Mooring Analysis of Duct-Type Tidal Current Power System in Shallow Water

Authors: Chul H. Jo, Do Y. Kim, Bong K. Cho, Myeong J. Kim

Abstract:

The exhaustion of oil and the environmental pollution from the use of fossil fuel are increasing. Tidal current power (TCP) has been proposed as an alternative energy source because of its predictability and reliability. By applying a duct and single point mooring (SPM) system, a TCP device can amplify the generating power and keep its position properly. Because the generating power is proportional to cube of the current stream velocity, amplifying the current speed by applying a duct to a TCP system is an effective way to improve the efficiency of the power device. An SPM system can be applied at any water depth and is highly cost effective. Simple installation and maintenance procedures are also merits of an SPM system. In this study, we designed an SPM system for a duct-type TCP device for use in shallow water. Motions of the duct are investigated to obtain the response amplitude operator (RAO) as the magnitude of the transfer function. Parameters affecting the stability of the SPM system such as the fairlead departure angle, current velocity, and the number of clamp weights are analyzed and/or optimized. Wadam and OrcaFlex commercial software is used to design the mooring line.

Keywords: Mooring design, parametric analysis, response amplitude operator, single point mooring.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1124395

References:

[1] Jo, C.H., Lee, K.H., Yim, J.Y., Che, K.S., Performance evaluation of TCP device with upstream duct installation, Proceeding of the Korean association of ocean science and technology societies conference 2009; 77-80.
[2] Khunthongjan, P., Janyalertadun, A., A study of diffuser angle effect on ducted water current turbine performance using CFD, Songklanakarin journal of science and technology 2012; 34:61-67.
[3] Kim, J.W., Lee,S.H., A study on seawater flow characteristics inside the shrouds used in tidal current generation systems for various geometric angles under constant tidal current velocity, Journal of the Korean society of coastal and ocean engineers 2012; 24:77-83.
[4] Luguet, R., Bellevre, D., Frechou, D., Perdon, P., Guinard, P., Design and model testing of an optimized ducted marine current turbine, International journal of marine energy 2013; 2:61-80.
[5] Jo, C.H., Kim, D.Y., Hwang, S.J., Goo, C.H., Shape Design of the Duct for Tidal Converters Using Both Numerical and Experimental Approaches, Energies, (online), 2015.
[6] Cunff, C.L., Ryu, S., Heurtier, J.M., Duggal, A.S., Frequency-domain calculations of moored vessel motion including low frequency effect, Proceedings of the 27th international conference on offshore mechanics and arctic engineering 2008.
[7] Yang, W.S., Hydrodynamic analysis of mooring lines based on optical tracking experiments, Texas A&M University, Ph.D. thesis 2007.
[8] Sachithanathamoorthy, K., Design and analysis of tension leg anchor systems for floating windmills, Norwegian University of Science and Technology, Master’s thesis 2012.
[9] Hall, M.T.J., Mooring line modelling and design optimization of floating offshore wind turbines, University of Victoria, Master’s thesis 2013.