Scour around pipelines in combined waves and current
- Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Hydrodynamics and Water Resources
The paper presents the results of an experimental study on scour below pipelines subject to combined waves and current. Irregular waves were used. The measured scour characteristics (namely, the scour depth and the scour width) were obtained as function of U{sub c}/(U{sub c} + U{sub m}) and for various values of the Keulegan-Carpenter number, KC, in which U{sub c} is the undisturbed current velocity at the level of the pipe center and U{sub m} is the maximum undisturbed orbital velocity at the sea bottom. KC ranges from 5 to about 50, and U{sub c}/(U{sub c} + U{sub m}) from 0 to 1. The results show that the scour depth may increase or decrease when a current is superimposed on waves, depending on the values of KC and U{sub c}/(U{sub c} + U{sub m}). The results further indicate that the scour depth attains its steady-current value for U{sub c}/(U{sub c} + U{sub m}) larger than about 0.7. The design equations relating the scour depth to KC and U{sub c}/(U{sub c} + U{sub m}) were obtained, based on the present data.
- OSTI ID:
- 400959
- Report Number(s):
- CONF-9606279--; ISBN 0-7918-1494-7
- Country of Publication:
- United States
- Language:
- English
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