Download or read book Determination of the Mass Flow Through Parachute Canopies in Subsonic and Supersonic Flow written by R. J. Niccum and published by . This book was released on with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The success of any parachute system is measured by its performance during the opening sequence and its performance during steady state operation. Earlier presentations in this course have shown that the parachute opening time and opening force are important dynamic parameters which may be used in determining a parachute's desirability for certain applications. Similarly, the steady state aerodynamics such as tangent force coefficient, normal force coefficient, and moment derivative with respect to angle of attack are among the parameters employed for gaging a parachute's steady state worthiness. The purpose of this presentation is to bring to your attention still another parameter that is useful in the design and evaluation of the performance characteristics of parachute systems, namely, the mass flow through a canopy both during its inflation and its steady descent.
Download or read book Experimental Determination of the Subsonic Mass Flow Through Several Ribbon Type Parachute Canopies During Inflation and at Steady State Conditions written by Kenneth B. Buchanan and published by . This book was released on 1968 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of studies to determine the mass flow through circular flat ribbon canopies of several geometric porosities at steady flow conditions and during inflation and through 17% and 27% porous Hemisflo canopies during inflation are presented. Pressure distributions which were established as a necessary part of the study are also included. (Author).
Download or read book Flow Characteristics of Rigid Ribbon Parachute Canopies in Supersonic Flow written by H. G. Heinrich and published by . This book was released on 1965 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: An inlet diffuser model was used in freestream and wake flows to establish the relationship between shock wave standoff distance and mass flow through a cavity. The results of these experiments were used to devise a method to calculate shock wave stanoff distances as a function of the mass flow through the cavity. By means of further experiments, it was shown that this method is useful for carrying out similar calculations for porous parachutes in supersonic flow. The interaction between suspension line boundary layers and the bow shock of porous parachute canopies, and its effect upon the pressure distribution and the pressure drag coefficient, has been studied. Pressure drag coefficients depending on the number of suspension lines were established. (Author).
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.
Download or read book Experimental Determination of Transonic and Supersonic Pressure Distribution and Mass Flow Accommodation for Ribbon Parachutes During Inflation Vol I the 27 Geometric Porosity Hemisflo Ribbon Parachute written by Ronald J. Niccum and published by . This book was released on 1965 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 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. The wake of the ogive forebody with respect to pressure is analyzed. (Author).
Download or read book Experimental Determination of Transonic and Supersonic Pressure Distribution and Mass Flow Accommodation for Ribbon Parachutes During Inflation Volume Ii the 17 Geometric Porosity Hemisflo Ribbon Parachute and Circular Flat Ribbon Parachutes with Various Geometric Porosities written by Ronald J. Niccum and published by . This book was released on 1967 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results are presented in this report of an experimental study to determine the air flow through several fully open circular flat ribbon canopies of various geometric porosities and a 17% geometric porosity Hemisflo canopy during its inflation. The measured mass flows are correlated with inviscid flow as a measure of the canopy's accommodation of the air mass available at the mouth inlet under specific operation conditions. In conjunction with the actual measurements of mass flow, the pressure distributions on the internal and external canopy surfaces were determined. These measurements were made on models with suspension lines as well as on models without suspension lines so that suitable estimates of suspension line effects could be made. Measurements were made at Mach 0.8, 1.2, and 3.0. In addition, several tests were conducted in the wake of an ogive cylinder located at two upstream positions. (Author).
Download or read book Notes on the Cause of Parachute Critical Velocity written by William P. Ludtke and published by . This book was released on 1991 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report discusses how the critical velocity of parachutes depends upon the rate of outflow through the canopy surface and the rate of inflow through the canopy mouth. The analysis indicated that the mass flow rate ratio, M', is demonstrated to be the theoretical key to the critical velocity of parachutes. The effects of M' and altitude on inflation reference time, parachute stability, drag coefficient, and inflation rate are also discussed.
Download or read book Computational Fluid Dynamic Studies of a Solid and Ribbon 12 gore Parachute Canopy in Subsonic and Supersonic Flow written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aerodynamic Characteristics of the Supersonic Guide Surface and the Spiked Ribbon Parachutes written by Helmut G. Heinrich and published by . This book was released on 1965 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: The location of shock waves, the pressure distribution and the mass flow, which are significant for the functioning of a parachute in supersonic flow, are discussed and some advantageous conditions are postulated. Wind tunnel studies are described in which the validity of the assumptions has been checked by means of models of a modified guide surface canopy combined with a shock producing cone. A configuration was found according to which 4 inch textile models function satisfactorily up to Mach numbers of 4.5. The results of further supersonic wind tunnel tests are shown in which a 4 ft supersonic guide surface parachute, built in accordance with the established aerodynamic parameters, functioned satisfactorily. This parachute collapsed due to structural weakness at a Mach number of 2.8 after being exposed to supersonic flow for approximately 90 minutes. The concept of the wake producing cone in conjunction with ribbon parachute canopies was also tried, but no satisfactory configuration was found. (Author).
Download or read book Measurements of Aerodynamic Forces on Unsteadily Moving Bluff Parachute Canopies written by D. J. Cockrell and published by . This book was released on 1987 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Equations which describe the unsteady motion of bluff bodies through fluids contain certain components, termed added mass coefficients, which can be determined only by experiment. From the solutions to such equations the ways in which the shapes of parachute canopies influence the frequency of their oscillatory motion in pitch and their corresponding damping rates are required. Although a full-scale parachute canopy descends through air, oscillating in pitch as it does so, experiments necessary to determine these added mass coefficients have been performed underwater, using for this purpose a large ship tank from the towing carriage of which the model parachute canopies were suspended. These experiments showed that the added mass coefficients for bluff parachute canopies differed appreciably from their corresponding potential flow values. The latter were obtained from the analysis of inviscid fluid flow round regular shapes which were representative of those parachute canopies. The significance for the prediction of the parachute's dynamic behavior in pitch of these differences is outlined.
Download or read book Pressure Distribution Measurements of Conventional Ribbon Parachutes in Supersonic Flow written by Eugene L. Haak and published by . This book was released on 1962 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conventionally shaped Ribbon parachutes do not function satisfactorily as aerodynamic decelerators in supersonic flow. Particularly objectionable is their unstable behavior. In order to determine the cause of this structural and dynamic instability, a series of pressure distribution measurements were made on ribbon parachutes at Mach numbers of 0.8, 1.2, 3.0, and 4.5. This report presents the results of measurements and attempts to indicate the effect of suspension lines and forebodies on the pressure distribution of the parachute canopy.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 1460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Wind Tunnel Investigation of Conventional Types of Parachute Canopies in Supersonic Flow written by R. A. MEYER and published by . This book was released on 1958 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aerodynamic Principles of the Supersonic Guide Surface Parachute written by Helmut G. Heinrich and published by . This book was released on 1964* with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The location of shock waves, the pressure distribution and the mass flow, which are significant for the functioning of a parachute in supersonic flow, are being discussed and some advantageous conditions are postulated. Wind tunnel studies are described in which the validity of the assumptions has been checked by means of models of a modified guide surface canopy combined with a shock producing cone. A configuration was found according to which 10-centimeter textile models function satisfactorily up to Mach numbers of 4.5. The results of further supersonic wind tunnel tests are shown in which a 1.2 meter supersonic guide surface parachute, built in accordance with the established aerodynamic parameters, functioned satisfactorily. This parachute collapsed due to structural weakness at a Mach number of 2.8 after being exposed to supersonic flow for approximately 90 minutes.
Download or read book Analysis of an Inflating Subsonic Reefed Parachute with Experimental Mass Flow Study written by William K. Lockman and published by . This book was released on 1963 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Drag and Stability Characteristics of a Variety of Reefed and Unreefed Parachute Configurations at Mach 1 80 with an Empirical Correlation for Supersonic Mach Numbers written by Lana M. Couch and published by . This book was released on 1975 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation was conducted at Mach 1.80 in the Langley 4-foot supersonic pressure tunnel to determine the effects of variation in reefing ratio and geometric porosity on the drag and stability characteristics of four basic canopy types deployed in the wake of a cone-cylinder forebody. The basic designs included cross, hemisflo, disk-gap-band, and extended-skirt canopies; however, modular cross and standard flat canopies and a ballute were also investigated. An empirical correlation was determined which provides a fair estimation of the drag coefficients in transonic and supersonic flow for parachutes of specific geometric porosity and reefing ratio.
Download or read book Study of Parachute Forces and Canopy Pressure Distribution Measured in a Subsonic Wind Tunnel Under Infinite Mass Conditions written by Helmut G. Heinrich and published by . This book was released on 1972 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the purpose of parachute canopy stress analysis during the period of inflation, the pressure distribution measured on a ring-slot parachute model is related to the instantaneous parachute force. The correlation of pressure and force data is based on test results established at the Deutsche Forschungsanstalt fuer Luft-und Raumfahrt (DFLR), Braunschweig, Germany. The final pressure-force-time relationship incorporate individual as well as averaged test data. A fair agreement could be shown between measured forces and those obtained from numerical integration of differential pressure over the canopy surface.
