Hydrodynamic Impact Research Articles

Assessing hydrodynamic impacts of tidal range energy impoundments in UK coastal waters

Tidal range energy comprises a vast theoretical resource of 9,220 TWh per year, globally, with advantageous characteristics of predictability, generation flexibility and reliability. Approximately 13% of this resource lies within the United Kingdom’s (UK) coastal waters, where it could supply up to 12% of annual electricity demand. Tidal range energy conversion traditionally involves constructing and operating large-scale coastal or offshore impoundments (O10-100 km2), which will redefine near and far-field water levels and flow patterns. The relationship between the scale of the impoundment area and hydrodynamic impact has not been investigated for UK sites. To address this, we develop a two-dimensional (depth-averaged) TELEMAC model of the Irish Sea, and simulate six scenarios involving tidal range schemes of increasing basin area, from 25 to 150 km2, located on the North Wales coast in an open coastal basin setting. Results indicate that far-field (30−150 km) changes to the amplitude of the semi-diurnal (M2) tidal constituent exhibit a linear relationship with impoundment area and volume (correlation coefficient R=0.95 and R=0.96, respectively). The largest impoundment (150 km2) caused far-field changes in maximum surface elevation (2<ηmax<3 cm); near-field surface elevation was reduced (ηmax>3 cm).

Assessment of daily altimeter-based open ocean water level with hindcast and forecast efficiency

Satellite altimetry water level measurements are valuable in episodic and climate change related hydrodynamic impact studies, despite their sparse temporal distribution over the global ocean. This study presents the spatiotemporal characteristics of the open-ocean satellite derived water level measurements globally for the period 31/12/1992-15/10/2019 and evaluates their efficacy to represent the water level even during intense atmospheric conditions. Water level measurements from 23 different satellite missions are compared with tide gauge records and hydrodynamic simulations. The satellite measurements reproduce the water-level variations with good to excellent skill for ~60% of the areas considered. Additionally, satellite measurements and local atmospheric conditions are utilized in order to examine whether statistical data driven models can contribute to decreasing the temporal sparseness of the water level data over the global ocean. The suitability of this low computational-cost method is demonstrated by deriving a 63-year hindcast of the daily maximum water level for the global ocean, and for a medium-term 15-day ensemble forecast. The publicly available long-term water-level hindcast and the parameters of the data-driven statistical model derived can serve as a tool for designing and facilitating local and global coastal risk-assessment studies.

Role of Underlying Substrates on the Interfacial Thermal Transport in Supported Graphene Nanochannels: Implications of Thermal Translucency.

We study the role of underlying substrates on interfacial heat transfer within supported graphene nanochannels. Due to graphene's translucency, the underlying substrate, apart from its known hydrodynamic impact on fluid flow, also influences heat transport. We introduce the term "thermal translucency" to describe this phenomenon in the context of interfacial heat transfer. Our findings reveal that the Kapitza resistance, RK, is dependent on the specific underlying substrate. The specific underlying substrate alters the water-graphene interface potential landscape due to graphene's translucency, leading to a breakdown in the inverse relationship between interfacial water density peaks and RK values, typically observed at water-graphene and water-graphite interfaces. Remarkably, higher interfacial water density peaks correlate with more ordered energy patterns, not necessarily tied to more hydrophilic substrates as the literature commonly suggests for lower RK values. The insights provided have implications for controlling and tuning thermal transport and heat storage in nanofluidic devices.

Hydrodynamic Impact of Dusty Fluid-Suspended Solid Particles in a Single-Walled Corrugated Channel for Water-Curing Infrastructure Networks

Infrastructure engineering is impacted by solid particles in fluids, and engineering components are influenced by fluid flow methods. This work explores the effects of dusty fluids with suspended solid particles in a single-walled corrugated channel using electromagnetic hydrodynamics. Potential, continuity, and momentum equations were employed to study the periodic sinusoidal waves in the corrugations of two wavy walls using the perturbation method. We assessed the impact of corrugation on velocity for EMHD fluid flow using mathematical computation, concentrating on the analytical velocity solutions. The analysis of velocity profiles through graphs reveals that corrugation affects fluid and particle velocity behavior, with small amplitude reducing wave effects and dusty particles boosting velocity. The proposed model uses mathematical induction to solve engineering problems using corrugated wall conditions for fluid control during curing stages. It may be valuable for sanitation networks, rainwater drainage networks, and irrigation systems. In the end, a thorough examination of the obtained results and information from past papers demonstrated a high level of agreement. Additionally, its use in the curing of water will offer alternative methods of managing the flowing fluid than mechanical pressure.

Hydrodynamic impact as a way of controlling the state of the coal-gas system: analysis and data processing

The research results on hydrodynamic impact during the outburst-hazardous coal seams opening at the Donbas Central District mines are considered. Emphasis is placed on the technological processes complexity related to coal mining and the importance of systematic monitoring of the stress-strain state of rock massif. It is noted that the research and optimization of the hydrodynamic impact process parameters and the coal-gas system state require the use of statistical and probabilistic methods, in particular descriptive statistics. An analysis of the hydrodynamic impact process parameters on the stress-strain state of rock massif in the conditions of steeply sloping seams was carried out using the example of 50 openings. A data array with different characteristics and parameters distribution was obtained. Methods of data distribution normality checking and their use in normality hypothesis verifying for process control are considered. Information on research methods and analysis of parameters related to hydrodynamic impact on the rock massif is summarized. The results of studies of hydrodynamic impact parameters and control of the gasdynamic state of outburst-hazardous coal seams during their opening are considered. The results will be used in further studies of the controlling process of stress-strain state of outburst-hazardous coal seams by hydrodynamic impact.

Numerical Simulation of Aluminum Plate Damage Subjected to Hydrodynamic Impact

This paper presents numerical modeling and simulation of damage that occurred to an aluminum plate due to a hydrodynamic impact. The model is developed based on a published experiment that was carried out by dropping a thin stiffened aluminum hollow box into the water from a prescribed height. The hydrodynamic impact causes damage in the middle of the plate which had an initial circular hole in the middle. The ABAQUS/CAE is used to model this experiment by using the Coupled Eulerian-Lagrangian method. The ductile damage property of the aluminum is defined to model the failure. The results show that the numerical simulation can predict the acceleration of the specimen close to that observed during the experiment. The simulation can also replicate the damage of the plate. A parametric study shows that one of the parameters that may affect the shape of the damage is the boundary condition definitions of the plate.

FIELD AND MODEL RESEARCH OF THE GROUNDWATER FLOWS IN THE AREA OF THE PAKS-2 NPP CONSTRUCTION, HUNGARY

The construction of the nuclear power plant (NPP) requires conducting a large number of engineering and hydrogeological surveys, as well as assessment of the design decisions’ safety. A deep excavation pit at the Paks II NPP construction site requires execution of the cut-off wall due to extremely high groundwater saturation of the alluvial deposits. However, lithological anisotropy and the presence of dislocation zones did not allow identifying the appropriate depth for the cut-off wall construction. Unfortunately, engineering geological boreholes with a 20-meter distance between them and surface and borehole geophysical surveys could not identify the hydrogeological units. Thus, to conceptualize the hydrogeological settings, an analysis of the groundwater head distribution and the large-scale pumping tests were conducted. The interpretation of the geological data and the distinguishing of the hydrogeological units were carried out iteratively using the hydrogeological numerical model. The flow model could represent the hydraulic head distribution, the response of the lithologically heterogeneous layers to the water fluctuations in the Danube river, and the pumping tests carried out at the different depths. The results of the hydrogeological modeling revealed the aquitard to be continuous throughout the territory; however, its top’s depth changes from 30–35 to 90 m within the construction site of the Paks II NPP. This complex geometry of the aquitard is controlled by the plicated dislocation zone, which cuts the construction site in half and is revealed as the right wall of the graben.Correct hydrogeological stratification enabled us to ensure waterproof activities such as the cut-off wall construction using the hydrogeological model when excavating a deep pit for the Paks II NPP. This also minimizes the hydrodynamic impact on the closely located NPP Paks in operation.

Automatic classification of biofouling images from offshore renewable energy structures using deep learning

Offshore Renewable Energy (ORE) is developing worldwide, for which biofouling is a crucial parameter to consider, both for engineering and environmental monitoring purposes. In this study, machine learning tools are used to classify macro-biocolonisation images into four categories: 'mussels', 'barnacles', ‘calcareous worms' and ‘no macro-biocolonisation’ as part of the suspected “most impacting species” of the fluid/Structure behavior of colonized components. A transfer learning approach is investigated using a state-of-the-art convolution neural network (CNN) architecture and an open-source training algorithm is specifically modified to ensure rapid reproducibility of the methodology: image selection, CNN adaptation, training/validation process and quality assessment. A database of 1261 images is set up to train the models; their performances are tested using images of offshore components with and without biocolonisation. Two stochasticity sources were evaluated: coming from the modest size of the data base trough cross validation on 5 folds, and sensitivity to the numerical model through the building of 30 models per fold. The performance was discussed with particular care, given the small number of images available and the statistical uncertainties of the metrics evaluated from the validation process. The average performance of the models on the testing images is 69% of good detection for all classes combined. In engineering point of view the results are satisfactory since the two classes with maximum hydrodynamic impact (mussel and ‘no macro-biocolonisation’) provides average detection of 81% and 79%. Recommendations are proposed to enrich the training image database and photographic surveys on offshore structures, in providing metrics enabling algorithm optimization in engineering purposes. The main innovation of this study is to adapt existing machine learning tools to a new and complex application area: the biofouling.

Вероятностная оценка эффективности применения метода циклического заводнения нефтяных пластов

Extraction of hard-to-recover hydrocarbons is becoming an urgent task for the entire world oil community. The development of new technologies and methods, as well as the improvement of existing ones, have become the main issue in the extraction of hydrocarbons at existing fields. The aim of the work was to develop the technology of hydrodynamic impact on the hydrocarbon deposit. The process of oil reservoirs flooding is one of the most widespread and traditional in the application of extraction of hard–to-recover oil. The most effective in terms of impact is the cyclic regime of flooding of oil reservoirs – periodic changes in fluid flow rates at injection and production wells with a phase shift of oscillations for individual groups of wells. The use of cyclic flooding in combination with an increase in the average level of injection pressures can give a significant increase in the coefficient of reservoir coverage in power. The degree of hydrodynamic connectivity of the layers along the section has a significant impact on the effectiveness of cyclic flooding. The coefficient of lithological connectivity of formations is determined by the ratio of the area of the reservoir confluence to the total area of the deposit and can characterize the hydrodynamic connectivity of formations along the section. Using the example of the D3 of the Korotkoye field, an assessment of the start-up of the wells of the PPD system was done as well as the analysis of the nature of its influence on the volume and water content of the extracted products of the D3 formation of the Korotkoye field under various injection modes using cyclic flooding. It is determined that when both injection wells are stopped for a long period, the output of the produced products decreases to 25%. The analysis of the total oil flow rate showed that in the variants with well shutdowns there is a stronger decrease in oil flow rate than in the variants with cyclic injection, in the variants with cyclic operation of the PPD system the highest indicators of accumulated oil production are achieved for a certain period.

Dynamic Performance of Suspended Pipelines with Permeable Wrappers under Solitary Waves

Submarine pipelines are widely adopted around the world for transporting oil and gas from offshore fields. They tend to be severely ruined by the extreme waves induced by the natural disaster, such as hurricanes and tsunamis. To maintain the safety and function integrity of the pipelines, porous media have been used to wrap them from the external loads by the submarine environment. The functions of the porous wrappers under the hydrodynamic impact remain to be uncovered before they are widely accepted by the industry. In this study, a numerical wave tank is established with the immersed boundary method as one of the computational fluid dynamics. The submarine pipelines and their porous wrappers are two-way-coupled in terms of displacement and pressure at their interfaces. The impact from the solitary waves, which approximately represent the extreme waves in the reality, on the pipelines with different configurations of the porous wrapper is investigated. The results present significant protective functions of the wrappers on the internal pipelines, transferring the impact forces from the pipelines to the wrappers. The protective effects tend to be enhanced by the porosity and thickness of the wrappers. The influence of the pipeline configurations and the marine environment are then analysed. As for the front pipeline, an increase in the gap leads to a slight increase in the horizontal forces on both the wrapper and the pipeline, but a significant increase in the vertical forces. As for the rear pipeline, because of the shield function of the front pipeline, the velocity within the gap space and the forces on the pipes are decreased with the decrease in the gap size. The complex flow fields around the pipelines with wrappers are also illuminated, implying that the protection function of the wrapper is enhanced by the wave height reduction.

Assessing the Effects of Miedzyodrze Area Revitalization on Estuarine Flows in the Odra River

The estuarine section of the Odra River network is influenced by various phenomena that shape its hydrological regime. The Lower Odra region includes “Miedzyodrze,” an area between the main branches of the Odra River that was previously used for agriculture. However, due to a lack of maintenance in the 20th century, Miedzyodrze’s infrastructure suffered significant damage, resulting in blockages and channel shallowing. Previous models of the lower Odra River network overlooked Miedzyodrze’s hydrodynamic impact on flow. To address this, a study aimed to assess Miedzyodrze’s influence on flows within the network. Three computational scenarios were developed: one treating Miedzyodrze as an uncontrolled floodplain, another excluding it from the flow like past models, and a third incorporating the hydraulic capacity of selected Miedzyodrze channels with hypothetical restoration. The construction of the models involved extensive field research, including bathymetric surveys and an inventory of channels and structures. Challenges arose from legal and technical constraints during the research. The hydraulic network model was developed using Hec-Ras software and underwent calibration and verification processes for accuracy and reliability. The study focused on analyzing changes in water distribution, flow reduction along the East Odra, flow ratios at specific points, and downstream flow alterations based on different scenarios and the aperture extent of the Widuchowa weir. The conducted analyses and deductions validate the thesis proposed in this study that the potential process of channel dredging and renovation of the hydraulic infrastructure in Miedzyodrze will significantly influence the flow distribution within the lower Odra River network. The significant impact of the Międzyodrze area on water distribution in the lower course of the Odra River has been successfully demonstrated. Under specific hydrological scenarios, a potential increase in flow through the Międzyodrze area from approximately 10–100 m3/s to a range of 60–420 m3/s has been identified. This dynamic alteration of river flow exerts a pronounced influence on further water distribution within the entire river network. For the purpose of addressing the matter at hand within this study, the following procedures were undertaken: → analysis of characteristic flow regimes and states, → bathymetric measurements, → flow measurements at selected cross-sections, → construction of a numerical model of the river network, → model calibration, → formulation of a set of boundary conditions, → modeling, → results analysis.

The Hydrodynamic Impact of the South-to-North Water Diversion Project on the Lower-reach Lake of Nansi Lake

In order to study the changes in hydrodynamic characteristics of the lower-reach lake of Nansi Lake, this paper established a two-dimensional hydrodynamic model of the lower-reach lake of Nansi Lake based on topography, like rainfall, evaporation, and wind field of the lower-reach lake of Nansi Lake, and carried out water level verification, which is representative and can reflect the process of water level and flow velocity changes of the lower-reach lake of Nansi Lake before and after the South-to-North Water Transfer. The model results show that, before the Nansi Lake was connected to water, the lake area of Zhaoyang Lake in the north was long and narrow and the water level was high. The overall flow velocity of Weishan Lake was low, and the stagnant water area and low flow velocity area accounted for a large proportion. After the opening of the southern four lakes, the high-water level area is concentrated in the wide Weishan Lake area, the water level in the Zhaoyang Lake area is reduced, and the changes between different water level gradients tend to be gentler, and the mobility of the water body is greatly improved.

Improvement and evaluation of hydrodynamic conditions in plain regional drainage systems by artificial lakes: a case study of Xinxiang Economic Development Zone, China.

With the development of the city, people pay more attention to the ecological construction of the city. The objective of this work was to study the effect of artificial lakes on hydrodynamic conditions in urban drainage systems. With Arcgis and the advantage of SWMM in analyzing the impact of the rainfall process on urban runoff, the urban flooding model of "pipe network + river network + artificial lake" was established in the study area. Two scenarios were set up with and without the presence of artificial lakes, and comparative analyses were conducted under the different intensities of rainfall (0.5a, 1a, 2a, 5a, 10a, 20a). The results show that under certain rainfall conditions, the presence of the artificial lake increases the peak flow and rate of upstream streams and decreases the flow and rate of downstream streams in the regional drainage system. The duration of the peak flow rate in the upstream channel increases, and the flow rate curve becomes flat during the confluence; the flow rate in the downstream section decreases, and the magnitude of the peak flow rate change decreases, and a more obvious horizontal section appears. The time of peak occurrence in the downstream river is earlier. The hydrodynamic impact on the downstream channel is more significant. The improvement of hydrodynamic conditions of the drainage system by the artificial lake helps to optimize the layout of low impact development (LID) measures in the study area and also guides ecological construction in other cities.

Hydro-structural response of complex elevated pile cap substructures to strom surge impact by smoothed particle hydrodynamics: Part 2: Model results

Extreme waves, i.e., tsunamis and storm surges, can generate tremendous hydraulic bores capable of inflicting considerable damage to near-shore bridge infrastructure, often leading to structural failure. The conventional numerical approach to studying hydrodynamic impact is based on Eulerian grid-based, e.g., finite volume or diffused element algorithms. These perform well with perfectly defined simulation domains. However, in case of severe surface deformation, these grids must be continually reconstructed, which is time-intensive and introduces cumulative system errors. As Smoothed Particle Hydrodynamic (SPH) integrates the hydrodynamic equations of motion on each particle in Lagrangian formalism, it can handle complex wave non-linearity without mesh constraints. In this study opensource DualSPHysics model is applied to study the hydrodynamic response and group effect of elevated pile cap substructures to impulsive surge impact. Two conventional grids (2 × 2, 2 × 3 array-layout) and a hexagonal pile arrangement under three submersion levels are considered in studying the pile group effect on hydrodynamic forcing mechanism, flow characteristics, and factors governing pressure variability. The uplift thrust on the pile cap was found to be dependent on the surge fluid mass, incident velocity, and vertical distance between the surge breaking point and cap bottom. At impulsive impact, gridded pile arrangement offered greater resistance to incident surge flow. In reference to free flow condition, hexagonal layout can reduce the average flow velocity by 8.22–19.76%, while for a gridded system, it is between 14.00% and 23.52% depending on the submersion level. However, in a quasi-steady state, the flow resistance of the hexagonal system was greater. The study also compared the numerical results to accepted offshore design standards, which were found to underestimate the pile's group effect, specifically for complex hexagonal layouts. Later, it proposes rationalized force diagrams to be applied in design of complex elevated structures. The paper's finding is expected to contribute to formulating new guidelines for resilient hydraulic design of coastal and deep-water elevated structures.

The large-scale impact of anthropogenic mixing by offshore wind turbine foundations in the shallow North Sea

Structure drag from offshore wind turbines and its physical impacts on the marine environment of the German Bight are investigated in this study. The flow past vertical cylinders, such as wind turbine foundations, and associated turbulent mixing has long been studied, but questions remain about anticipated regional implications of offshore wind infrastructure on physical and biogeochemical conditions. Here, we present two existing modeling approaches for simulating wind turbine foundation effects in regional ocean models and discuss the problematic use of very high resolution in hydrostatic modeling. By implementing a low-resolution structure drag parameterization in an unstructured-grid model, we demonstrate the impacts of monopile drag on hydrodynamic conditions, validated against recent in-situ measurements. Although the anthropogenic mixing is confined at wind farm sites, our simulations show that structure-induced mixing affects much larger, regional scales. The additional turbulence production emerges as the driving mechanism behind the monopile impacts, leading to changes in both the current velocities and stratification, with magnitudes of about 10%, similar in magnitude to regional annual and interannual variabilities. This study provides new insights into the hydrodynamic impact of offshore wind farms at their current development levels and emphasizes the need for further research in view of potential restructuring of the future coastal environment.

Study of the Jet Output Characteristics under Multi−Source Coupling

The challenges posed by elevated rock hardness, deficient drillability, excessive friction torque, and significant underpressure in extended−reach horizontal wells are the primary factors that contribute to low ROP (Rate of Penetration) and limited horizontal reach during the drilling operation. Reducing drag and friction is one of the primary methods of addressing the aforementioned challenges. To augment the pulse output characteristics of the oscillating jet and bolster the energy of the hydrodynamic impact load, we developed and designed a multi−source impact oscillation speed−increasing tool coupled with blade rotation disturbance and multi−order oscillation cavity self−excitation. We utilized fluid dynamics software to model and conduct numerical analysis on the multi−source pulsed jet generator. Furthermore, we constructed a prototype and subjected it to testing. This paper examines the impact of dimensionless structural parameters on the pressure output characteristics of the multi−source pulse−jet generator. Specifically, we used three dimensionless quantities (cavity length ratios, cavity diameter ratios, and inner wall collision angle ratios) to study this effect. The findings indicate that the multi−source impact oscillation speed−increasing tool is capable of augmenting the pulse oscillation amplitude, and the frequency of pulse oscillation can be adjusted within the range of 5 Hz to 15 Hz. During the study, we determined that the optimal oscillation output characteristics can be achieved when the cavity diameter ratio is 0.8, the cavity length ratio is 1.0, and the inner wall collision angle ratio is 1.5. These findings present a novel approach for the development of downhole hydraulic impact oscillation speed−increasing tools.

Analysis of fluid dynamic behavior and impact load on oblique water entry of a two-dimensional seaplane based on VOF method

Seaplane landing is a typical water entry impact phenomenon. However, our understanding on the development of jet flow and air cavity, and corresponding load characteristic is still limited. In this paper, the impact problem of oblique water entry of a two-dimensional seaplane is studied to clarify the relationship between theses complex flows and loads. A gas-liquid two-phase model is established to model these complex fluid flows, where the air-water interface is captured based on a VOF algorithm. The accuracy is validated by the published experimental data. Some hydrodynamic impact characteristics related to seaplane model under different oblique water entry postures, including air-water free surface and local impact pressure are discussed. Complicated flows (air cavity and jet flow impact) are the internal cause to some unusual load characteristics such as multiple pressure peaks, negative pressure, simultaneity of impact load on the airfoil, and great difference of load at different positions on the cabin. The evolution of jet flow and air cavity is further discussed through combing free surface and pressure distribution. Results clarified the mechanism of complex flows under the influence of bottom cabin and inclined postures, which will be helpful to further understand the impact phenomenon of seaplane landing.

Water tanks - checks of tensile internal forces in the walls of cylindrical tanks

The report examines parametric solutions of the facilities - by changing the elements of the load-bearing structure of reinforced concrete tanks. The created computational models have specialized software and seismic analysis included. The hydrodynamic impact of water during an earthquake taken into account. The annular efforts in the walls were checked to determine the double (symmetrical) reinforcement in the radial direction. Comparisons are given for the individual solutions. The construction of the wall has an effect on the internal forces. Envelope combinations of static and seismic impacts must be made to provide the elements for peak values not taken into account in the analysis.

ОБҐРУНТУВАННЯ ГЕОБЕЗПЕЧНИХ ТА ГЕОМЕХАНІЧНИХ ПАРАМЕТРІВ РОБО-ТИ ГІДРОТЕХНІЧНИХ СПОРУД, РЕГУЛЮВАННЯ СТОКУ ТА УПРАВЛІННЯ ВО-ДНИМИ РЕСУРСАМИ ШЛЯХОМ ГІДРОГЕОЛОГІЧНОГО МОДЕЛЮВАННЯ

Purpose. The purpose of this work is the development and verification of the adequacy of the methodology for assessing the hydrodynamic and geomechanical impact of various drainage and hydrotechnical structures on the environment over time, based on hydrogeological modeling, which allows to substantiate the geosafe parameters of their long-term operation and management of water resources. Methods. The proposed comprehensive approach includes: collection and analysis of geological and hydrogeological data on the research area; numerical modeling of hydrodynamic processes; solving inverse problems; execution of predictive calculations regarding changes in the level of groundwater under the influence of drainage and hydrotechnical structures; analytical calculations of subsidence of the earth’s surface caused by this. Findings. According to the results of solving the inverse problems, it was proved that the deviation of the calculated marks of the groundwater levels on the model from the actually established ones does not exceed 0.3 m with a value of the water balance imbalance of 0.001%, which confirms the adequacy of the model and the correctness of the task of filtration characteristics, external and internal hydrodynamic boundaries . The solution of model forecasting problems made it possible to establish that the construction of two ponds with an absolute water mark of 54.0 m and a horizontal drainage 600 m long with a level mark of 56-57 m in the studied area leads to a decrease in groundwater and the elimination of areas under -fillings with a depth of less than one meter. It has been established that with the lowering of the groundwater level caused by the work of hydraulic and drainage structures, the maximum possible subsidence of the soil is 1.5 cm, which does not exceed the allowable subsidence for all types of buildings. Originality. The methodology for assessing the hydrodynamic and geomechanical impact of drainage and hydrotechnical structures on the environment has been substantiated and verified. The proposed method makes it possible to quantitatively assess the hydrodynamic regime and geomechanical state of rocks during long-term operation of these structures in areas with a complex geological structure under the significant influence of natural and man-made factors. Practical implication. The proposed method can be used in the design of new hydrotechnical and drainage structures, as well as the evaluation of parameters of their geo-safe operation, which ensure flow regulation and prevention of flooding of territories.

Experimental study of the surge- and bore-induced impact pressure on a vertical wall and its foundation

Both surge and bore impacts could lead to the failure of coastal structures. Nevertheless, differences between the surge- and bore-induced hydrodynamic impact processes on a vertical wall are still unclear. Meanwhile, investigation of the bed pressure features during the wall impact is also rare. In this study, a series of dam-break experiments were conducted to specify the hydrodynamic characteristics of the surge and bore impact pressure on a vertical wall and its foundation. In the experiment, same initial water head was applied with five different initial downstream water levels (IDWLs). Temporal variations of the surge/bore impact pressures at four elevations on the wall and four positions along the bed were recorded. The surge induced maximum water height on the wall is larger than the bore-induced one, which decreases with the increase in the IDWL. With the increase in the IDWL, the initial peak impact pressure gradually decays owing to the slowing down of flow velocity and the significant air entrainment at the bore front. Regarding the initial peak pressure and its rise time, it is confirmed that the initial surge impact pressure is sensitive to the wall elevation, whereas it is relatively uniform along the wall bottom region for the bore impact pressure. As for the measured bed pressure, the initial impact zone induced by the secondary flow near the wall and the falling impact zone caused by the falling down of water mass from the splash-ups away from the wall are identified, showing different hydrodynamic features.