Force Of Water Flow Research Articles

Transport behavior of Polymeric Methyl Methacrylate nanoplastics in saturated and unsaturated porous media: Combined influence of electrolyte and organic acids

The migration behavior of Polymeric Methyl Methacrylate (PMMA) nanoplastics in saturated porous media and unsaturated porous media is investigated under conditions of electrolytes in combination with organic acids. In the saturated porous media, the mass recovery rate of PMMA decreases with ionic strength. The inhibition effect of Ca2+ on PMMA transport is stronger than that of Na+. Under the conditions of the coexistence of electrolytes with humic acid (HA), increasing the concentration of HA does not consistently enhance PMMA migration in porous media. However, citric acid (CA) exerts solely an inhibitory effect on PMMA transport. The orthogonal analysis suggests that Ca2+ concentration is the major factor affecting PMMA transport. Extended Darjaguin-Landau-Verwe-Overbeek (XDLVO) interaction energy considering the heterogeneity of HA adsorption on PMMA is calculated to quantify the interactions of PMMA-PMMA and PMMA-quartz sand under different physiochemical conditions. In unsaturated porous media, gravity leads to the creation of dominant channels, and the shear force of water flow in porous media leads to the rapid passage of PMMA through the dominant channels. However, as the water content decreases, the recovery rate of PMMA decreases from 0.99 to 0.71. Significantly, the capillary energy of a colloid retained in a thin film or at the air-water-solid (AWS) interface is several orders of magnitude larger than the XDLVO interaction energy. Findings obtained by this study may improve the current understanding of the environmental fate of nanoplastics in subsurface environments and can provide scientific methods to assess the associated risk of nanoplastics.

Рекомендації з відновлення водопропускальних труб із застосуванням металевих гофрованих конструкцій

Introduction. The reliability and durability of culverts are affected by static and dynamic loads from vehicles and temperature and climatic influences, the destructive force of water flow, abrasive destruction, corrosion of the material, shortcomings in the choice of structures and unsatisfactory design, all of which cause the premature collapse of the structure. Today, culverts made of metal corrugated structures (hereinafter referred to as metal corrugated structures) are widely used. The well-known advantages that justify the choice of such a solution are mainly a short term and a relatively low cost of construction, construction provided that the appropriate technological regime is observed does not cause any particular problems. Therefore, there is a need to develop a recommendation for the restoration of culverts using metal corrugated structures. Problems. It was established that there is a need to restore culverts without stopping the movement of vehicles. Goal. It consists in offering approaches for the restoration of culverts using metal corrugated structures.

Określenie zmian ciśnienia podczas wiercenia otworu z półzanurzalnej platformy wiertniczej

The article states that a ship in the open sea is in a complex oscillatory motion due to the aerodynamic force of water flow and hydrodynamic pressure. Among the lateral, keel, horizontal, and vertical vibrations, only the vertical vibration of the vessel primarily affects the technological process of drilling a well. The article determines the magnitude of the hydrodynamic pressure that arises in the wellbore from the oscillation of the semi-submersible drilling platform in the absence of well flushing and a telescopic string, a compensator for vertical movement. When formulating the problem accurately, one should take into account the presence of natural vibrations of both the drilling tool and the semi-submersible drilling platform from which the well is to be drilled. The semi-submersible drilling platform was awarded by Caspian Drilling Company to two subsidiaries of Keppel offshore & Marine Company with Caspian Rigbuilders and Caspian Shipyard Company. This platform, named after Heydar Aliyev, is the first and the only drilling platform in the world with a 1,400-atmosphere system technology. Its carrying capacity is 5,600 tons, and its displacement is 47,500 tons. Vertical vibrations of the semi-submersible platform, caused by hydrometeorological conditions, set in motion the drilling tool associated with the semi-submersible drilling platform, along with the flushing solution that fills the well during drilling without a riser. This leads to a change in the hydrodynamic pressure in the well. Therefore, the change in hydrodynamic pressure in the well must be checked using a special installation that simulates the vibrations of the vessel and drilling tool in a well filled with drilling fluid.

Energy Recovery from Hexavalent Chromium Reduction for In Situ Electrocatalytic Hydrogen Peroxide Production.

Recovering chemical energy embedded in pollutants is significant in achieving carbon-neutral industrial wastewater treatment. Considering that industrial wastewater is usually treated in a decentralized manner, in situ utilization of chemical energy to achieve waste-to-treasure should be given priority. Herein, the chemical energy released by the electroreduction of Cr(VI) was used to enhance on-site H2O2 generation in a stacked flow-through electrochemical system. The driving force of water flow efficiently coupled O2 evolution with 2-e O2 reduction to facilitate H2O2 generation by transporting anode-produced O2 to the cathode. Meanwhile, the chemical energy released by Cr(VI) promoted O2 evolution and impeded H2 evolution by regulating the electrode potentials, accounting for the enhanced H2O2 generation. The system could completely reduce 10-100 ppm of Cr(VI), reaching the maximum H2O2 concentration of 2.41 mM. In particular, the H2O2 concentrations in the Cr(VI)-containing electrolyte were 10.6-88.1% higher than those in the Cr(VI) free electrolyte at 1.8-2.5 V. A 24-day continuous experiment demonstrated the high efficiency and stability of the system, achieving a 100% reduction efficiency for 100 ppm of Cr(VI) and producing ∼1.5 mM H2O2 at 1.8 V. This study presents a feasible strategy for Cr(VI) detoxification and synchronous on-site H2O2 generation, providing a new perspective for innovative Cr(VI) wastewater treatment toward resource utilization.

Experimental study on local scour protection and contact pressure of the facing water surface at the pier based on the guide pillar

The safety of pier foundations is an important issue in bridge construction, where local bridge scour is a major cause of bridge damage worldwide, exacerbated by ice sheets. This paper offers a live bed scour experimental investigation that assesses the impacts of the new anti-scour device guide pillar of different sizes on geometric properties of scour, downflow velocity distribution, and turbulence intensity around the pier under different flow velocities and roughnesses, and to select the optimum installation position and size of the guide pillar. The results demonstrate that the guide pillar has a considerable effect on the scour hole and downflow around the pier, and the maximum reduction rate of scour depth is 59.3% in the optimal installation position (2d). By arranging distributed thin-film pressure sensors on the pier and measuring the pressure distribution on the facing water surface of the pier and the position of the center of gravity, this paper analyzes the distribution characteristics of the water flow force on the pier and the impact resistance of the guide pillar to the pier scour. The study found that the guide pillar reduces the water flow force by 61.3% without considering the effect of hydrostatic pressure.

The Fate of Microplastics, Derived from Disposable Masks, in Natural Aquatic Environments.

This paper mainly reviews the fate of microplastics, released from used face masks, in the water environment. Through previous experiments, the amount of fiber microplastics released from used face masks into aqueous environments was not negligible, with the maximum microplastics releasing amount reaching 10,000 piece·day-1 for each mask. Microplastic derived from these masks often occurred in the shape of polymeric fibers that resulted from the breakage of the chemical bonds in the plastic fibers by the force of water flow. The potential contact forces between microplastics (originating from face masks) with other pollutants, primarily encompass hydrophobic and electrostatic interactions. This critical review paper briefly illustrates the fate of microplastics derived from disposable face masks, further devising effective strategies to mitigate the environmental impact of plastic particle release from the used personal protective equipment.

Construction risk analysis of cantilever casting mid-span closure of bridge in reservoir area

In order to assess the impact of frequent microseismic and cyclic water flow forces on the bridge cantilever casting construction in the Three Gorges reservoir area, a limited element-quantum-orthogonal experimental design-neural network-Monte Carlo simulation method was used to analyze the risk assessment of the construction. The orthogonal experimental design method is utilized to generate probability distribution samples of water velocity, water height, and microseismic acceleration. These samples are then combined with a finite element model and trained using a BP neural network. This approach aims to establish a nonlinear mapping relationship between each control parameter and the axial deviation value in the mid-span closure, and then the Monte Carlo simulation is used to generate the random influence parameter, which can be substituted into the trained BP neural network to predict the risk of the error in the mid-axial deviation. The results suggested that the risk probability of the medial axis deviation of the closure section due to the coupling effect of water flow force and high-frequency microseismicity had reached 5.06%, and the risk of line deviation of the cantilever casting construction of the bridge in the reservoir area needed to be paid sufficient attention and prevented. The risk of line deviation of the cantilever casting construction of the reservoir bridge needs to attract enough attention and precaution.

Water flow induced piezoelectric polarization and sulfur vacancy boosting photocatalytic hydrogen peroxide evolution of cadmium sulfide nanorods

Piezo-photocatalytic H2O2 production utilizing earth-abundant solar and mechanical energies, oxygen and water is a highly appealing route to produce renewable energy carriers. However, piezoelectric polarization always suffers from high-frequency mechanical vibration, which severely restricts its actual applications. Here, we report prominent piezo-photocatalytic H2O2 evolution from pure water triggered by low-frequency water flow induced mechanical stress over 1D CdS nanorods with sulfur vacancy (CdS NRs). The polar CdS NRs possess benign piezoelectric property and favorable morphology, enabling high sensitivity and respond to weak force of water flow, which contribute to yielding large piezoelectric polarization for photogenerated charges separation. Piezoelectric polarization also shows an inhibition effect on the photocorrosion of CdS to ·SO3-. Besides, DFT calculations demonstrate that sulfur vacancy allows enhanced O2 adsorption and formation of the intermediate *OOH on the surface of CdS. Under simultaneous visible light and high-speed stirring, CdS NRs display a remarkably synergetic piezo-photocatalytic H2O2 production (1631.4 µmol g−1 h−1) without any sacrificial agents, 2.4 and 73.8 times of that under sole visible light and mechanical agitation, respectively. Importantly, it achieves an apparent quantum efficiency (AQY) of 1.32% at wavelength up to 500 nm and a solar-to-chemical (STC) conversion efficiency of 0.05% under one-sun illumination, which far exceeds other reported sulfide-based catalysts. This work integrates well with polarization engineering, defect engineering and morphology engineering to enhance catalytic behavior, providing a feasible strategy for designing efficient piezo-photocatalysts sensitive to weak mechanical forces.

Textile-based piezocatalytic platform for organics degradation under low-frequency water flow

This work presents the unique advantage of textiles in constructing piezocatalytic platforms. The mesoporous and intertwined textile could amplify the striking force of water flow, by which piezocatalysis under low-frequency water flow is achieved.

Characteristics of air flow driven by the water free surface in a free-flow spillway tunnel

Air is transported downstream by the water flow in a free-flow spillway tunnel, resulting in high negative pressure, which causes gate vibration and cavitation. In this research work, a physical model of a free-flow spillway tunnel was used to investigate the effects of water surface velocity and the area residual of tunnel cross sections on air movements. The results demonstrate that the air velocity distribution forms an S-shaped curve. As the water surface velocity increases or the area residual decreases, the air velocity increases, and the relative action height of the drag force of water flow on the air increases as well. The air velocity distribution is divided into two exponential distributions at the position where the air velocity drops by 0.2 times that of the water surface velocity. Two formulas for calculating the air velocity of the corresponding exponential distributions are developed. Subsequently, an algorithm for the air demand is presented, and the relative error compared to the reference data was less than ±20%. These results provide a reference for free-flow spillway tunnel ventilation shaft design.

АНАЛІЗ ПРОБЛЕМ ЗАБЕЗПЕЧЕННЯ НАДІЙНОСТІ ТА ДОВГОВІЧНОСТІ ГІДРОТЕХНІЧНИХ СПОРУД ТРАНСПОРТНОГО БУДІВНИЦТВА З ДОРОЖНІХ ВОДОПРОПУСКНИХ ТРУБ В УМОВАХ ЕКСПЛУАТАЦІЇ

Abstract. Introduction. Failure to ensure the reliability and durability of hydraulic structures of transport construction of road culverts in operating conditions due to static and dynamic loads from vehicles and temperature and climatic influences, the destructive force of water flow, abrasive destruction, corrosion of metal. The reason for the lack of efficiency of design solutions of road culverts is the fundamental difference in the conditions of water flow through the road culvert, at the outlet of the pipe a two-dimensional flow is formed, and and, as a consequence, the destruction of the structure of the lower reaches, landslides, the destruction of the culvert as a whole. Problems. From the literature analysis it is established that road culverts are in difficult operating conditions, which causes their premature destruction. Goal. It consists in the analysis of problems of ensuring reliability and durability of hydraulic structures of transport construction from road corrugated metal culverts. Results. The analysis of problems of ensuring reliability and durability of hydraulic structures of transport construction from road culverts in operating conditions is carried out. Proposals for calculating the initial sections of the structure to ensure its reliability are given. Conclusions. To date, the issue of ensuring the reliability and durability of hydraulic structures of transport construction of road culverts is not fully studied - alternating changes in the modes of flooding of culverts, including the operation of road culverts in part in the pressure mode; change and influence of the roughness coefficient due to the presence of corrugations, their placement; the effect of metal corrosion on the durability of the structure; abrasive wear of corrugated walls. The question of the kinetics of the initial sections of the corrugated metal culvert is insufficiently studied. Key words: highways, culverts, hydraulic stru

Research on a Critical Hydraulic Gradient of Piping in Noncohesive Soils

The critical hydraulic gradient of cohesive soil is an important condition for judging soil piping. For force analysis of movable particles in pore channels of soil, this study proposes to consider the influence of surrounding particles on the drag force of movable particles by water flow. According to the principle of relative motion, considering the interaction force between moving objects in still water, the value of the drag force of water flow that is affected by surrounding particles is calculated, to derive the method of the critical hydraulic gradient. This calculation method is suitable for the results of previous piping tests, and the method is accurate and concise.

Hydraulic model experiment of energy dissipation on the horizontal and USBR II stilling basin

Flow conditions on overflow systems can result in construction failure, mainly due to the high flow energy. Stilling basin at downstream of the spillway is useful for reducing flow energy. It can reduce the destructive force of water flow. Controlling the hydraulic jump is an important part that includes the jump’s energy, length, and height. The physical hydraulic model was carried out with several series, by making a series of bottom lowering of horizontal and USBR II stilling basin. The experimental study is expected to represent flow behavior in the overflow system regarding flow conditions and energy dissipation. Based on the analytical calculation of flow velocity, the amount of flow energy that occurs at each control point is calculated. The control points are the starting point of the spillway, the chute way toe, and flow depth after the hydraulic jump. The energy loss can be calculated for each control point, while the efficiency of energy dissipation on stilling basin is calculated at the downstream flow depth after the hydraulic jump. Velocity calculated by dividing discharge per unit width by water depth which is based on the flow depth measurement data in the hydraulic model.

Reduction of biofilm adhesion strength by adjusting the characteristics of biofilms through enzymatic quorum quenching

Biofilm adhesion to the surface of a carrier plays an essential role during biofilm formation. Quorum quenching (QQ) has been shown to have great potential for delaying biofouling. However, little is known about whether QQ reduces the adhesion strength of biofilms during the formation process to inhibit biomass accumulation. In this study, we explored the effect of enzymatic QQ on the adhesion strength during biofilm development. In addition, a quantitative method was used to measure the adhesion strength of biofilms based on the shear force of water flow. Experimental results showed that QQ enzyme could reduce the adhesion strength of biofilms by at least 37% compared with the control. Furthermore, the biofilm accumulation rates were 0.05673 and 0.08762 h−1 with and without the QQ enzyme, illustrating a negative effect of QQ enzyme on biofilm accumulation. Specifically, QQ was confirmed to reduce extracellular polymeric substances, decrease the relative hydrophobicity, change the zeta potential by degrading signal molecules, and weaken the adhesion strength of biofilms. The successful reduction of the adhesion strength of the biofilm through QQ could provide a new strategy for the management and regulation of biofilm adhesion in the bioreactor.

Sinuous bar fingers of digitate shallow‐water deltas: Insights into their formative processes and deposits from integrating morphological and sedimentological studies with mathematical modelling

AbstractThis paper helps to address the growing need to resolve the severe loss of deltaic lands by providing a new understanding for shallow‐water digitate delta growth. The integration of satellite image analysis of modern deltas, field studies of the Ganjiang Delta in the Poyang Lake and ‘Delft3D’ simulations further results in improved facies models for shallow‐water digitate deltas. These analyses show that shallow‐water digitate delta bar fingers are sinuous in contrast to the straight deep‐water digitate delta bar fingers. These differences are assigned to the effect of water depth on outflow hydraulics, where friction‐dominated shallow‐water delta effluents promote mouth bar deposition that then divert flow around the mouth bar, resulting in the formation of sinuous bar fingers. These effects are further strengthened by the meandering of the shallow‐water jet that increases lateral sediment transport, and by the higher flow resistance and lower gradient of the shallow‐water outflows. Our data and analyses further show differences in the morphology and deposits of the shallow‐water sinuous bar fingers, where some bar fingers develop sinuous and others meandering (with point bars) distributary channels. Lateral channel migration and point bar formation (meandering) occur as a secondary process that does not change the shape or width of the bar fingers themselves, and is suggested to be a function of slight initial differences in channel sinuosity. These differences in distributary channel morphology have a strong effect on bar finger facies distribution. Sediment cohesion is another important control on bar finger bending processes, because high cohesion promotes formation of enclosed bays, where their bank strength exceeds the centrifugal force of water flow. Lower sediment cohesion results in sinuous bar fingers without formation of enclosed bays. This work provides insights into natural and artificial shallow‐water digitate delta growth and provides new quantitative facies models for shallow‐water digitate deltas.

3D–3D Computations on Submerged-Driftwood Motions in Water Flows with Large Wood Density around Driftwood Capture Facility

The accumulation of driftwood during heavy rainfall may block river channels and damage structures. It is necessary to mitigate such effects by periodically capturing and removing driftwood from rivers. In this study, the behavior of driftwood in open-channel flows with a relatively large wood density was modeled numerically. The water flow and driftwood motion were solved three-dimensionally, with an Euler-type flow model coupled with a Lagrange-type driftwood motion model. A piece of driftwood was modeled as a set of connected spherical elements in a straight line for easy analysis using a discrete element method. Wood with specific gravity exceeding 1 will travel along a position near the riverbed and will be affected by bed friction. In addition, friction forces for sliding and rolling motions are considerably different. Therefore, in the numerical model, a bed friction term was introduced between the bed and driftwood considering the anisotropy of the friction force. The variation in the drag force of water flow on driftwood was also considered depending on the angle between the driftwood trunkwise direction and flow direction. The model was applied under the same conditions as those used in a laboratory experiment on driftwood behavior around an inlet-type driftwood capture facility. The computational results showed that the proposed model could qualitatively reproduce the driftwood behavior around the capture facility. The secondary flow patterns at the approaching reach and the capture ratio were found to be strongly affected by the turbulence model and the Manning roughness coefficient.

Angular momentum tearing mechanism investigation through intermolecular at the bubble interface

Two-phase flow with gas-liquid component is commonly applied in industries, specifically in the refinery process of liquid products. Oil products with bubbles contents are undesirable in a production process. This paper describes an investigation of a process mechanism regarding the bubble breakup of the two-phase injection into quiescent water. The analytical model was developed based on the force mechanism of water flow at the bubble interface. The inertia force of water flow continually pushes the bubble while the drag force resists it. The bubble gets shapes change that affects the hydrodynamic flow around the bubble. Vortices with high energy density impact and make the stress interface over its strength so that the interface gets tear. The experiment was carried out by observing in the middle part of the injected flow. It was found that the forming process of bubble breakup can be explained as the following steps: 1) sweep model is a bubble pushed by the inertial force of water flow. The viscous force of water shears the surface of the bubble. The effect of both forces, the bubble changes its shape. Then trailing vortex starts to appear in near bubble tail. The second flow of water is in around of the bubble to strengthen the vortex energy density that causes fragments to detach from the parent bubble; 2) stretching model, the apparent bubble has high momentum force infiltrated in stagnant water depth and bubble ends are stretched out by the inertial force of the bubble and viscous force of water. The bubble surface has experienced stretching and tearing become splitting away. Based on the finding, the breakup process is highly dependent on the momentum of water flow, which triggers the secondary flow as the initial process of vortex flow, and it causes the tear of the bubble surface due to angular momentum

Fatigue life of underwater wet welded low carbon steel SS400

Underwater welding is widely used for maintenance and repairs of underwater structures such as undersea pipes, offshore structures and nuclear power plants. In practice, underwater welding has the disadvantage related to high cooling rate and unstable welding arc due to the water hydrostatic pressure. This affects the microstructure and mechanical properties of underwater welded joints. Many of previous research works on underwater welding have been carried out only on a laboratory scale in shallow water depth, whereas underwater welding was used to weld in the depth of the water with a metre scale. Undersea structures experience fatigue load due to the fluctuation force of water flow. Therefore, this study aims to determine the effect of water depth on the fatigue life of underwater welded joints. Low carbon steel SS400 specimens were welded underwater with depths of 2.5 m, 5 m and 10 m. The air welded joint was also evaluated for comparison purposes. Fatigue life was evaluated according to the ASTM E466 standard by using a rotary bending machine. Furthermore, tensile test, micro hardness measurement and microstructure evaluation were also conducted for gathering supporting data. The fatigue and tensile strength of the air welded joints were higher than those of the underwater welded joints. The porosities caused by the dissolved hydrogen gas, carbon (monoxide and dioxide) gases and water vapor in weld metal of the underwater welded joints decreased the fatigue and tensile strength. An interesting phenomenon on the underwater welded joints was that the deeper the water level, the higher became the fatigue, tensile strength as well as hardness. Based on the microstructure analysis, the number of acicular ferrite structures in weld metal increased as the water level depth increased.

Reliability Analysis and Numerical Simulation of Reinforced Concrete Structure in Port Engineering

Mu, Z.; Mu, H.; Zhang, H.G., and Li, Z.-P., 2019. Reliability analysis and numerical simulation of reinforced concrete structure in port engineering. In: Gong, D.; Zhu, H., and Liu, R. (eds.), Selected Topics in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 94, pp. 347–351. Coconut Creek (Florida), ISSN 0749-0208.In addition to the normal loss and damage during the service period, the port engineering facilities are also affected by harsh environments such as water erosion, wave erosion, atmospheric corrosion and freezing and thawing. Therefore, it is very important to analyze the reliability of reinforced concrete structures. The reliability analysis of reinforced concrete members is actually based on the fact that the statistical characteristics of the existing loads and structural resistance are known, and the reliability index value of the members is determined through specific calculations to understand the failure probability. Taking the reinforced concrete frame column as an example, the finite element model is established by the simulation software to simulate and analyze the compression of the port structure under the action of ship impact force, ship system force, doorsill machine load, self-weight load and water flow force, the reliability of shear and bending capacity, the analysis results provide the basis for engineering construction and followup research.

A Sensor Redeployment Algorithm Based on Virtual Forces for Underwater Sensor Networks

Practical underwater sensor networks redeployment algorithm needs to fully consider limited node resources, node move time and other characteristics in real environment. A Redeployment based on virtual forces (RBVF) algorithm is proposed. The non-persistent carrier sense multiple access protocol is introduced to solve communication conflicts between nodes during redeployment process. Based on existing study on three-dimensional space node deployment, the threshold value is determined to divide the attractive and repulsion forces. The speed of the node is considered. Simulation results indicate that the RBVF algorithm can achieve better coverage and less total move distance when moving nodes are not considered in virtual forces calculation. Water flow force is introduced, and a Virtual forces redeployment based on energy consuming (VFRBEC) algorithm is proposed, where different energy consumptions in different directions are used to modify node displacement. Simulation results indicate that the VFRBEC algorithmcan achieve the same coverage performance with the RBVF algorithm with less energy and is better than the redeployment based on combined virtual forces algorithm in terms of both coverage and energy consumption performances.