The Basque Energy Agency commissioned the Mutriku Wave Power Plant, using an Oscillating Water Column technology in 2011, and although the cumulative total power has been over 3 GW/h until 2023, the initial expectations of efficiency and LCoE have not been accomplished. This paper proposes a series of modifications to the breakwater and chamber geometry of the plant to increase energy production and efficiency. These proposed improvements were tested in experimental campaigns in the modular wave flume in the Energy Engineering Department at the University of the Basque Country, using a mock-up of the original installation. Some results also came from validated numerical simulations, showing that the response amplitude operator and the capture width ratio values were better than those in the original L-shaped power plant. The best configurations appear to be U-shaped and when harbor walls are used. In conclusion, this paper reports the proper configurations and localizations for new wave power plants that could be commercially competitive.

The research presented was conducted to quantify the effects of butterfly and gate valves located upstream water meters with diameters larger than 50 mm. Errors caused by these valves can have an enormous financial impact taking into consideration that a small percentage of variation in the error of a large meter is typically related to a significant volume of water. The uncertainty on the economic impact that a valve installed upstream of a medium size water meter leads to many water utilities to oversize the meter chambers in order to mitigate the potential negative errors. Most manufacturers approve their meters for a specific flow disturbance sensitivity class according to the standard ISO 4064-1:2018. Under this classification, a correct operation of the meters requires a certain length of straight section of pipe upstream the meter. However, this classification of the meters cannot consider all types of flow perturbances. For this study, two types of valves, butterfly and gate, were tested upstream ten brand-new water meters from six different manufacturers constructed in four different metering technologies: single-jet, Woltmann, electromagnetic and ultrasonic. In each meter unit was tested at five flow rates, from minimum to the overload flow rates. The tests were conducted with valves set in different orientations, closing degrees, and upstream distances from the water meters under study. The research shows that the valves used can produce significant deviations in the measuring errors with respect the errors found for undistorted working conditions.

The focus of this study is on large flow meters, for which there is limited information due to their large size, making testing and research challenging. This research was conducted to quantify the effects of various accessories located upstream of these meters. Even a small percentage of variation in error can correspond to a significant volume of water. Accurate meters are crucial in many applications that involve large volumes of water as precise flow measurements are necessary for smooth and efficient processes while avoiding costly errors and downtime. Inaccurate large water meters can have far-reaching implications, such as overbilling or underbilling and production inefficiencies, which result in wasted resources and energy. Furthermore, inaccurate flow measurements can lead to environmental consequences as industries must comply with strict regulations regarding wastewater discharge limits. Uncertainty about the economic impact of an accessory installed upstream of a medium-sized water meter leads many water utilities to oversize the meter chambers to mitigate potential negative errors. In this study, six types of elements were tested upstream of ten brand-new water meters from six different manufacturers, constructed using four different metering technologies: single-jet, Woltmann, electromagnetic, and ultrasonic. Each meter unit was tested at five flow rates, ranging from the minimum to overload. The tests were conducted with accessories set in different orientations and distances upstream of the water meters under study. The research shows that the accessories used can cause significant deviations in measuring errors compared to the regular errors found under undisturbed working conditions.

Time efficiency is a critical concern in Computational Fluid Dynamics (CFD) simulations of industrial applications. Despite the extensive research to improve the underlying numerical schemes to reduce the processing time, many CFD applications still need to improve on this issue. Reduced-Order Models (ROM) appeared as a promising alternative for significantly enhancing cost-effectiveness. The dimension of the initial problem is reduced significantly while keeping an acceptable level of accuracy. Proper Orthogonal Decomposition (POD), a data analysis technique, is widely used to construct a ROM to solve Euler and Navier-Stokes equations in CFD. Many aspects, however, need to be improved. In this paper, first, a general upper-bound error formula is derived, and second, a mesh-adaptivity based algorithm for snapshot locations in parameter space is provided (a sensitive step for POD-based ROM) in the context of Partial Differential Equations (PDE). The method’s efficiency is demonstrated through numerical tests by comparison to exact solutions and numerical results of a finite volume scheme on inviscid flow over a NACA0012.