Download or read book Investigation of the Flow Field During the Inflation of Clustered Parachutes written by R. J. Niccum and published by . This book was released on 1966 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clustered parachutes during the period of inflation were simulated by elliptical cylinders in potential flow and so-called O'Hara shape parachutes in water flow and wind tunnel experiments. The results are presented in the form of streamline and pressure distribution plots around the respective bodies. Results show that when geometric symmetry is disturbed, the flow field becomes unsymmetrical and strong attractive or repulsive forces are developed. This allows a variety of inflation modes to occur and, hence, poor cluster opening performance.
Download or read book Technical Abstract Bulletin written by Defense Documentation Center (U.S.) and published by . This book was released on 1967 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Parachute Inflation Process Wind tunnel Study written by Edwin Pounder and published by . This book was released on 1956 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents results of an experimental study of the parachute inflation process. The investigation was carried out in a low speed wind tunnel using small cloth models, and an analysis is presented which gives a basis for extrapolation of the data recorded to any reasonably low Mach number case. The drag of the parachutes and the shapes of the canopies during the inflation process are studied in considerable detail, and some qualitative studies of the flow fields are conducted. The principle variables studied are parachute type, velocity (dynamic pressure), and canopy porosity. The theoretical analysis develops a procedure by which full scale characteristics can be predicted from wind tunnel data, and several examples are computed to illustrate the technique.
Download or read book Computational Fluid Dynamics Modeling of Parachute Clusters written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A computational tool that models the terminal descent characteristics of a single or a cluster of parachutes is a technology that is needed by parachute designers and engineers. As part of a technology program annex (TPA), a joint effort between the U.S. Army Natick Research, Development, and Engineering Center (RRDEC) and the U.S. Army Research Laboratory (ARL) to develop this computational tool is now under way. As a first effort, attempts are being made to analyze both two-dimensional (2- D) and three-dimensional (3-D) flow fields around a parachute using a coupling procedure in which the fluid dynamics are coupled to 2-D and 3-D structural dynamic (SD) codes. This effort uses computational fluid dynamic (CFD) codes to calculate a pressure field, which is then used as an input load for the SD code. Specifically, this report presents the methods and results of the flow field plus the structural characteristics of a single axisymmetric parachute and a 3-D gore configuration for the terminal descent velocity. Computed results have been obtained using the payload weight and unstretched constructed geometry of the canopies as input. Significant progress has been made in determining the terminal descent flow field along with the terminal shape of the parachute. A discussion of the fluid and structural dynamics codes, coupling procedure, and the associated technical difficulties is presented. Examples of the codes' current capabilities are shown.
Download or read book Recovery System Design Guide written by E. G. Ewing and published by . This book was released on 1979 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt: This document serves as the third revision of the USAF Parachute Handbook which was first published in 1951. The data and information represent the current state of the art relative to recovery system design and development. The initial chapters describe representative recovery applications, components, subsystems, material, manufacture and testing. The final chapters provide empirical data and analytical methods useful for predicting performance and presenting a definitive design of selected components into a reliable recovery system.
Download or read book The Internal and External Flow Field Associated with Parachutes During Inflation written by Gregory C. De Santis and published by . This book was released on 1970 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: A hot-wire anemometer was used to obtain data on the flow field associated with an inflating parachute. Seven models simulating various stages of inflation of the C-9 parachute were fabricated and tested in a specially constructed test section where the temperature could be held uniform. Using this method, it was possible to accurately measure the internal and external flow surrounding the canopy. Some possible applications of the data to full-scale parachute systems are presented. (Author).
Download or read book Computational Fluid Dynamics Modeling of Parachute Clusters written by and published by . This book was released on 1997 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: A computational tool that models the terminal descent characteristics of a single or a cluster of parachutes is a technology that is needed by parachute designers and engineers. As part of a technology program annex (TPA), a joint effort between the U.S. Army Natick Research, Development, and Engineering Center (RRDEC) and the U.S. Army Research Laboratory (ARL) to develop this computational tool is now under way. As a first effort, attempts are being made to analyze both two-dimensional (2- D) and three-dimensional (3-D) flow fields around a parachute using a coupling procedure in which the fluid dynamics are coupled to 2-D and 3-D structural dynamic (SD) codes. This effort uses computational fluid dynamic (CFD) codes to calculate a pressure field, which is then used as an input load for the SD code. Specifically, this report presents the methods and results of the flow field plus the structural characteristics of a single axisymmetric parachute and a 3-D gore configuration for the terminal descent velocity. Computed results have been obtained using the payload weight and unstretched constructed geometry of the canopies as input. Significant progress has been made in determining the terminal descent flow field along with the terminal shape of the parachute. A discussion of the fluid and structural dynamics codes, coupling procedure, and the associated technical difficulties is presented. Examples of the codes' current capabilities are shown.
Download or read book Flow Field Visualization in the Wake of a Ribbon Parachute written by William L. Garrard and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation was conducted to determine the flow field in the wake of a flexible ribbon parachute model. A nylon ribbon parachute model with a geometric porosity of 20 percent was mounted in an open section of a horizontal return wind tunnel at an angle of attack of approximately zero degrees. To define the flow field, tufts were introduced into the wake of the parachute by means of a steel rod fastened to a sting [sic] that ran down the centerline of the parachute. Two photographs were taken simultaneously to record the pattern of the flow field at that given instant of time. These photographs could then be used in conjunction with high-speed movies already produced to determine the direction of the flow in the wake of the parachute. The results of this study seem to indicate that the photographs taken can help aid in determining the flow direction.
Download or read book Parachute Recovery Systems written by Theo W. Knacke and published by . This book was released on 1992 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this manual is to provide recovery system engineers in government and industry with tools to evaluate, analyze, select, and design parachute recovery systems. These systems range from simple, one-parachute assemblies to multiple-parachute systems, and may include equipment for impact attenuation, flotation, location, retrieval, and disposition. All system aspects are discussed, including the need for parachute recovery, the selection of the most suitable recovery system concept, concept analysis, parachute performance, force and stress analysis, material selection, parachute assembly and component design, and manufacturing. Experienced recovery system engineers will find this publication useful as a technical reference book; recent college graduates will find it useful as a textbook for learning about parachutes and parachute recovery systems; and technicians with extensive practical experience will find it useful as an engineering textbook that includes a chapter on parachute- related aerodynamics. In this manual, emphasis is placed on aiding government employees in evaluating and supervising the design and application of parachute systems. The parachute recovery system uses aerodynamic drag to decelerate people and equipment moving in air from a higher velocity to a lower velocity and to a safe landing. This lower velocity is known as rate of descent, landing velocity, or impact velocity, and is determined by the following requirements: (1) landing personnel uninjured and ready for action, (2) landing equipment and air vehicles undamaged and ready for use or refurbishment, and (3) impacting ordnance at a preselected angle and velocity.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1997 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Study of the Performance of Clustered Parachutes in a Low speed Wind Tunnel written by B. Kurt Baca and published by . This book was released on 1985 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent interest in clusters of parachutes prompted a review of cluster drag data and inflation characteristics. This examination indicated that very little well-documented data exist that are suitable for broad applications. A low-speed wind-tunnel test program was devised to measure the effects of variations in four important parameters on the terminal drag and stability of clusters of parachutes. The parameters studied were canopy number, canopy type, riser length, and reefing. Efforts were made to account for effects stemming from the experiment's design, especially wind-tunnel blockage. Many of the results of the wind-tunnel tests were validated by a series of drop tests. Terminal drag and stability data are presented here along with proposed explanations for observed phenomena.
Download or read book Model Studies of Inflation Uniformity of Clustered Parachutes written by H. G. Heinrich and published by . This book was released on 1971 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: The uniformity of the opening characteristics of free flying model parachute clusters with and without inflation aids was investigated. Models of 5 ft. nominal diameter with low stiffness index were fired from a compressed air catapult and the parachute forces versus time were recorded. The model tests showed that in clusters of three parachutes the configurations of the standard parachute with riser extension and the standard parachute with an internal canopy without riser extension had the best performance characteristics.
Download or read book Helium Bubble Survey of a Parachute Opening Flowfield written by Paul C. Klimas and published by . This book was released on 1972 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: A velocity survey of the flow field surrounding an 18 inch nominal diameter flat circular parachute model was made using the helium bubble technique. Due to asymmetrical model behavior arising from optical limitations, only two points in the filling cycle were examined. The point at which the canopy first reaches full open (instant at which inflation is comnplete) and at a time late in the cycle when steady state flow conditions are reached. Bubble streaks were photographed by two synchronized, orthogonally mounted still cameras, and the particle velocities were calculated using the measured lengths of the images and the camera exposure times. Although the canopy geometries at the two points considered were quite similar, their surrounding flow fields were not. At the instant of full inflation, both the axial and radial velocities reached much higher values than in the steady state operation and were confined to a region much closer to the canopy. Additionally, the turbulent wake area near the vent was roughly only 40% as large as the steady state counterpart, and it has associated with it an average negative velocity equal to approximately one half the free-stream value.
Download or read book AIAA Student Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 1969 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analytical Investigation of Parachute Inflation Time written by Richard Charles Cutshall and published by . This book was released on 1959 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Note written by and published by . This book was released on 1973 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Determination of Transonic and Supersonic Pressure Distribution and Mass Flow Accommodation for the Hemisflo Ribbon Parachute During Inflation written by Ronald J. Niccum and published by . This book was released on 1965 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the results of an experimental study to qualitatively determine the air flow through a Hemisflo ribbon parachute during the inflation process. These measured mass flows are analyzed relative to free stream velocity and density ratio. The results are presented as ratios of measured to inviscid flow through the canopy inlet area, thus giving a measure of the canopy's ability to accommodate the air mass entering the parachute mouth. Related to the mass flow studies, was the determination of pressure distributions on the internal and external canopy surfaces. Measurements were made at Mach 0.8, 1.2, and 3.0. In addition, several tests were conducted using an ogive forebody at two upstream locations.
