A general phase-based harmonic separation method for the hydrodynamic loading on a fixed structure in water waves of moderate steepness is proposed. An existing method demonstrated in the experimental study described by Zang et al. (Zang et al. 2010 In Proc. Third Int. Conf. on Appl. of Phys. Modelling to Port and Coastal Protection. pp. 1-7.) achieves the separation of a total diffraction force into odd and even harmonics by controlling the phase of incident focused waves. Underlying this method is the assumption that the hydrodynamic force in focused waves possesses a Stokes-like structure. Under the same assumption, it is shown here how the harmonic separation method can be generalized, so that the first four sum harmonics can be separated by phase control and linear combinations of the resultant time-histories. The effectiveness of the method is demonstrated by comparisons of the Fourier transforms of the combined time-histories containing the harmonics of interest. The local wave elevations around the focus time are also visualized for the first three harmonics in order to reveal the local dynamics driving components within the wave force time-history.

Insight is provided into focused wave group runup on a plane beach by means of laboratory wave flume experiments and numerical simulations. A focused wave group is presented as an alternative to an empirical description of the wave conditions leading to extreme runup. Secondorder correction to the laboratory wavemaker generation signal is observed to remove about 60% of the sub-harmonic error wave that would otherwise contaminate coastal response experiments. Laboratory measurements of the wave runup time history are obtained using inclined resistancetype wires and copper strips attached to the beach surface. The numerical wave runup model is based on hybrid Boussinesq-Nonlinear Shallow Water equations, empirical parameters for wave breaking and bed friction, and a wetting and drying algorithm. After calibration against experimental runup data, the numerical model reproduces satisfactorily the propagation, shoaling and runup of focused wave groups over the entire length of the wave flume. Results from a comprehensive parametric study show that both measured and predicted maximum runup elevations exhibit strong dependence on the linear focus amplitude of the wave group (linked to its probability of occurrence), the focus location, and the phase of the wave group at focus. The results also demonstrate that extreme runup events owing to focused wave incidence cannot be characterised using spectral parameters alone. The optimal band of focus locations shifts onshore as linear focus amplitude of the incident wave group increases. Optimisation of phase and focus location leads to a maximum runup elevation at each linear amplitude, and, when generated using second-order corrected paddle signals, the maximum runup appears to approach saturation

Inland fisheries can be diverse, local and highly seasonal. This complexity creates challenges for monitoring, and consequently, many inland fish stocks have few data and cannot be assessed using methods typically applied to industrial marine fisheries. In such situations, there may be a role for methods recently developed for assessment of data‐poor fish stocks. Herein, three established data‐poor assessment tools from marine systems are demonstrated to highlight their value to inland fisheries management. A case study application uses archived length, catch and catch‐per‐unit‐effort data to characterise the ecological status of an important recreational brown trout stock in an Irish lake. This case study is of specific use to management of freshwater sport fisheries, but the broader purpose of the paper was to provide a crossover between marine and inland fisheries science, and to highlight accessible data‐poor assessment approaches that may be applicable in diverse inland systems.

Ocean wave energy has been of interest since at least the mid-1970s and great advances in the understanding of the fundamental principles of wave energy extraction and converter modelling have been made using linear hydrodynamic analysis. This paper reviews efforts that have been made to use nonlinear hydrodynamics to analyse wave energy converter behaviour and performance. Both 'partially nonlinear' and fully nonlinear potential flow methods, as well as computational fluid dynamics methods solving the Navier-Stokes equations and smoothed particle hydrodynamics have been used for this purpose and are reviewed here. These more complex methods have been applied primarily to single devices, so array and mooring line interactions are not considered. While a number of studies have been performed in these areas and results are encouraging, further advances are required to give accurate prediction or reproduction of experimental results.

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