on Adaptive Wall Wind Tunnels written by Robert J. Vidal and published by . This book was released on 1978 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research was to investigate the utility of the Calspan self-correcting wind tunnel for minimizing or eliminating wall interference effects in two-dimensional transonic flows when shock waves from the test model extend to the tunnel walls. This report summarizes the experimental research performed with two-dimensional airfoils in the Calspan self-correcting wind tunnel and the theoretical research accomplished in support of the experiments. The experiments were performed with airfoil models having 4% and 6% solid blockage. The initial experiments with the 6%-blockage model were devoted to determining a practical mode of operation when shock waves from the model extend to the wall. The most practical model is to use wall control to obtain the desired distribution of longitudinal velocity components for subcritical walls. The Mach number is then increased and the wall control is readjusted, sequentially, until the desired test condition is achieved. At the high Mach numbers of interest, however, the available wall control was limited locally, and tunnel system changes were required. A method is reported for analyzing self-correcting wind tunnels with porous walls.

Download or read book NASA Technical Memorandum written by and published by . This book was released on 1986 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Low Speed Wind Tunnel Testing written by Jewel B. Barlow and published by John Wiley & Sons. This book was released on 1999-02-22 with total page 738 pages. Available in PDF, EPUB and Kindle. Book excerpt: A brand-new edition of the classic guide on low-speed wind tunnel testing While great advances in theoretical and computational methods have been made in recent years, low-speed wind tunnel testing remains essential for obtaining the full range of data needed to guide detailed design decisions for many practical engineering problems. This long-awaited Third Edition of William H. Rae, Jr.'s landmark reference brings together essential information on all aspects of low-speed wind tunnel design, analysis, testing, and instrumentation in one easy-to-use resource. Written by authors who are among the most respected wind tunnel engineers in the world, this edition has been updated to address current topics and applications, and includes coverage of digital electronics, new instrumentation, video and photographic methods, pressure-sensitive paint, and liquid crystal-based measurement methods. The book is organized for quick access to topics of interest, and examines basic test techniques and objectives of modeling and testing aircraft designs in low-speed wind tunnels, as well as applications to fluid motion analysis, automobiles, marine vessels, buildings, bridges, and other structures subject to wind loading. Supplemented with real-world examples throughout, Low-Speed Wind Tunnel Testing, Third Edition is an indispensable resource for aerospace engineering students and professionals, engineers and researchers in the automotive industries, wind tunnel designers, architects, and others who need to get the most from low-speed wind tunnel technology and experiments in their work.

Download or read book Determination of Wind Tunnel Constraint Effects by a Unified Pressure Signature Method Part 1 Applications to Winged Configurations written by and published by . This book was released on 1981 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wind Tunnel Wall Interference January 1980 May 1988 A Selected Annotated Bibliography written by Marie H. Tuttle and published by . This book was released on 1988 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Real Time Wall Interference Correction System of the NASA Ames 12 Foot Pressure Wind Tunnel written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-04 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: An improved version of the Wall Signature Method was developed to compute wall interference effects in three-dimensional subsonic wind tunnel testing of aircraft models in real-time. The method may be applied to a full-span or a semispan model. A simplified singularity representation of the aircraft model is used. Fuselage, support system, propulsion simulator, and separation wake volume blockage effects are represented by point sources and sinks. Lifting effects are represented by semi-infinite line doublets. The singularity representation of the test article is combined with the measurement of wind tunnel test reference conditions, wall pressure, lift force, thrust force, pitching moment, rolling moment, and pre-computed solutions of the subsonic potential equation to determine first order wall interference corrections. Second order wall interference corrections for pitching and rolling moment coefficient are also determined. A new procedure is presented that estimates a rolling moment coefficient correction for wings with non-symmetric lift distribution. Experimental data obtained during the calibration of the Ames Bipod model support system and during tests of two semispan models mounted on an image plane in the NASA Ames 12 ft. Pressure Wind Tunnel are used to demonstrate the application of the wall interference correction method. Ulbrich, Norbert Ames Research Center NASA/CR-1998-208537, A-98-11989, NAS 1.26:208537 NAS2-13605...

Download or read book Aerodynamic Characteristics of Two dimensional Wing Configurations at Angles of Attack Near 90 Deg written by and published by . This book was released on 1986 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind tunnel tests were conducted to determine the drag og two-dimensional wing sections operating in a near-vertical flow condition. Various leading-and trailing-edge configurations, including plain flaps of 25, 30, and 35% chord were tested at angles of attack from-75 to -105deg. Reynolds numbers examined ranged from approximately 0.6 to 1.4 million. The data were obtained using a wind tunnel force and moment balance system and arrays of chordwise pressure orifices. The results showed that significant reductions in drag, beyond what would be expected by virtue of the decreased frontal area, were obtainable with geometries that delayed flow separation. Rapid changes in drag with angle of attack were noted for many configurations. The results, however, were fairly insensitive to Reynolds number variations. Drag values computed from the pressure data generally agreed with the force data within 2%. Keywords: Download; Two-dimension wing; Leading edge; trailing edge; Wing flap; Wing slots; Wing slats; Wing spoiler.