Numerical investigation of the landing manoeuvre of a crew transfer vessel to an offshore wind turbine

Abstract

Crew transfer vessels are a fast and cost-effective means of transportation to bring service personnel and technical equipment to an offshore wind turbine. The landing manoeuvre of such service vessels is a complex coupled process involving the ship's motion in the seaway and the frictional contact between the fender and the boat landing. With the help of numerical simulations, we aim to identify the limit conditions under which a safe crew transfer can still be ensured, and to investigate innovative transfer concepts which serve to avoid severe accidents. In our research, we draw on a partitioned solution strategy which has already been successfully applied to other sophisticated multi-field phenomena and which allows to reuse specialised existing solvers for the solution of the involved subproblems.

O&M of Crew Transfer Vessels against Floating Wind Turbines -- Modelling the Water Run-Up Effect During Personnel Transfer in Waves with Short Periods

“…We assume the friction coefficient between boat fender and floater boat landing to be the ratio of the hull wave-induced vertical forces by the sum of the hull waveinduced horizontal forces and propeller thrust [4]. The Catamaran (CAT) CTV used is a twin Wigley hull, based on Hamburg Facility (HSVA) model tank test [5].…”

“…Where tT and tN are the time phase corrections required to get the calculated wave vertical and horizontal forces T(t) and N(t) on Wigley hull in phase with the HSVA real hull test results [4] [5]. Fig.…”

“…The water depth is 29m. The studied monopile has 5m diameter [5] (figures3 and 4). Since CTV is wider than monopile, the CTV is not masked from incidental waves: ac = a(fig.…”

Offshore monopile in the southern North Sea: part II, simulated hydrodynamics and loading

“…This contact is maintained through a steady thrust from the CTV motor throughout crew transfer. If the hydrodynamic force incident on the vessel overcomes the frictional force, the CTV can experience slippage, during which the vessel loses contact with the turbine or undergoes unanticipated motion (Josse et al, 2011;König et al, 2017;Edesess et al 2017). When vessel slippage occurs, the repair workers are in potential danger and the possibility exists of additional economic losses due to incomplete repairs.…”

“…Previously, Josse et al (2011) presented a mechanical system in which the hydrodynamic forces were ignored and the angle of the vessel against the monopile was the only parameter assumed to affect the frictional contact. However, König et al (2017) emphasised the necessity of calculating the hydrodynamic forces within the wave field to improve the determination of wave loading on the vessel. This study assumed that hydrodynamic forces have the largest effect on the frictional contact and an approximation for the diffracted wave height as a function of wave length was derived but no attempt was made to extend the calculations to quantify the local water particle kinematics within this region.…”