Effects of Marine Growth on Hydrodynamic Coefficients of Rigid Tubular Cylinders

Abstract

In this paper the wave induced hydrodynamic forces and the corresponding hydrodynamic coefficients for a 42 mm diameter model pipe subjected to regular waves was investigated experimentally and the results were compared with the responses of a similar rigid cylinder fitted with marine growth. The main objective of this study was to quantify the effects of marine growth on the hydrodynamic forces experimentally and determine the associated hydrodynamic coefficients. The experimental data were generated from a set of wave tank model tests and the results were scaled up using a scale factor of 1:55. The thickness of marine growth applied on the model pipe was varied with respect to the water depth in the ratio of 3:2:1. Regular waves were generated with wave heights ranging from 0.02 m to 0. 2 m for modal period varying from 0.6 s to 3.25 s. The tests were conducted for Keulegan-Carpenter number ranging from 3.9 to 23.3. The findings of the experimental results revealed that increasing the thickness of the full scale prototype cylinder by 110 mm due to marine growth fittings, has increased the overall wave hydrodynamic forces by 16 to 90% depending on the wave heights and the wave frequencies at which the model was tested, proving that the drag coefficients have considerably increased.

Analysis of tripod supported offshore wind turbines under conditions of marine growth

“…Detailed experimental studies have been conducted on tubular structures to assess the variation of the hydrodynamic coefficients in the Ocean Engineering, 2020 presence of marine growth [8,9]. The work done by Sarpkaya et al [10] has been taken into consideration for high values of Keulegan-Carpenter (K-C) number, where the dependency of mass and drag coefficients from K-C is displayed for values till K-C=100.…”

Oceanography and Marine Biology

“…As these natural systems develop and their presence increases over time, they will affect the structure's performance and interact with the surrounding environment. For example, marine growth could increase the crest height of a breakwater and further dissipate local wave energy, or alternatively marine growth on a pile encasement could alter flow patterns and change drag forces around the structure (Yacouby-Al et al 2014).…”