OTEC cold water pipe design for problems caused by vortex-excited oscillations

Technical Report · Fri Mar 14 00:00:00 EST 1980

DOI:https://doi.org/10.2172/5360514· OSTI ID:5360514

Griffin, O. M.

Vortex-excited oscillations of marine structures result in reduced fatigue life, large hydrodynamic forces and induced stresses, and sometimes lead to structural damage and to diestructive failures. The cold water pipe of an OTEC plant is nominally a bluff, flexible cylinder with a large aspect ratio (L/D = length/diameter), and is likely to be susceptible to resonant vortex-excited oscillations. The objective of this report is to survey recent results pertaining to the vortex-excited oscillations of structures in general and to consider the application of these findings to the design of the OTEC cold water pipe. Practical design calculations are given as examples throughout the various sections of the report. This report is limited in scope to the problems of vortex shedding from bluff, flexible structures in steady currents and the resulting vortex-excited oscillations. The effects of flow non-uniformities, surface roughness of the cylinder, and inclination to the incident flow are considered in addition to the case of a smooth cyliner in a uniform stream. Emphasis is placed upon design procedures, hydrodynamic coefficients applicable in practice, and the specification of structural response parameters relevant to the OTEC cold water pipe. There are important problems associated with in shedding of vortices from cylinders in waves and from the combined action of waves and currents, but these complex fluid/structure interactions are not considered in this report.

• Research Organization: Naval Research Lab. (NRL), Washington, DC (United States)
• DOE Contract Number: EG-77-A-29-1078
• OSTI ID: 5360514
• Report Number(s): DOE/NOAA/OTEC-28; NRL-MR-4157
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
OCEAN THERMAL POWER PLANTS
OSCILLATIONS
PIPES
CYLINDERS
DESIGN
FAILURES
FATIGUE
HYDRODYNAMICS
LIQUID FLOW
MECHANICAL VIBRATIONS
OFFSHORE PLATFORMS
RESONANCE
RESPONSE FUNCTIONS
SERVICE LIFE
STRESSES
VORTICES
WATER CURRENTS
WATER WAVES
WAVE FORCES
CURRENTS
FLUID FLOW
FLUID MECHANICS
FUNCTIONS
MECHANICAL PROPERTIES
MECHANICS
POWER PLANTS
SOLAR POWER PLANTS
140800* - Solar Energy- Ocean Energy Systems