A computational methodology for the hydrodynamic analysis of horizontal axis marine current turbines is presented. The approach is based on a boundary integral equation method for inviscid flows originally developed for marine propellers and adapted here to describe the flow features that characterize hydrokinetic turbines. For this purpose, semi-analytical trailing wake and viscous flow correction models are introduced. A validation study is performed by comparing hydrodynamic performance predictions with two experimental test cases and with results from other numerical models in the literature. The capability of the proposed methodology to correctly describe turbine thrust and power over a wide range of operating conditions is discussed. Viscosity effects associated to blade flow separation and stall are taken into account and predicted thrust and power are comparable with results of blade element methods that are largely used in the design of marine current turbines. The accuracy of numerical predictions tends to reduce in cases where turbine blades operate in off-design conditions.

A computational methodology for the hydrodynamic analysis of horizontal axis marine current turbines is presented. The approach is based on a boundary integral equation method for inviscid flows originally developed for marine propellers and adapted here to describe the flow features that characterize hydrokinetic turbines. To this purpose, semi-analytical trailing wake and viscous-flow correction models are introduced. A validation study is performed by comparing hydrodynamic performance predictions with two experimental test cases and with results from other numerical models in the literature. The capability of the proposed methodology to correctly describe turbine thrust and power over a wide range of operating conditions is discussed. Viscosity effects associated to blade flow separation and stall are taken into account and predicted thrust and power are comparable with results of blade element methods that are largely used in the design of marine current turbines. The accuracy of numerical predictions tend to reduce in cases where turbine blades operate in off-design conditions.

In this study, we investigate how the interruptions and non-deterministic operational behavior at the base port affect the installation time and resource utilization. Scenarios such as equipment breakdown are examples of interruption occurrences. The work provides a detailed study of realistic port tasks and scenarios. The operations at the base port and those between the port and the offshore site include fabrication, assembly, load-out, ballasting tasks of the floater, turbine assembly, integrated floater-turbine towing, and hook-up operations. The reference floating substructure, adopted in this study, is an innovative submersible platform concept, developed by CENER for the INNWIND 10MW wind turbine. SimPy, an open-source Python-based package is used to model critical port and installation procedure operations using Discrete Event Simulation. The results are obtained for a range of disruption frequency from 0.0005 to 0.01 (hr−1) and repair times of 8 and 16 (hrs). Results showed an increase in the installation time when disruption frequency and repair time increased. The predicted delay in the installation operations was significant in case of higher disruption frequencies and could reach 21%, compared to the reference case without any failure. Moreover, the utilization of fabrication machines decreased by increasing the disruption rate and repair time. For example, utilization of welding machines for pontoons fabrication reduced by 19% for a high disruption frequency of 0.01 (hr−1), compared to the reference case.

A computational procedure for the hydrodynamicanalysis and design of horizontal-axis tidal turbinesis presented and numerical applications are discussed. Themethodology combines an original design algorithm and aturbine hydrodynamics model valid for arbitrary 3D flows.Different from standard design methods based on bladeelement models, 3D-flow corrections are not necessary.Blade geometry parameters are determined with the objectiveto maximize power at given design Tip Speed Ratio(TSR), whereas a constraint is introduced in order to limitturbine thrust at TSR higher than the design condition.Numerical applications include the design of a laboratoryscaleturbine and a full-scale turbine for the exploitationof tidal streams in the Messina strait. Alternative designsolutions obtained by varying the design TSR are comparedin terms of energy output as well as mechanical loadstransferred to the powertrain.