LOCAL IMPACT PRESSURES IN BASICALLY PRISMATIC TANKS (OBO/LNG)
Slosh loads are of particular importance in prismatic tanks without internal members of appreciable size, as in OBO, gas, and products carriers. In these tanks, travelling waves when the cargo-levels, produce impulsive pressure loads that are probably the most difficult slosh loads from the design viewpoint. The main reasons for the difficulty are that the magnitude and duration of the pressure pulses are of a random nature, their distribution in time and space is hard to determine, and the scale effects are more uncertain than those of other slosh loads. After discussing the characteristics of these impact pressures in prismatic tanks, the Author, of Det Norske Veritas, examines the influence of various geometric and dynamic parameters on the pressures. This examination is based on results from an investigation sponsored by the U.S. Maritime Administration, the Author's present purpose is to condense the most essential findings of this investigation and re-evaluate them from a practical viewpoint. Relevant experimental work carried out in the Marad investigation is discussed under the headings: Tank Model and Instrumentation; Pressures at Different Tank Regions; Influence of Fill Depth; Influence of Period and Amplitude of Excitation; Spatial Distribution of Impact Pressures. Approximation to a realistic long-term distribution is then considered, and a long-term distribution of pitch amplitudes is calculated. Finally, the influence of fluid properties (viscosity, boiling, and in particular compressibility) on the scale effects in such model tests is discussed.
- Seminar on Liquid Sloshing.
Norske VeritasGrenseveien 92, Etterstad
Oslo 6, Norway
- Olsen, H
- Publication Date: 1976-5
- Features: References;
- Pagination: 22 p.
- TRT Terms: Equipment tests; Free surface; Impact; Liquefied gases; Liquefied natural gas; Pressure; Sloshing; Stresses; Structural analysis; Tankers; Tanks (Containers)
- Old TRIS Terms: Free surface effects; Impact pressure; Tank instrumentation; Tank stresses; Tank testing; Tanker structural analysis
- Subject Areas: Design; Marine Transportation;
- Accession Number: 00152585
- Record Type: Publication
- Source Agency: British Ship Research Association
- Report/Paper Numbers: Paper No. 10
- Files: TRIS
- Created Date: May 11 1977 12:00AM