| Popis: |
The weight coating requirements for assuring the on-bottom stability of several pipelines in the Arabian Gulf have been determined through an integrated design procedure including mathematical modelling for determining extreme wave conditions, field measurements of currents and physical model testing to establish the magnitude of the hydrodynamic forces. The paper describes in detail the hydro-dynamic model testing. By using the carriage technique, scales varying from 1:1 to 1:4 have been obtained in the laboratory. Further by applying directly measured wave induced bottom velocities from a given sea state the design conditions have been reproduced correctly in the laboratory reducing scaling errors to a minimum. Hydrodynamic coefficients for drag, inertia, and lift forces appropriate for use in common industry formulas for pipelines are determined for different environmental conditions. Reference tests in steady currents and regular waves support the conclusion of this study. The results cover a range of Keulegan-Carpenter numbers from 7 to 100 and Reynolds numbers from 10/sup 5/ to 10/sup 6/. |
