To get the accurate wave loads on the small-scale cylinders on the platforms, not only the incident wave but also the diffraction and radiation wave should be considered. By taking the wave diffraction from a fixed large-scale cylinder as an example, wave loads on small-diameter cylinders in the diffraction wave field are calculated by Morison formula in this paper. A time-domain numerical model on wave diffraction from large-scale structures is developed with a higher-order boundary element method (HOBEM). Then the velocity and acceleration of any water particle in the fluid domain can be produced from the solved diffraction potential. Results show that the incident wave force is even equal to diffraction wave force when the diameter of the large-scale cylinder is 8 times as great as the small-scale one; And the total force is different with the locations of the small-scale cylinder. The maximum total force is 1.57 times as great as only the incident wave force. Therefore, the wave force on the stake produced by the diffraction waves due to the existence of upper structures should be considered in the practical engineering.
Geng, Bao-Lei; Teng, Bin; and Ning, De-Zhi
"A TIME-DOMAIN ANALYSIS OF WAVE FORCE ON SMALL-SCALE CYLINDERS OF OFFSHORE STRUCTURES,"
Journal of Marine Science and Technology: Vol. 18
, Article 12.
Available at: https://jmstt.ntou.edu.tw/journal/vol18/iss6/12