Wave Surge Research Articles

Three-dimensional geomechanics experimental investigation on potential impulse waves generated by Wangjiashan landslide in Baihetan Reservoir, China

Landslides and the associated secondary disasters in reservoir areas are typically abrupt and catastrophic in nature. To address this challenge, prototype physical model experiments have been demonstrated to be effective tools for simulating these geological disasters. Following the impoundment of the Baihetan Hydroelectric Reservoir on the Jinsha River, the deformation and damage to the Wangjiashan (WJS) landslide intensified significantly. The Xiangbiling (XBL) residential area, along with the surrounding villages on the opposite bank, faces a significant risk of surge waves. This study, based on the WJS landslide, constructed a large-scale three-dimensional physical model (at a 1:150 scale) that integrates landslide, river, and residential area interactions. The model dimensions are 65 × 40 × 3 m3. Physical model experiments on landslide-generated surge waves were conducted under the conditions of an 825 m water level and seismic activity to explore the temporal and spatial evolution of the entire life cycle of the surge waves from the WJS landslide. Experimental results indicate that the XBL residential area was completely submerged under the wave impact. To mitigate the risk of surge wave disasters, the study proposed controlling surge wave size as an indicator for assessing landslide surge wave risk prevention and control. Through slope reduction and load-reduction engineering measures, the threat in the 4.5 km stretch of the reservoir's upstream and downstream channels was eliminated. The findings provide crucial experimental data and theoretical support for understanding the physical mechanisms underlying landslide-generated surge waves, as well as for early warning and disaster prevention.

Simulation of dynamic response changes in curved river flow under landslide-induced surge wave influence

This article uses a three-dimensional loose rock landslide surge model test in shallow water areas under dynamic water conditions to study the dynamic response characteristics of river flow. Based on the observation of the changes in the flow field and morphology of the river surface before and after the landslide body enters the water using a large-scale surface flow field measurement system, the changes in the river flow conditions under the influence of landslide surges are divided into four main stages: normal water flow state, landslide inflow disturbance state, wave current coupling motion state, and accumulation body ejection state. According to the acoustic Doppler velocimeter flowmeter arranged at the intersection of the initial surge waveform centerline and the mainstream flow direction, the three-dimensional velocity time-domain process near the water surface is measured and analyzed. Based on different cross sections and measuring points in the landslide area and its upstream and downstream, a non-steady flow propeller flowmeter and an ultrasonic wave/water level acquisition analyzer were arranged to measure and reveal the longitudinal and transverse flow velocity distribution and water surface line variation of the river under the influence of landslide surge.

Numerical Simulation Study on Dominant Factors of Surge Hazards in Semi-Submerged Landslides

Landslide-generated surge waves are significant natural hazards, posing severe risks to engineering safety. Despite extensive research on the dynamics of landslide-generated waves, studies analyzing controlling factors and their mechanisms remain limited, leaving key influencing processes inadequately understood. This study utilizes computational fluid dynamics (CFD) to perform a numerical simulation of a semi-submerged landslide in a hydropower station reservoir area. The research systematically investigated the effects of key variables, including slide volume, velocity, centroid height, and water depth, on the behavior of semi-submerged landslide-generated surge waves. Results demonstrate a positive correlation of slide volume, velocity, and centroid height with the initial wave height and run-up on the opposing shoreline. However, the impact of water depth reveals a more complex pattern, exhibiting distinct surge characteristics in the near-field and far-field zones. Via correlation and sensitivity analyses, this study elucidated the relationships between these factors and surge dynamics, identifying the primary factors influencing the size of the semi-submerged landslide-generated surge. The findings provide critical insights for predicting and mitigating surge disasters, offering both theoretical foundations and practical application value for landslide disaster prevention and management.

Multi-scale concurrent design of a 100 kW wave energy converter

Wave energy converters (WEC) are complex systems comprising multiple subsystems including wave capture structure and station keeping, power takeoff (PTO), and control. Designing the whole WEC system requires an effective design approach that considers mutual couplings among them throughout the entire design process. Moreover, the traditional serial design approach, transitioning from small-scale to full-scale designs incrementally, often overlooks issues related to scaling factors. This can lead to unexpected challenges and delays towards real ocean deployment. To address system-level considerations and scaling challenges in WEC design, this study introduces a novel multi-scale concurrent design approach. It facilitates full-scale WEC design from the early concept to ocean test planning. This approach ensures a holistic and effective design process that considers interactions among subsystems at each design stage and incorporates control co-design starting with early concept development. To demonstrate the presented approach, we introduce a case study focused on the design of a 100 kW floating oscillating surge wave energy converter (FOSWEC) for PacWave South ocean test site. This includes the design of wave capture structure and station keeping, PTO, control, ocean test planning, and techno-economic analysis. The case study showcases the effectiveness of the proposed approach, offering invaluable guidance and insights for future WEC development and support efficient, cost-effective collaboration in WEC design and testing.

3D WCSPH modelling of landslide-water dynamics during 1963 Vajont disaster

This study illustrates the full-scale 3D numerical simulation of the coupled water-landslide dynamics of the 1963 Vajont catastrophic event. The focus is given to the early phase of the event when about 270 million cubic meters of rock fell into the reservoir within an estimated runout time of about 25 s. A complex surge wave system developed throughout the basin in the first 40–55 s, producing maximum run-up of 270 m above the dam crowning. The mesh-free Lagrangian Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) method is adopted to discretize and solve the coupled system of governing equations for the landslide and water dynamics. The adopted model, which is based on SPHERA v.9.0.0 (Amicarelli et al. Comput Phys Commun, 2020), has been derived by introducing relevant modifications in the research code SPHERA (RSE SpA). The derived model is validated and the influence of water saturated soil on prediction of surge wave run-up is analysed. The average values from technical literature are assigned to mechanical parameters without tuning or calibration. The maximum flooding on the opposite side of the valley and the peak flow rate of the discharge hydrograph through the dam section show good agreement with reference data and improvements with respect to published results. The validated derived model proves to be a promising engineering tool for quantifying the level of risk in analogous applications.

Simple Method to Introduce Artificial Damping in Oscillating Surge Wave Energy Converters under Regular Waves Considering Viscous Effects

Simple Method to Introduce Artificial Damping in Oscillating Surge Wave Energy Converters under Regular Waves Considering Viscous Effects

Wave–Tide–Surge Interaction Modulates Storm Waves in the Bohai Sea

Typhoons, extratropical cyclones, and cold fronts cause strong winds leading to storm surges and waves in the Bohai Sea. A wave–flow coupled numerical model is established for storm events observed in 2022 caused by three weather systems, to investigate how storm waves are modulated by wave–tide–surge interaction (WTSI). Wave response is basically controlled by water level change in coastal areas, where bottom friction or breaking dominates the energy dissipation, and determined by the current field in deep water by altering whitecapping. Wave height increases/decreases are induced by positive/negative water level or obtuse/acute wave–current interaction angle, leading to six types of field patterns for significant wave height (Hs) responses. For the three storm events, Hs basically changed within ±5% in central deep water, while the maximum increase/decrease reached 160%/−60% in the coastal area of Laizhou Bay/Liaodong Bay. Based on maximum Hs and its occurrence time, WTSI modulation is manifested as the superposition effect of wave–tide and wave–surge interactions in both space and time scales, and occurrence time depends more on tide than surge for all three storms. The enhancement/abatement of WTSI modulation happens for consistent/opposite changing trends of wave–tide and wave–surge interaction, with the ultimate result showing the side with a higher effect.

Defining and Mitigating Flow Instabilities in Open Channels Subjected to Hydropower Operation: Formulations and Experiments

A thorough literature review was conducted on the effects of free surface oscillation in open channels, highlighting the risks of the occurrence of positive and negative surge waves that can lead to overtopping. Experimental analyses were developed to focus on the instability of the flow due to constrictions, gate blockages, and the start-up and shutdown of hydropower plants. A forebay at the downstream end of a tunnel or canal provides the right conditions for the penstock inlet and regulates the temporary demand of the turbines. In tests with a flow of 60 to 100 m3/h, the effects of a gradually and rapidly varying flow in the free surface profile were analyzed. The specific energy and total momentum are used in the mathematical characterization of the boundaries along the free surface water profile. A sudden turbine stoppage or a sudden gate or valve closure can lead to hydraulic drilling and overtopping of the infrastructure wall. At the same time, a PID controller, if programmed appropriately, can reduce flooding by 20–40%. Flooding is limited to 0.8 m from an initial amplitude of 2 m, with a dissipation wave time of between 25 and 5 s, depending on the flow conditions and the parameters of the PID characteristics.

Comparative analysis of hydrodynamic loads on bridge piers: assessing standards through numerical modeling

Currently, there is an alarming difference in the estimated actions on piers resulting from flash-floods and tsunamis as prescribed by international structural design codes. Previous studies have explored the interaction between surge waves and piers from a fluid-dynamics perspective, but there is no assessment about the relevance of the methods used in Structural Design to determine the hydrodynamic pressure resultants. To determine the degree of conservatism embedded in design, results from the different approaches are compared against validated numerical simulations. Three-dimensional numerical analyses were conducted using the OpenFOAM platform, employing the Large Eddy Simulation turbulence modeling approach to simulate the dam-break wave impacting the pier. The findings revealed that the maximum force was not necessarily caused by the stream’s first strike and could be sustained over time. The hydrodynamic pressure center consistently occurred at two-thirds of the stream depth, significantly impacting the overturning moments experienced by the pier. Identified inconsistencies between Codes underscore the need for revision of nonconservative approaches in predicting the design forces.

Case Study on the Adaptive Assessment of Floods Caused by Climate Change in Coastal Areas of the Republic of Korea

This study aims to assess the adaptability of coastal areas in the Republic of Korea to future climate change-induced flooding. Coastal areas can be susceptible to complex external factors, including rainfall, tide levels, storm surge wave overtopping, etc. The study employs an integrated approach to address this, connecting hydrological and marine engineering technologies. The models utilized in this study encompass XP-SWMM, ADCIRC, SWAN, and FLOW-3D. This study analyzed floods in 2050 and 2100, considering expected rainfall patterns, sea level rising, and an increase in typhoon intensity based on climate change scenarios for six coastal areas in the Republic of Korea. We reviewed the adaptability of flooding to climate change in each region.

What do trees reveal about the sliding of the lateral moraine of the Belvedere Glacier (western Italian Alps)?

The debris-covered Belvedere Glacier is an iconic place for investigating glacier dynamics and geomorphological processes typical of high mountain environments. Moreover, being located in an area highly suited to tourism, glacial and geomorphological hazards can evolve into risk scenarios. Particular attention has been paid during this research to the surge-type event that occurred at the beginning of the 21st century, and to the recent sliding of a lateral moraine nearby the chairlift station. Tree sampling was performed (19 trees on the lateral moraine; 10 undisturbed trees), and the results were compared with morphometric measurements on orthophotos of different years. Besides sampling trunks, the six available exposed roots (13 samples) from a tree located along the sliding niche were sampled to identify the exposure time. Morphometric measurements of the touristic trail dislocation indicate a sliding rate of 1.87 m/y – 1.98 m/y (2018–2023), while the regression rate of the sliding niche is 1.70 m/y (2021–2023). The age of trees along the trench is variable (14–49 years), as is the signal of compression wood, enhancing differentially the passage of the surge wave and the subsequent glacier downwasting. The beginning of root exposure occurred between 2017 and 2019, before the effective evidence of large fractures in the ground. Moreover, the roots show traumatic resin ducts in the period between 2020 and 2022, confirming the tree disturbance. In conclusion, the investigated events are recorded differentially in the sampled trees, especially in roots, anticipating the actual commencement of ground failure. A multidisciplinary approach, including remote sensing, field survey, and dendrogeomorphological analysis is essential to define the dynamics of complex systems.

Energy coupling and surge wave superposition of upstream series double surge tanks of pumped storage power station

Pumped storage power station with surge tank is common, and surge wave superposition can cause more dangerous water levels. This paper aims to study the energy coupling and surge wave superposition of upstream series double surge tanks of pumped storage power station. Firstly, the simulation model of pumped storage power station based on method of characteristics is established. Combined operating conditions are illuminated. Then, surge wave control strategies coupling gravitational search algorithm, relative objective proximity and marginal analysis principle are designed. Coupling control domains are determined to perform surge wave superposition analyses under single objective and multi-objective. Finally, the energy coupling and conversion mechanisms are revealed. The results show that the coupling control domains of combined operating conditions with same initial operating condition are the same. Control domains for undamped and damped systems contain two and three sub control domains, respectively. Based on energy conversion mechanisms between discharges and water levels, the number of discharge superposition points of pipelines affects energy coupling strength by changing coupling oscillations of water levels in surge tanks, which is related to the pipeline parameters, surge tank parameters and system damping. Energy coupling affects surge wave superposition by changing the actual control water level.

Numerical simulation on the prevention and control of landslide-induced wave disasters in Wangjiashan landslide area of Baihetan reservoir

The risk management of landslide surges after water storage in large reservoirs is a major challenge in reservoir management. The water storage in the reservoir area of the Baihetan hydropower station on the Jinsha River brings the potential of Wangjiashan landslide activation. This paper proposes a mitigation measurement based on slope cutting for the Wangjiashan landslide and evaluates the feasibility and effectiveness of the management scheme through numerical simulation. Results indicate that when water storage is in a normal level, after an earthquake, the landslide will impact the Baihetan Reservoir with a maximum velocity of 8.52 m/s, generating waves with a maximum wave height of 15.63 m. By removing the upper part of the landslide, the volume of the landslide is reduced from 611 × 10 4 m 3 to 369 × 10 4 m 3 , it will cut down the maximum wave height in the Xiangbiling residential area to 3.09 m, which significantly reduces the risk of landslide surge waves. It further establishes a disaster prevention and control plan for the landslide-induced wave disaster. Overall, this study provides important theoretical and practical references for the risk management of landslide surge waves and offers valuable insights for addressing similar issues in the future.

Association Between Hospital Type and Resilience During COVID-19 Caseload Stress : A Retrospective Cohort Study.

Imbalances between hospital caseload and care resources that strained U.S. hospitals during the pandemic have persisted after the pandemic amid ongoing staff shortages. Understanding which hospital types were more resilient to pandemic overcrowding-related excess deaths may prioritize patient safety during future crises. To determine whether hospital type classified by capabilities and resources (that is, extracorporeal membrane oxygenation [ECMO] capability, multiplicity of intensive care unit [ICU] types, and large or small hospital) influenced COVID-19 volume-outcome relationships during Delta wave surges. Retrospective cohort study. 620 U.S. hospitals in the PINC AI Healthcare Database. Adult inpatients with COVID-19 admitted July to November 2021. Hospital-months were ranked by previously validated surge index (severity-weighted COVID-19 inpatient caseload relative to hospital bed capacity) percentiles. Hierarchical models were used to evaluate the effect of log-transformed surge index on the marginally adjusted probability of in-hospital mortality or discharge to hospice. Effect modification was assessed for by 4 mutually exclusive hospital types. Among 620 hospitals recording 223 380 inpatients with COVID-19 during the Delta wave, there were 208 ECMO-capable, 216 multi-ICU, 36 large (≥200 beds) single-ICU, and 160 small (<200 beds) single-ICU hospitals. Overall, 50 752 (23%) patients required admission to the ICU, and 34 274 (15.3%) died. The marginally adjusted probability for mortality was 5.51% (95% CI, 4.53% to 6.50%) per unit increase in the log surge index (strain attributable mortality = 7375 [CI, 5936 to 8813] or 1 in 5 COVID-19 deaths). The test for interaction showed no difference (P = 0.32) in log surge index-mortality relationship across 4 hospital types. Results were consistent after excluding transferred patients, restricting to patients with acute respiratory failure and mechanical ventilation, and using alternative strain metrics. Residual confounding. Comparably detrimental relationships between COVID-19 caseload and survival were seen across all hospital types, including highly advanced centers, and well beyond the pandemic's learning curve. These lessons from the pandemic heighten the need to minimize caseload surges and their effects across all hospital types during public health and staffing crises. Intramural Research Program of the National Institutes of Health Clinical Center.

Numerical study on hydrodynamic interaction between two parallel surge-released ships advancing in head regular waves based on the hybrid method

This study examines the hydrodynamic interaction between two parallel surge-released ships in head regular waves. A hybrid approach combining potential flow theory and functional-decomposition URANS is used for an efficient and accurate simulation. The methodology involves a surge-released module, 4DOF motion equations, multiple coordinate systems, and a dynamic structured grid. Two ship models are used for validation, comparing numerical and experimental results in ship motions and wave loads. The analysis shows good agreement, with differences of less than 5 % in heave and pitch motions, less than 8 % in roll motions, and less than 15 % in total resistance and sway interference forces. Present study also observes consistent trajectories of the wave system between the two ships. The influence of surge motion and wave height on wave-ship-ship interaction is investigated, emphasizing the importance of considering surge motion in seakeeping performance and longitudinal separation. The occurrence of parametric roll in Ship B is accurately resolved by the hybrid method and the parametric roll amplitude is smaller under ship-to-ship interaction conditions. Wave-induced moments play a limited role in this phenomenon, while the dominating roll restoring moment exhibits a hardening effect. Accordingly, roll motion and moments remain relatively unchanged with increasing wave height, indicating the strong nonlinear nature of parametric roll.

Hazard assessment of dynamic marine processes during two extreme weather systems near the Shandong Peninsula

Typhoons and extratropical cyclones both occurred frequently on the Shandong Peninsula and have induced severe dynamic marine disasters. In this study, the typhoons and extratropical cyclones that occurred from 1979 to 2018 were counted and classified according to their tracks. We simulated the storm surge and disastrous waves using a coupled ocean-wave model and assessed the hazard distribution under different types of typhoons and extratropical cyclones. Through comparison, it was found that the southern Yellow Sea steering type typhoons and Yangtze-Huai cyclones occurred most frequently and were most likely to cause disasters. Regarding the hazard posed by the storm surge, there was a clear demarcation between the northern and southern coasts of the peninsula, as well as between the eastern and western coasts. The western coast of the peninsula was more exposed to storm surges induced by typhoons, while the northern coast of the peninsula was more exposed to storm surges induced by extratropical cyclones. The hazard posed by waves exhibited a localized characteristic. The wave hazard was the greatest near the peninsula cape and the lowest surrounding the Laizhou Bay, which was contrary to the distribution of the storm surge hazard. The identification of key management areas for disasters provides basic data and a technical reference for coastal development planning and can play a positive role in disaster prevention.

Application of SPH in rheology model for the submerged landslide

The seafloor environment is prone to rapid changes caused by landslides, which can result in significant human, financial, and environmental consequences. Previous research efforts have primarily focused on studying rigid submerged landslides using physical experiments and mesh-based numerical simulations. However, there is a need to investigate deformable soil masses due to their inherent complexity. In the current study, a smoothed particle hydrodynamics (SPH) method was developed to examine the behavior of submerged landslides. Three rheological models, namely Bingham, Herschel–Bulkley (H–B), and μ(I), were applied to characterize the properties of the sediment materials. The SPH governing equations were modified at the interface between the water and sediment phases to account for the density discontinuity between them. The viscosity term at this interface was determined using the Owens equation. The effective pressure, a crucial parameter in rheological models, was appropriately modified to reflect the influence of the water column on the sediment particles, utilizing a simple algorithm. For the μ(I) rheology, separate equations were applied to describe the behavior of dry and saturated conditions. Additionally, the Mohr–Coulomb criteria were utilized in the Bingham and H–B models to determine the yield stress. To validate the effectiveness of the proposed modeling approach, a column failure scenario was first simulated. Subsequently, a rigid submerged landslide was investigated to assess the capability and validity of the proposed framework in accurately capturing surge wave generation and calibrating the boundary friction factor. Finally, two deformable submerged landslides involving different materials, namely sand and glass beads, were simulated and compared with previous experimental and numerical studies at different time steps. Through these comprehensive investigations, the current understanding of the complex behavior exhibited by submerged landslides is enhanced, and valuable insight into landslide dynamics is provided.

Modeling, system identification, and friction compensation of an actuator system for heave and surge wave energy converter experiments

Modeling, system identification, and friction compensation of an actuator system for heave and surge wave energy converter experiments

Benchmarking Physical Model Experiments with Numerical Simulations for the Wangjiashan Landslide-Induced Surge Waves in the Baihetan Reservoir Area

The Baihetan Hydropower Station reservoir area began impoundment in 2021, triggering the reactivation of ancient landslides and the formation of new ones. This not only caused direct landslide disasters but also significantly increased the likelihood of secondary surge wave disasters. This study takes the Wangjiashan (WJS) landslide in the Baihetan reservoir area as an example and conducts large-scale three-dimensional physical model experiments. Based on the results of the physical model experiments, numerical simulation is used as a comparative verification tool. The results show that the numerical simulation method effectively reproduces the formation and propagation process of the WJS landslide-induced surge waves observed in the physical experiments. At the impoundment water level of 825 m, the surge waves generated by the WJS landslide pose potential threats to the Xiangbiling (XBL) residential area. In this study, the numerical simulation based on computational fluid dynamics confirmed the actual propagation forms of the surge waves, aligning well with the results of the physical experiments at a microscopic scale. However, at a macroscopic scale, there is some discrepancy between the numerical simulation results and the physical experiment outcomes, with a maximum error of 25%, primarily stemming from the three-dimensional numerical source model. This study emphasizes the critical role of physical model experiments in understanding and mitigating surge wave disasters in China. Furthermore, physical experiments remain crucial for accurate disaster prediction and mitigation strategies. The theories and methods used in this study will provide important references for future research related to landslide disasters in reservoir areas.

Oscillating surge wave energy converter using a novel above-water power takeoff with belt-arc speed amplification

We investigate the performance of a novel power takeoff (PTO) featuring belt-arc speed amplification for oscillating surge wave energy converters (OSWECs), aiming to address the PTO design challenges of extremely low rotary speed and large torque under the low-frequency and large energy density ocean wave excitations. The belt-arc design significantly increases the rotary speed of the generator, enabling generator downsizing and decreasing the powertrain friction losses. The design also allows for placing the generator above water, eliminating the need for high Ingress Protection ratings for the generator and powertrain, and potentially leading to substantial reductions in capital and maintenance costs. Using the potential flow theory, the dynamics of the integrated system are analyzed, and key parameters are identified. To validate the numerical analysis, a 1:10 scale model is designed, fabricated, and tested in a wave tank. Performance evaluations are conducted under regular and irregular wave conditions, with quantified effects of parameter tuning. The results reveal an optimal wave-to-electric efficiency of 48% under regular wave excitation and 20% under irregular excitation. These findings underscore the effectiveness of the proposed novel PTO design in addressing the challenges of low rotation speed and large torque inherent in OSWECs, demonstrating its ability to efficiently convert wave power into electricity.