Order number “set 5 with1OFRICKAL-USE ONLY page 32 « 801. KEYWORD (S) possible to calculate the stiffness changes caused by the blast loading. Calculated values of the preshot frequencies, assuming a rigid foundation, were considerably greater than the measured values. Ground stiffnesses calculated from the measured frequencies appear to be of the correct order of magnitude. Damping ratios calculated from the resonance curves are low compared with values obtained by other experimenters. GREENHOUSE/ground motion ;STRUCTURES/blast loading 7 GREENHOUSE; STRUCTURES Item 56 150. 110. 70. 710. 371. 34. 950. REPORT NUMBER PRIMARY TITLE (M) PERSONAL AUTHOR( M) CORPORATE SOURCE PUB. DATE (YYMMDD ) CLASSIF. LEVEL T EXT ABSTRACT NOLTR--64-103 Physics of the base surge Young, G.A. Naval Ordnance Lab., White Oak, underwater nuclear explosion 801. KEYWORD(S) MD (USA) 650617 Unclassified The column and base surges formed by the (Test Baker) in Operation Crossroads in 1946 were measured in detail. The new data were used to formulate a physical explanation of the base surge behavior and to develop prediction techniques. The primary surge originated as a spillout of sea-water jets which broke into spray and formed a dense toroidal shaped cloud. Computations were made for the coalescence and rainout of drops and a theory was developed for the mixing of the surge with the air. The late behavior was strongly influenced by the convectively unstable atmosphere and the high relative humidity. The effects of other meteorological conditions were described. 232 references. BAKER BURST/base surge ;BAKER BURST/column formation ;HUMIDITY Item 57 150. 110. 70. 710. 371. 34. 950. NOLTR--62-191 REPORT NUMBER PRIMARY TITLE (M) PERSONAL AUTHOR( M) CORPORATE SOURCE PUB. DATE (YYMMDD ) CLASSIF. LEVEL T EXT ABSTRACT Liquid model studies of the base surge Swift, E. Jr. Naval Ordnance Lab., White Oak, MD (USA) 621001 ~ Unclassified When a constrained column of dense liquid standing on the bottom of a tank of water is released suddenly, it sinks and flows outward radially along the bottom. This action simulates the early motion of the base surge from shallow underwater explosions. Such liquid model experiments are described, scaling laws are derived, and IO034Ob OFFICIAL USE ONLY