| Approximations of Surface Roughness Effects for Airblast Calculations |
01 NOV 85 |
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| Authors:
T. H. Pierce; S-CUBED LA JOLLA CA
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 | A brief description of roughness effects on a boundary layer is given. The effects of the amount of areal roughness coverage on the law of the wall are summarized. The concept of hydrodynamically equivalent rough surfaces is discussed. The issue of non-uniform roughness element sized is addressed. Some comments are offered relative to roughness scaling. Roughness, Jet flow, Boundary layer, Surface shear, Non-ideal airblast, Turbulent boundary layer. (JES) |
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| Fuel-Air Explosive Nuclear Airblast Simulator. Investigation of Secondary Waves |
01 APR 82 |
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| Authors:
T. H. Pierce; M. A. Groethe; S-CUBED LA JOLLA CA
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| The small-scale DNA fuel-air explosives airblast facility (1/4 T nuclear airblast equivalent) was modified to increase pressure and photographic instrumentation. Additional preparations were undertaken to enable tests to be conducted under a variety of conditions thought to be responsible for secondary shock wave formation. A number of experiments were conducted. These indicated that: (1) detonation was marginally initiated in the fuel-air clouds; (2) cloud shape did not greatly influence the ... |
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| Investigation of a Reusable Fuel-Air Explosive Nuclear Airblast Simulator |
01 FEB 1982 |
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| Authors:
T. H. Pierce; R. T. Sedgwick; M. A. Groethe; S-CUBED LA JOLLA CA
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| Development requirements relating to a reusable, one-kiloton level nuclear airblast simulator using fuel-air explosives is being investigated. The simulator concept is that of a large liquid fuel dispenser, comprising a cluster of radially-directed nozzles. An appropriate fuel would be impulsively injected through this nozzle cluster and the hemispherically-shaped fuel-air cloud so formed would then be detonated. During the contract period reported, work progressed in three areas. These are: the design ... |
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| Fuel-Air Explosive Simulation of Far-Field Nuclear Airblasts |
31 DEC 1979 |
244 pages |
| Authors:
T. H. Pierce; R. T. Sedgwick; S-CUBED LA JOLLA CA
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 | Fuel-air explosions (FAE) have been investigated in the context of far-field nuclear airblast simulation. The objective of the investigation is to determine the feasibility of a reusable FAE simulator at the one kiloton level. Two issues have been researched in parallel efforts. These are the mechanisms by which largescale FAE clouds of controlled shape can be reliably and repeatedly formed and detonated, and the quality of nuclear airblast simulation that ... |
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| Tunnel Location by Gas Flow |
15 JAN 79 |
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| Authors:
P. L. Lagus; T. H. Pierce; D. R. Grine; SYSTEMS SCIENCE AND SOFTWARE LA JOLLA CA
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| Defense Advanced Research Agency (DARPA) has funded a program to improve capabilities to detect existing, hidden tunnels. Systems, Science and Software investigated both the seismic and gas flow characteristics of the rocks surrounding a test mine. Gas injection measurements showed communication by both pressure rise and arrival of tracer gas between the two boreholes from the surface on one side of the mine. The initial results made cross-borehole measurements of ... |
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| Mechanism in the Detonation Regime. |
JUN 1974 |
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| Authors:
J. a. Nicholls; T. H. Pierce; L. Dye; R. Fry; K. Kearney; MICHIGAN UNIV ANN ARBOR GAS DYNAMICS LABS
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| A vertical detonation tube was used to study the blast initiated detonation of various liquid fuels (organic nitrates and nitro compounds), including some monopropellants, in a few different oxygen-nitrogen atmospheres. The fuels tested included n-propyl nitrate, nitropropane, nitromethane, and decane. All fuel drops were of the same size and a range of mixture ratios were tested. Attention was given to the influence of diaphragm thickness, ignition point location in the ... |
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| CONDENSATION OF METAL VAPOR IN A SUPERSONIC CARRIER GAS. |
JUN 1969 |
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| Authors:
P. M. Sherman; D. D. McBride; T. Chmielewski; T. H. Pierce; E. Oktay; MICHIGAN UNIV ANN ARBOR DEPT OF AEROSPACE ENGINEERING
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| A study of the condensation of metal vapor in an inert carrier gas was made with primary emphasis on the size of the particles formed and the location of the onset of the condensation. Superheated zinc vapor was generated in a hotshot wind tunnel in a helium carrier gas and expanded in a converging-diverging nozzle. Static pressure measurements were made to determine the location of the onset of condensation. A ... |
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