Moving boundary wave generation is widely used in laboratory wave flume studies, but the relation between the kinetic energy scale of a push plate and the measurable free surface wave energy remains insufficiently characterized under nonlinear, finite depth conditions. In this study, a two-dimensional volume of fluid numerical wave tank is used to examine the energy conversion efficiency of a push plate wavemaker. The numerical and experimental estimates of apparent energy conversion efficiency differed by 5.72
This study presents a long-term analysis of three different configurations of a spar-type floating wind turbine platform. The probability distributions of long-term motion responses and tower base bending moments for the floating platforms are obtained from wave data in the North Atlantic Ocean. The transfer functions of the platform motions and tower base forces are obtained from aero-servo-hydro-elastic simulations. The long-term distribution is based on transfer functions and theoretical spectra for the sea states that describe the wave data. Responses of the spar-type floating wind turbine platforms are obtained for surge, sway, heave, roll, pitch, and yaw motions. The transfer function for these responses of the floater is obtained using the aero-servo-hydro-elastic simulation. Four design wave-spectrum models that represent the sea states are selected for the present study to evaluate the long-term response spectra. A comparative study of the three spar configurations is performed to support design and safety considerations for floating wind turbines. The study will help to optimize design, reduce costs, implement life-extension strategies, and enable risk-informed decision-making, contributing to the safe and sustainable deployment of floating offshore wind energy systems.
Tsunami bores generate short-duration, highly turbulent flows that impose intense bed shear stress on coastal structures, often leading to toe scour and structural instability. This study experimentally examines the transient evolution of bed shear stress and scour formation at four seawall geometries (box, curve, slope, and step types) using a dam-break wave testing facility and high-resolution Particle Image Velocimetry (PIV). Controlled bores with initial reservoir depths (H = 13, 15, 17 cm) propagated over a movable bed of 1 mm glass beads for scour experiments. PIV measurements on an identical fixed-bed setup from which near-bed shear rate and bed shear stress were derived. Results show scour initiated within the first second after impact and corresponded to brief shear intensifications rather than sustained bed shear stress levels. The box-type seawall produced the deepest scour due to a concentrated downward jet at the toe, even though its peak bed shear stress was lower than that of the other geometries. The curve, slope, and step-type seawalls generated higher instantaneous bed shear stress values but negligible scour because their geometries redirected momentum and shortened the duration of near-bed shear. These results indicate that the bed shear stress magnitude alone is not enough to determine sediment response, but that the duration and direction of transient shear events determine the initiation of motion under tsunami-like bores. Profiles with curved, sloped and stepped form were especially effective in reducing toe scour by dispersing bore momentum and limiting the bed exposure to high shear. This study provides integrated laboratory dataset linking PIV-derived transient bed shear stress with measured scour initiation under wet-bed tsunami bore conditions.
This study introduces the Generalised Admiralty Equation (GAE) to estimate the required calm-water propulsion power using semi-empirical closed-form formulations and a modified Admiralty coefficient ( A_c' ), with limited input data. Additional corrections for protruding appendages, external domes, wind, waves, or other external resistance contributions may subsequently be incorporated using appropriate supplementary methods. The usefulness of the method is particularly relevant for estimating the Energy Efficiency Design Index (EEDI) and optimizing ship configurations at the early design stage. Validation across several hull types shows deviations of approximately 4
India's coastline, extending over approximately 11,000 km, possesses an estimated wave energy potential of about 40 GW; however, its utilization remains limited. This review examines the key factors governing wave farm (WF) performance, including device interactions, array spacing, layout optimization, control strategies, and site-specific conditions, with particular emphasis on their relevance to the Indian coastline. The Indian wave climate, characterized by low-to-moderate wave energy and pronounced seasonal variability, differs significantly from high-energy regions, requiring region-specific approaches for wave farm development. The review indicates that point absorber and attenuator-type wave energy converters (WECs) are among the most suitable technologies for deployment along the southern and western coasts of India. It further highlights that existing Indian studies have predominantly focused on individual WEC performance under simplified conditions, with comparatively limited focus on array hydrodynamic interactions, irregular wave conditions, and validation in real-sea environments. The findings indicate the need for integrated wave farm design frameworks that combine realistic wave climates, optimized array layouts, device interaction effects, and techno-economic assessments to facilitate practical deployment and support the advancement of wave energy as a component of India's blue economy.
