Boundary conditions generated by dynamic particles in SPH methods

Smoothed Particle Hydrodynamics is a purely Lagrangian method that can be applied to a wide variety of fields. The foundation and properties of the so called dynamic boundary particles (DBPs) are described in this paper. These boundary particles share the same equations of continuity and state as the moving particles placed inside the domain, although their positions and velocities remain unaltered in time or are externally prescribed. Theoretical and numerical calculations were carried out to study the collision between a moving particle and a boundary particle. The boundaries were observed to behave in an elastic manner in absence of viscosity. They allow the fluid particles to approach till a critical distance depending on the energy of the incident particle. In addition, a dam break confined in a box was used to check the validity of the approach. The good agreement between experiments and numerical results shows the reliability of DBPs

Modeling dam break behavior over a wet bed by a SPH technique

Dam break evolution over dry and wet beds is analyzed with a smoothed particle hydrodynamics model. The model is shown to accurately fit both experimental dam break profiles and the measured velocities. In addition, the model allows one to study different propagation regimes during the dam break evolution. In particular, different dissipation mechanisms were identified: bottom friction and wave breaking. Although breaking dominates over wet beds at the beginning of the movement, bottom friction becomes the main dissipation mechanism in the long run

Coastal warming under climate change: Global, faster and heterogeneous

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGThe assessment of expected changes in coastal sea surface temperature (SST) on a global scale is becoming increasingly important due to the growing pressure on coastal ecosystems caused by climate change. To achieve this objective, 17 Global Climate Models from CMIP6 were used, with data from historical and hist-1950 experiments spanning 1982–2050. This analysis highlights significant warming of coastal areas worldwide, with higher and more variable rates of warming than observed in previous decades. All basins are projected to experience an increase in coastal SST near 1 °C by mid-century, with some regions exhibiting nearshore SST anomalies exceeding 2 °C for the period 2031–2050 relative to 1995–2014. Regarding the Eastern Upwelling Boundary Systems, only the Canary upwelling system and the southern part of the Humboldt upwelling system manage to show lower-than-average SST warming rates, maintaining, to a certain extent, their ability to buffer global warmingXunta de Galicia | Ref. ED431C 2021/44Xunta de Galicia | Ref. ED481B-2021-108Fundação para a Ciência e a Tecnologia | Ref. UIDP/50017/2020Fundação para a Ciência e a Tecnologia | Ref. UIDB/50017/2020Ministerio de Ciencia e Innovación y Xunta de Galicia | Ref. PRTR-C17·I1Ministerio de Ciencia e Investigación | Ref. TED2021-129524B-I0

Assessing the complementarity of future hybrid wind and solar photovoltaic energy resources for North America

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGRenewable energy plays a key role into achieving the international targets for reducing global greenhouse gas emissions. Considering that these forms of energy are dependent on climate conditions and that their variability occurs at different time scales, it is important to analyze the complementarity to ensure a stable power supply to the grid in the context of climate change. A multi-model ensemble of 10 global climate models from the CMIP6 project was used to analyze the complementarity between wind and solar photovoltaic power in North America from 2025 to 2054 under the SSP2-4.5 scenario. This complementarity was evaluated using two indices that account for the similarity between the two resources (Similarity index, Si) and the temporal complementarity (Concurrency index, Ci). The combination of the two resources reduced spatial heterogeneity in terms of annual mean power in North America. The highest values of Si were detected west of California and in the Caribbean Sea, and the lowest were found in Mexico. Regarding Ci, the highest values were detected in ocean areas north of 30°N. Both indices were divided into four categories to assess the most suitable areas for combining wind and solar photovoltaic power. Coastal areas in the Gulf of Mexico and substantial areas in the Caribbean Sea are considered optimal in terms of complementarity. Inland, good complementarity was observed on the US-Canada border (e.g., the Great Lakes) and in northern areas such as Alaska or the Labrador Peninsula. The lowest values of complementarity were detected in Mexico.Ministerio de Ciencia e Innovación | Ref. PRTR-C17.I1Ministerio de Ciencia e Innovación | Ref. IJC2020-043745-IMinisterio de Ciencia e Innovación | Ref. PID2020-113245RB-I00Ministerio de Ciencia e Innovación | Ref. TED2021-129479A-100Fundação para a Ciência e a Tecnologia | Ref. UIDP/50017/2020Fundação para a Ciência e a Tecnologia | Ref. UIDB/50017/202

Combining offshore wind and solar photovoltaic energy to stabilize energy supply under climate change scenarios: A case study on the western Iberian Peninsula

La expansión de la energía renovable marina es una importante alternativa para la reducción de las emisiones de gases de efecto invernadero. Sin embargo, en Europa, la alta penetración de la energía eólica marina introduce intermitencia y variabilidad de energía en la red eléctrica existente. La energía solar fotovoltaica marina es otra alternativa tecnológica en consideración en los planes de descarbonización. Sin embargo, las futuras variaciones en el viento, la temperatura del aire o la radiación solar debido al cambio climático tendrán un gran impacto en los recursos de energía renovable. En este contexto, este estudio se centra en la evaluación de la energía marina en la costa de la Península Ibérica occidental, una región europea que abarca Portugal y la parte noroccidental de España. Utilizando una amplia fuente de datos de 35 simulaciones de un proyecto de investigación llamado CORDEX, este estudio investiga la complementariedad de las fuentes de energía eólica y solar marina con el objetivo de mejorar la estabilidad del suministro de energía de esta región hasta 2040. Aunque se ha demostrado que el recurso de energía eólica marina es mayor que el recurso fotovoltaico solar a escala anual, ambos recursos renovables mostraron una variabilidad significativa en energía a lo largo de la Península Ibérica occidental. Cuando se combinan ambas fuentes renovables, la estabilidad del recurso energético aumenta considerablemente a lo largo del año. El esquema propuesto de combinación de energía eólica y solar se evalúa mediante un método de clasificación de rendimiento llamado Delphi, teniendo en cuenta la estabilidad, el recurso, el riesgo y los factores económicos. El índice de clasificación total aumenta cuando la estabilidad del recurso se mejora mediante la consideración de la producción híbrida de energía eólica-fotovoltaica solar, especialmente a lo largo de las aguas cercanas a la costa.The expansion of marine renewable power is a major alternative for the reduction of greenhouse gases emissions. In Europe, however, the high penetration of offshore wind brings intermittency and power variability into the existing power grid. Offshore solar photovoltaic power is another technological alternative under consideration in the plans for decarbonization. However, future variations in wind, air temperature or solar radiation due to climate change will have a great impact on both renewable energy resources. In this context, this study focusses on the offshore energy assessment off the coast of Western Iberia, a European region encompassing Portugal and the Northwestern part of Spain. Making use of a vast source of data from 35 simulations of a research project called CORDEX, this study investigates the complementarity of offshore wind and solar energy sources with the aim of improving the energy supply stability of this region up to 2040. Although the offshore wind energy resource has proven to be higher than solar photovoltaic resource at annual scale, both renewable resources showed significant spatiotemporal energy variability throughout the western Iberian Peninsula. When both renewable resources are combined, the stability of the energy resource increased considerably throughout the year. The proposed wind and solar combination scheme is assessed by a performance classification method called Delphi, considering stability, resource, risk, and economic factors. The total index classification increases when resource stability is improved by considering hybrid offshore wind-photovoltaic solar energy production, especially along the nearshore waters.Ministerio de Economía, Industria y Competitividad | Ref. FJCI-2017-32577Agencia Estatal de Investigación | Ref. PID2020-113245RB-I00Fundação para a Ciência e a Tecnologia | Ref. UIDB/50017/2020Fundação para a Ciência e a Tecnologia | Ref. UIDP/50017/2020Xunta de Galicia | Ref. ED431C 2021/4

GPUs, a new tool of acceleration in CFD: efficiency and reliability on smoothed particle hydrodynamics methods

Smoothed Particle Hydrodynamics (SPH) is a numerical method commonly used in Computational Fluid Dynamics (CFD) to simulate complex free-surface flows. Simulations with this mesh-free particle method far exceed the capacity of a single processor. In this paper, as part of a dual-functioning code for either central processing units (CPUs) or Graphics Processor Units (GPUs), a parallelisation using GPUs is presented. The GPU parallelisation technique uses the Compute Unified Device Architecture (CUDA) of nVidia devices. Simulations with more than one million particles on a single GPU card exhibit speedups of up to two orders of magnitude over using a single-core CPU. It is demonstrated that the code achieves different speedups with different CUDA-enabled GPUs. The numerical behaviour of the SPH code is validated with a standard benchmark test case of dam break flow impacting on an obstacle where good agreement with the experimental results is observed. Both the achieved speed-ups and the quantitative agreement with experiments suggest that CUDA-based GPU programming can be used in SPH methods with efficiency and reliability

Downscaling CMIP6 climate projections to classify the future offshore wind energy resource in the Spanish territorial waters

The Spanish government has established a Maritime Spatial Planning including areas for wind farms, with the aim of contributing up to 40% of European floating offshore wind power by 2030. Thus, it is crucial to assess the current and future offshore wind energy resource in these areas, and classify the near future resource by considering wind power density and other relevant factors like resource stability, environmental risks, and installation costs. To attain the necessary high spatial resolution, a dynamic downscaling of a multi-model ensemble from the 6th phase of the Coupled Model Intercomparison Project was conducted using the Weather Research and Forecasting model in Spanish territorial waters, including the Iberian Peninsula, Balearic Islands, and Canary Islands. Future projections were considered under the Shared Socioeconomic Pathways 2–4.5 and 5–8.5 scenarios. According to the results, Spain’s offshore wind energy potential is projected to grow in the upcoming years, particularly in the Atlantic Ocean and surrounding the Canary Islands. Wind resource classification in the potential offshore wind farm areas reveals noteworthy diversity, with ratings ranging from “fair” (3/7) to “outstanding” (6/7). The most promising areas for offshore wind farm development in the near future are located in the northwest of the Iberian Peninsula and the Canary Islands.Xunta de Galicia | Ref. ED431C 2021/44Agencia Estatal de Investigación | Ref. TED2021-129479A-I00Agencia Estatal de Investigación | Ref. PID2021-128510OB-I00Agencia Estatal de Investigación | Ref. IJC2020-043745-

Integration of UAV photogrammetry and SPH modelling of fluids to study runoff on real terrains

Roads can experience runoff problems due to the intense rain discharge associated to severe storms. Two advanced tools are combined to analyse the interaction of complex water flows with real terrains. UAV (Unmanned Aerial Vehicle) photogrammetry is employed to obtain accurate topographic information on small areas, typically on the order of a few hectares. The Smoothed Particle Hydrodynamics (SPH) technique is applied by means of the DualSPHysics model to compute the trajectory of the water flow during extreme rain events. The use of engineering solutions to palliate flood events is also analysed. The study case simulates how the collected water can flow into a close road and how precautionary measures can be effective to drain water under extreme conditions. The amount of water arriving at the road is calculated under different protection scenarios and the efficiency of a ditch is observed to decrease when sedimentation reduces its depth.Ministerio de Economía y Competitividad | Ref. BIA2012-38676- C03-0

Efficiency and survivability analysis of a point-absorber wave energy converter using DualSPHysics

Smoothed Particle Hydrodynamics (SPH) method is used here to simulate a heaving point-absorber with a Power Take-Off system (PTO). The SPH-based code DualSPHysics is first validated with experimental data of regular waves interacting with the point-absorber. Comparison between the numerical and experimental heave displacement and velocity of the device show a good agreement for a given regular wave condition and different configurations of the PTO system. The validated numerical tool is then employed to investigate the efficiency of the proposed system. The efficiency, which is defined here as the ratio between the power absorbed by the point-absorber and its theoretical maximum, is obtained for different wave conditions and several arrangements of the PTO. Finally, the effects of highly energetic sea states on the buoy are examined through alternative configurations of the initial system. A survivability study is performed by computing the horizontal and vertical forces exerted by focused waves on the wave energy converter (WEC). The yield criterion is used to determine that submerging the heaving buoy at a certain depth is the most effective strategy to reduce the loads acting on the WEC and its structure, while keeping the WEC floating at still water level is the worst-case scenario.Agencia Estatal de Investigación | Ref. ENE2016-75074-C2-1-RAgencia Estatal de Investigación | Ref. IJCI-2017-32592Xunta de Galicia | Ref. ED431C 2017/6