Document Details


Title:
OPERATION HARDTACK-PROJECT 1.1: UNDERWATER PRESSURES FROM UNDERWATER BURSTS (DELETED)
Author(s):
SWIFT, E [WATERWAYS EXPERIMENT STATION, VICKSBURG, MS]; BAMPFIELD, J F [WATERWAYS EXPERIMENT STATION, VICKSBURG, MS]; INGRAM, L [WATERWAYS EXPERIMENT STATION, VICKSBURG, MS]; KIRKLAND, E R [WATERWAYS EXPERIMENT STATION, VICKSBURG, MS]; NEWTON, V S [WATERWAYS EXPERIMENT STATION, VICKSBURG, MS]; NIFFENEGGER, C R [WATERWAYS EXPERIMENT STATION, VICKSBURG, MS]; PRICE, R S [NAVAL ORDNANCE LABORATORY, WHITE OAK]; THIEL, M A [WATERWAYS EXPERIMENT STATION, VICKSBURG, MS]
Subject Terms:
UNDERWATER EXPLOSIONS; WAHOO EVENT; UMBRELLA EVENT; HARDTACK I OPERATION; MEASURING METHODS; SHOCK WAVES; EQUIPMENT; PROCEDURES
Document Location:
Location - NNSA/NSO Nuclear Testing Archive Address - P.O. Box 98521 City - Las Vegas State - NV Zip - 89193-8521 Phone - (702)794-5106 Fax - (702)862-4240 Email - CIC@NV.DOE.GOV
Document Type:
REPORT
Publication Date:
1960 Aug 15
Declassification Status:
Sanitized
Document Pages:
0059
Accession Number:
NV0051012
Document Number(s):
WT1606EX
Originating Research Org.:
WATERWAYS EXPERIMENT STATION, VICKSBURG, MS
OpenNet Entry Date:
1994 Aug 26
Description/Abstract:
FREE-FIELD UNDERWATER PRESSURES WERE MEASURED DURING SHOTS WAHOO AND U MBRELLA IN ORDER TO PROVIDE BASIC DATA FOR THE DETERMINATION OF CRITIC AL DAMAGING RANGES AND SAFE DELIVERY DISTANCES OF SUBMARINES AND SURFA CE VESSELS IN THE VICINITY OF UNDERWATER NUCLEAR DETONATIONS. PRESSUR ES WERE RECORDED ON MAGNETIC TAPE FROM PIEZOELECTRIC AND ELECTROMECHAN ICAL PICKUPS IN THE WATER: THE ELECTRONIC RECORDING EQUIPMENT WAS SELF -CONTAINED AND OPERATED AUTOMATICALLY. BACKUP WAS PROVIDED BY MECHANI CAL GAGES; BOTH SELF-CONTAINED PRESSURE-TIME GAGES AND BALL-CRUSHER PE AK-PRESSURE GAGES WERE USED. ON WAHOO, A 500-FOOT-DEEP SHOT IN 3,200 FEET OF WATER, THE MEASUREMENTS WERE TO PROVIDE A CHECK ON RESULTS OBT AINED DURING OPERATION WIGWAM, AND TO YIELD SOME INFORMATION ON REFRAC TION BY THERMAL GRADIENTS, BOTTOM REFLECTIONS, THE CAVITATION PULSE AN D ANY SUBSEQUENT PULSES. UNDERWATER PRESSURES AT DEPTHS DOWN TO 1,875 FEET WERE OBTAINED FROM THE ELECTRONIC RECORDERS AT A RANGE OF 2,300 FEET, AND FROM THE MECHANICAL GAGES AT DEPTHS DOWN TO 500 FEET AT 2,76 3, 3,400, AND 15,000 FEET FROM SURFACE ZERO. THE ELECTRONIC EQUIPMENT ON TWO OTHER TARGET SHIPS DID NOT OPERATE DUE TO FAILURE IN TIMING SI GNALS. AT 300 FEET, BOTH PRESSURE AND DURATION OF THE SHOCK WAVE WERE LESS (APPROXIMATELY 15 PERCENT) THAN WOULD BE EXPECTED IN ISOVELOCITY WATER; CALCULATIONS BASED ON THE REFRACTION OF THE SHOCK WAVE BY THE TEMPERATURE STRUCTURE OF THE WATER AGREE WITH THE MEASURED POINT. THE APPARENT REFLECTION COEFFICIENT OF THE BOTTOM WAS 0.31. A CAVITATION PULSE OF RELATIVELY LOW AMPLITUDE WAS FOUND. AN UNEXPECTED SERIES OF FOUR LOW-AMPLITUDE PULSES AT AROUND 30 SECONDS AFTER ZERO TIME APPEAR ED ON ALL RECORDS. FOR UMBRELLA, A SHOT FIRED ON THE BOTTOM IN 148 FE ET OF WATER, THE MEASUREMENTS WERE TO PROVIDE INFORMATION ON THE PROPA GATION OF A SHOCK WAVE IN SHALLOW WATER; IN PARTICULAR, TO FIND PEAK P RESSURES AND DURATIONS OF THE SHOCK WAVE AS A FUNCTION OF DISTANCE AND DEPTH, THE NATURE AND MAGNITUDE OF THE ASSOCIATED GROUND WAVE, AND TH E MAGNITUDE OF THE CAVITATION PULSE. UNDERWATER PRESSURES WERE MEASUR ED AT SIXTEEN STATIONS. RECORDS WERE OBTAINED AT DISTANCES OF 500 TO 8,000 FEET FROM SURFACE ZERO, AND AT DEPTHS FROM 10 FEET DOWN TO 130 F EET. MOST OF THE PRESSURE-TIME RECORDINGS WERE AT DISTANCES GREATER T HAN 1,500 FEET. A GROUND WAVE OF UNEXPECTEDLY LOW AMPLITUDE APPEARED ON ALL RECORDS EXCEPT AT THE 500-FOOT STATION; ITS APPARENT VELOCITY W AS 9,300 FT/SEC. SHOCK-WAVE PRESSURES DECREASED NEAR THE BOTTOM AT AL L DISTANCES; PRESSURES VERY CLOSE TO THE SURFACE ALSO WERE LOW. MID-D EPTH PEAK PRESSURES AGREED WITH THEORETICAL PREDICTIONS: THEY FELL BE TWEEN RESULTS SCALED UP FROM 100-LB TNT CHARGES FIRED OVER SANE AND OV ER MUD, AND ARE MUCH LOWER THAN FREE WATER VALUES. A CAVITATION PULSE ORIGINATING AT ABOUT 2,000 FEET FROM SURFACE ZERO, APPEARED AT ALL ST ATIONS.


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