Accession Number : ADB118436

Title :   Non-Ideal Airblast Phenomenology Program. Volume 2. Thermal Precursor Analysis, Moist-Soil Response to Brief Intense Radiative Heating.

Descriptive Note : Technical rept. 31 Dec 84-31 Oct 86,

Corporate Author : TRW ELECTRONICS AND DEFENSE SECTOR REDONDO BEACH CA

Personal Author(s) : Fendell, F. E. ; Carrier, G. F. ; Chang, D. J. ; Bronstein, M. P.

Report Date : 30 NOV 1986

Pagination or Media Count : 79

Abstract : This theoretical study estimates the distribution of temperature, and of lofted particles (if any), which, for various soil conditions, would prevail at shock arrival. The distribution of sound speed is quantitatively characterized with height at shock arrival, with implications for shock structure. The amount of particulate matter that is lofted sensitively depends on the particle-size distribution. Particles with characteristic size greater than 100 microns are held by gravity against a one-meter-per-second gaseous stream, whereas material of one-tenth that size readily accompanies the stream. The capacity of steam to fluidize (unconsolidated) soil grains has significant consequences for the speed of sound, since modest dust loading countervails temperature enhancement in establishing the equilibrium sound speed of the medium. For an average flux of 400 W/sq-cm over 1-2 s for a soil with water saturation 0.2, and with extinction coefficient 6/cm for light in the visible, would lead to a sound speed of roughly 1.5 times that of ambient air over roughly an 8-m-high near-ground layer for soil with particles larger than 60um; neither such sound speed enhancement in, nor such thickness of, the thermal layer is anticipated for a soil of fines.

Descriptors :   *BLAST, *DUST, *NUCLEAR EXPLOSION SIMULATION, ACOUSTIC VELOCITY, AIR, AIRBORNE, ARRIVAL, DISTRIBUTION, EQUILIBRIUM(GENERAL), ESTIMATES, FINES, GRAVITY, HEIGHT, INTENSITY, LAYERS, OPTIMIZATION, PARTICLE SIZE, PARTICLES, PARTICULATES, PRECURSORS, HEATING, SHOCK, SOILS, STEAM, TEMPERATURE, THERMAL ANALYSIS, THERMAL PROPERTIES, THICKNESS, DENSITY, GASES, DUST CLOUDS, MULTIPHASE FLOW, THERMAL RADIATION, DYNAMIC RESPONSE, CONVECTION.

Subject Categories : Nuclear Weapons

Distribution Statement : APPROVED FOR PUBLIC RELEASE