Download or read book Blast Parametric Study Using a 1 57 Scale Single Driver Model of a Large Blast Simulator written by George A. Coulter and published by . This book was released on 1987 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: A 1:57 scale, single cold air driver model of a large blast simulator was constructed and operated in driver overpressure range of 300-1800 kPa. Recorded overpressures were in a 10-225 kPa range for the given driver pressures. Blast parameters of overpressure, positive impulse, cold gas arrival and drag enhancement, and recompression fan arrival were measured at stations 7-28 diameters along the test section of the simulator model. The cold gas arrival at the test stations was found to enhance the dynamic drag pressure by a factor of two at the 220 kPa input level. Similar, although larger enhancement was predicted by the BRL-Q1D Code simulation. Effects of driver length, volume, and throat baffle ratio for the full-size simulator operating range are presented in tabular and graphical form. Because of the large cold gas dynamics drag enhancement at test section pressures above 100 kPa, it is recommended that a hot gas driver be used for the full-size simulator. Due to the side-on overpressure positive duration decrease caused by arrival of the throat nozzle recompression fan, a station at 20 test section diameters should be used for the full-scale simulator. (Author).
Download or read book Performance Predictions for the Large Blast Thermal Simulator Based on Experimental and Computational Results written by and published by . This book was released on 1991 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: A computational study was performed with the BRL-Q1D code to determine the expected performance characteristics fo the proposed U.S. Large Blast/Thermal Simulator (LB/TS). This computational study complements an earlier experimental parametric study which was performed in the 25.4-cm shock tube located at the BRL. For the experiments, the BRL 25.4-cm shock tube was configured as a 1:57 scale, axisymmetric, single-driver model of the LB/TS. This report documents two computational parametric studies which were performed to determine the range of nuclear blast simulations available with the current LB/ TS design. The first parametric study s a comparison with existing experimental data to validate the computational model and to determine the limits of its accuracy. The second parametric study used the validated computational model to predict the operating range of the LB/TS design.
Download or read book Technical Reports Awareness Circular TRAC written by and published by . This book was released on 1987-11 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computers in Engineering written by and published by . This book was released on 1993 with total page 808 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computers in Engineering 1993 written by Fatih Kinoglu and published by . This book was released on 1993 with total page 798 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Studies for 1 57 Scale Large Blast Simulator LBS Configurations with the BLAST2D Code written by and published by . This book was released on 1990 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the continuing research efforts of the Blast Dynamics Branch at the U.S. Army Ballistic Research Laboratory (BRL) is to simulate the flow that results from nuclear explosions and to test the nuclear survivability of military equipment. When atmospheric nuclear blast tests were banned, chemical explosive tests were designed and conducted to simulate the blast and thermal pulses produced by real nuclear explosions. These full-scale tests provided data for analysis of nuclear survivability to tactical Army equipment. However, the logistics and expense of full-scale chemical explosive tests meant that an average of only one test could be conducted every two years. A series of computational simulations are performed for comparison to experimental data from a 1/57 -scale Large Blast Simulator (LBS) experimental shock tube. The computations simulate experiments with various high pressure and temperature initial driver gas conditions. In addition to temperature and pressure variations, geometry and numerical accuracy variation are performed and studied. The computations were performed using an axisymmetric, inviscid, time-accurate, finite-volume numerical technique which employs upwind flux differencing with total variation diminishing techniques. Computational results are presented in the form of static and stagnation pressure versus time histories and contour plots. Keywords: Supercomputer simulations, Euler equations, Upwind.
Download or read book Computers in Engineering 1989 Knowledge based systems computer aided engineering design optimization computer simulation of mechanical systems computer graphics robotics specialty process controls and data acquisition systems written by and published by . This book was released on 1989 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1987 with total page 1256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.
Download or read book Performance and Predictions for a Large Blast Simulator Model written by D. M. Hisley and published by . This book was released on 1985 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt: An attempt is made to verify the predictions from a l-D BRL Code against the flow from a complicated, non-straight shock tube configuration; the code then could be utilized for future Large Blast/Thermal Simulator (LB/TS) design and prediction of performance, The shock tube is a 1/37 scale, axisymmetric model following the design for a multi-driver large blast simulator (LBS) located at Centre d'Etude, Gramat, France. It is used to produce shock pressures from 3.1 to 31 psi (21 to 214 kPa) and characteristic decaying wave forms. The BRL code is a quasi-one-dimensional, adiabatic, inviscid, Eulerian computer algorithm. The code is described and some preliminary checks against related configurations are performed. Furthermore, the code uses the experimental tube geometry and run conditions to generate flow data for comparison with the experimental data. Additionally, parameter studies are done-necking down of nozzle throat at the diaphragm station, heating of the driver gas, temperature effect on driver due to pressurizing--to check their influence on the tube behavior. In general, computed blast wave forms as well as levels agree well with experiment except for the highest levels where head losses and real gas effects are more pronounced. With the natural-burst-of-diaphragm operation of tube, diaphragm blockage of the nozzle throat is a problem; temperature effects due to pressurizing of driver are not.
Download or read book Computational Studies of Wave Shaping in a Blast Simulator by Perforated Plates in the Driver written by Dixie M. Hisley and published by . This book was released on 1987 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational simulation of shock tubes with baffles on their driver sections were performed using the (BRL) Quasi-One-Dimensional (Q1D) computer code. The credibility of the code was established through comparisons with experimental data. A numerical parametric study was performed in which baffle positions and area openings in a computational model of a candidate Large Blast/Thermal Simulator (LB/TS) were manipulated until blast wave forms at weapon yields of interest were obtained. Keywords: Blast wave shaping; Blast simulators; Baffles.
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1991-10 with total page 1502 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vierte Reichsmusiktage der Hitlerjugend written by and published by . This book was released on 1939 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index Keyword A L written by and published by . This book was released on 1987 with total page 1260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index Corporate author written by and published by . This book was released on 1987 with total page 1028 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Blast Effects written by Isabelle Sochet and published by Springer. This book was released on 2017-12-22 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book compiles a variety of experimental data on blast waves. The book begins with an introductory chapter and proceeds to the topic of blast wave phenomenology, with a discussion on Rankine-Hugoniot equations and the Friedlander equation, used to describe the pressure-time history of a blast wave. Additional topics include arrival time measurement, the initiation of detonation by exploding wires, a discussion of TNT equivalency, and small scale experiments. Gaseous and high explosive detonations are covered as well. The topics and experiments covered were chosen based on the comparison of used scale sizes, from small to large. Each characteristic parameter of blast waves is analyzed and expressed versus scaled distance in terms of energy and mass. Finally, the appendix compiles a number of polynomial laws that will prove indispensable for engineers and researchers.
Download or read book Feasibility Study for a Large Blast Simulator written by A. H. Wiedermann and published by . This book was released on 1964 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Simulation of Blast Interaction with the Human Body written by Tyler Haladuick and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In Operations Enduring Freedom and Iraqi Freedom, explosions accounted for 81% of all injuries; this is a higher casualty percentage than in any previous wars. Blast wave overpressure has recently been associated with varying levels of traumatic brain injury in soldiers exposed to blast loading. Presently, the injury mechanism behind primary blast brain injury is not well understood due to the complex interactions between the blast wave and the human body. Despite these limitations in the understanding of head injury thresholds, head kinematics are often used to predict the overall potential for head injury. The purpose of this study was to investigate head kinematics, and predict injury from a range of simulated blast loads at varying standoff distances and differing heights of bursts. The validated Generator of body data multi-body human surrogate model allows for numerical kinematic data simulation in explicit finite element method fluid structure interaction blast modeling. Two finite element methods were investigated to simulate blast interaction with humans, an enhanced blast uncoupled method, and an Arbitrary Lagrangian Eularian fully coupled method. The enhanced blast method defines an air blast function through the application of a blast pressure wave, including ground reflections, based on the explosives relative location to a target; the pressures curves are based on the Convention Weapons databases. LBE model is efficient for parametric numerical studies of blast interaction where the target response is the only necessary result. The ALE model, unlike classical Lagrangian methods, has a fixed finite element mesh that allows material to flow through it; this enables simulation of large deformation problems such as blast in an air medium and its subsequent interaction with structures. The ALE model should be used when research into a specific blast scenario is of interest, since this method is more computationally expensive. The ALE method can evaluate a blast scenario in more detail including: explosive detonation, blast wave development and propagation, near-field fireball effects, blast wave reflection, as well as 3D blast wave interaction, reflection and refraction with a target. Both approaches were validated against experimental blast tests performed by Defense Research and Development Valcartier and ConWep databases for peak pressure, arrival time, impulse, and curve shape. The models were in good agreement with one another and follow the experimental data trend showing an exponential reduction in peak acceleration with increasing standoff distance until the Mach stem effect reached head height. The Mach stem phenomenon is a shock front formed by the merging of the incident and reflected shock waves; it increases the applied peak pressure and duration of a blast wave thus expanding the potential head injury zone surrounding a raised explosive. The enhanced blast model was in good agreement with experimental data in the near-field, and mid-field; however, overestimated the peak acceleration, and head injury criteria values in the far-field due to an over predicted pressure impulse force. The ALE model also over predicted the response based on the head injury criteria at an increased standoff distance due to smearing of the blast wave over several finite elements leading to an increased duration loading. According to the Abbreviated Injury Scale, the models predicted a maximal level 6 injury for all explosive sizes in the near-field, with a rapid acceleration of the head over approximately 1 ms. There is a drastic exponential reduction in the insult force and potential injury received with increasing standoff distance outside of the near-field region of an explosive charge.
