Open Channel Research Articles

Reinvestigating the Kinetic Model for the Suspended Sediment Concentration in an Open Channel Flow

The prediction of sediment transport, related to different environmental and engineering problems, requires accurate mathematical models. Most available mathematical models for the concentrations of suspended sediments are based on the classical advection diffusion equation, which remains not efficient enough to describe the complete behavior related to sediment–water two-phase flows and the feedback between the turbulent unsteady flow and suspended sediments. The aim of this paper is to reinvestigate the kinetic model for turbulent two-phase flows, which accounts for both sediment–turbulence interactions and sediment–sediment collisions. The present study provides a detailed and rigorous derivation of the kinetic model equations, clarifications about the mathematical approach and more details about the main assumptions. An explicit link between the kinetic model and the classical advection diffusion equation is provided. Concentration profiles for suspended sediments in open channel flows show that the kinetic model is able to describe the near-bed behavior for coarse sediments.

A numerical study of diversion flow to determine the optimum flow system in open channels

Abstract The term ‘branching flow’ describes water extraction from streams or main channels via secondary lateral channels. Through using 3D model simulation, the aim is to identify the ideal angle of diversion based on the maximum flow rate to the branching channel and the minimum zone of separation size attained at the entrance channel for the eight grades (90°, 75°, 60°, 45°, 30°, 25°, 20°, and 15°). An experimental study has previously been confirmed, and this paper provides a comprehensive implementation of the numerical solution (finite volume) using Flow 3D version 11.0.4 software. The validation study was conducted at the Babylon University/College of Engineering/Laboratory of the fluid. The study presented results for many different flow discharge ratios depending on two inflow discharges (12.5 and 18.5 L/s). The comparison between the numerical model and the experimental results revealed statistically a good agreement. The final results demonstrated that a diversion angle of 25° had the most significant optimum angle with the maximum discharge ratio, a minimum separation zone size, and minimum energy losses. Furthermore, the flow rate peaks in the bifurcating channel (5.76 and 8.11 L/s), which accounts for roughly 46.06 and 43.83%, respectively, from the main channel flow.

Smart Assist System Module for Paralysed Patient Using IoT Application

Those who are hearing impaired or hard of hearing face the most difficult challenges as a result of their handicap. To establish a bond or commit to something, people should be able to express their ideas and feelings via open channels of communication. To solve such issues, simple, transportable, and accurate assistive technology will probably be developed. The glove with sensors and an Arduino microcontroller is the major focus. This system was developed specifically to translate sign languages while analyzing gesture locations using smart technologies in custom gloves. The micro-controller identifies certain hand motions using sensors attached to gloves and converts sensor output data into text. Their capacity to converse may be aided by their ability to read the text on the mobile IOT application. Also, it aids in automating the houses of people with paralysis. It has the capacity to assess biological indicators like pulse and temperature as a patient monitoring device. The system will be put into place with the intention of enhancing the quality of life for people with disabilities and providing additional assistance in bridging the communication gap. It has a low price tag and a small design.

Unveiling a novel silicene-like material: A DFT study on pentahexoctite-silicon and its optoelectronic characteristics

Silicon-based two-dimensional (2D) materials, including well-known silicene, have garnered considerable attention due to their potential in advanced optoelectronic applications. Here, we introduce a novel 2D silicon variant, pentahexoctite silicon (PH-Si), inspired by the unique structural attributes of pentahexoctite carbon. By using state-of-the-art density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations, we investigated the fundamental optoelectronic and structural traits of PH-Si. Our findings reveal that PH-Si boasts promising electronic properties characterized by anisotropic conductance and metallic behavior along specific directions. We also examine its structural and dynamic stability through phonon calculations and AIMD simulations. PH-Si structural stability was also confirmed by its low formation energy of −3.62 eV and dynamical stability at 1000 K. The material exhibits optical absorption in visible (Vis) and ultraviolet (UV) spectral regions, positioning it as a potential Vis-UV detector and absorber. Additionally, we assess its crucial mechanical attributes, encompassing elastic stiffness constants, Young’s modulus (ranging from 5 to 40 GPa), and a Poisson ratio of 0.8, collectively offering valuable insights into its mechanical performance. The comprehensive exploration of PH-Si’s properties is a step towards diversifying silicon-based 2D materials, opening channels for innovative applications in the rapidly evolving field of flat electronics.

Vertical structure of flows on a shallow reef flat: A coral reef surf zone

We present a 1D model of the vertical structure of wave-driven flows on a shallow coral reef and compare that model to observations made on the reef flat on Ofu, American Samoa. This model is based on longstanding approaches to modeling flow structure in beach surf zones including the averaged effects of breaking and broken surface waves. Waves enter the model through an imbalance between the radiation stress and barotropic pressure gradients that exists below the troughs of the waves, which is offset by turbulent shear stress gradients. Assuming that the depth varying eddy viscosity takes the form found in open channel flows, i.e., a parabola, the horizontal momentum equation can be integrated twice with respect to height to derive the distribution with height of the velocity. The resulting theory is compared to observations made on a reef flat located on Ofu, American Samoa. Using a velocity scale in the eddy viscosity model that is proportional to the rms wave velocity, modeled profiles match observations reasonably well (average skill= 0.66), although there is some ambiguity introduced because matching observations and theory requires the addition of a correction that is found to depend on the square of the rms wave height.

From Sparse to Dense Representations in Open Channel Flow Images with Convolutional Neural Networks

Convolutional neural networks (CNN) have been widely adopted in fluid dynamics investigations over the past few years due to their ability to extract and process fluid flow field characteristics. Both in sparse-grid simulations and sensor-based experimental data, the establishment of a dense flow field that embeds all spatial and temporal flow information is an open question, especially in the case of turbulent flows. In this paper, a deep learning (DL) method based on computational CNN layers is presented, focusing on reconstructing turbulent open channel flow fields of various resolutions. Starting from couples of images with low/high resolution, we train our DL model to efficiently reconstruct the velocity field of consecutive low-resolution data, which comes from a sparse-grid Direct Numerical Simulation (DNS), and focus on obtaining the accuracy of a respective dense-grid DNS. The reconstruction is assessed on the peak signal-to-noise ratio (PSNR), which is found to be high even in cases where the ground truth input is scaled down to 25 times.

Spontaneous motion of solid object on open channel

Spontaneous motion of a solid object floating on an unsymmetrical geometric open channel is investigated. The open channel was created by selectively fabricating hydrophilic patterns on a superhydrophobic substrate, confining water within the hydrophilic region, thus forming a distinct open channel. As a rectangular foam block was placed on a triangular open channel, the variation of the spanwise width of the wetted area leads to a gradient of surface tension force along the centerline that is able to drive the foam block directionally. What is more, two open channels could be parallelly arranged together to drive even larger object. A theoretical model was developed to explain the mechanism, which agrees well with the experimental results. The findings of this work extend the application of capillary force, which could be used in areas such as self-driven microfluidics, surface lubrication, and open microchannels.

Effect of equilibrium and non-equilibrium sediment transport flows on the shear velocity in an open channel.

Equilibrium and non-equilibrium sediment transport flow in natural rivers and artificial channels can result in degradation or aggradation of the river bed, which will affect many hydraulic parameters, one of which is shear velocity. This study evaluates the influence of sediment transport on shear velocity in open channels. In this study, laboratory experiments were carried out using a sediment-recirculating flume, and measurements of the velocity and Reynolds shear stress distributions were measured using a Sontek-acoustic Doppler velocimeter (ADV). This experimental study measured 120 velocity distributions, and Reynolds stress profiles, consisting of 12 different sets of measurements involving flow with sediment transport and movable sand bed. The results showed an average shear velocity, u*, difference between sediment feeding and without sediment feeding by 9.41%. For the integration constant Br value, the average difference between sediment feeding and without sediment feeding was 5.58%.

Construction of imide‐linked covalent organic frameworks with palladium nanoparticles for oxygen reduction reaction

AbstractCovalent organic frameworks (COFs) have been widely employed as electrocatalysts for oxygen reduction reaction (ORR) due to their diverse and tunable skeletons and pores. However, their electrocatalytic activity was limited due to the lack of highly active catalytic sites. In this work, we have first immobilized palladium nanoparticles (NPs) into the crystal, porous, and stable imide‐linked COF for ORR. The newly designed COF had pyridine linkers with imide‐linkages in the frameworks serving as the binding sites to anchor Pd sites, and the high surface area and open pore channels provide fast mass transport pathway to the active Pd sites, which contributed highly active performance in ORR. And the designed catalyst delivered onset potential and the half‐wave potential of COF‐Pd of 0.97 and 0.83 V, with a limited current density of 6.1 mA cm−2, respectively. This work provides us insights into developing high crystalline COFs with metal NPs in electrocatalytic systems.

The ethics perspective of physics department chairs

Although a new American Physical Society ethics survey shares some conclusions with a previous one, disparities between the two highlight the need for improved procedures and open communication channels in physics departments.

Analyzing land use land cover (LULC) changes induced by the run-of river project and respondent survey: a case of Ghazi Barotha Hydropower Project on Indus River, Pakistan

Land use land cover (LULC) change determination caused by development projects is always mandatory as land is the major source of local livelihoods and regional economy. Worldwide, very limited studies have been conducted to determine LULC changes caused by run-of-the-river projects, which are generally considered safe due to their design. Present study used Google Earth Engine (GEE) to examine the LULC changes caused by Ghazi Barotha Hydropower Project (GBHP), which is a run-of-the-river project, built in 2002 on Indus River in Pakistan. The project diverts river water from Ghazi barrage, for a 6,600 GWh annual power production, through an open concrete power channel of 100 m width and 9 m depth. Field surveys were carried out to assess respondents’ opinions about LULC changes and their major causes. LULC determination was carried out from 1990–2020 through processing Landsat images in GEE, and Random Forest (RF) machine learning technique was used for supervised classification of the study area. 384 respondents were consulted during the field survey and their responses were collected using semi-structured self-administered proformas. Results showed that after functioning, GBHP caused major LULC changes in project downstream areas from 2002–2010, as there was a significant decrease in area under agriculture by 29.10% and 47%, during summer and winter seasons respectively. The trend was concurrent with a decrease in area under water and was also followed by a marked increase in area under vegetation and baresoil. However, from 2010–2020, agriculture area again increased by 75.61% and 84.53% in summer and winter seasons respectively, as compared to 2002–2010. Respondents during the field survey revealed that agriculture reduction from 2002–2010 was due to water scarcity caused by GBHP; also leading to vegetation and baresoil increase. Recovery of agriculture from 2010–2020 was attributed to groundwater development intervention, better seeds, and farmers’ capacity building.

DAC‐MD: A privacy preserving drone‐access control scheme for last mile delivery

AbstractThe service delivery has lately witnessed strides in the form of paradigm shifts from conventional logistics to drone‐oriented supply chain to conserve ecosystem. The use of drones or unmanned aerial vehicles (UAVs) for package deliveries offer enhanced accessibility, flexibility, efficiency, speed, safety, and even few environmental gains. However, the drones can come across various security hazards while communicating with ground installations on open channels including physical capture attack, privacy infringement, and so on. Thus, earnest endeavors are needed to fix those security challenges in applications related to drone communications. To address these problems, an efficient authenticated key agreement technique, drone access control scheme for last mile delivery (DAC‐MD) is suggested for user‐drone interactions in IoD environment that help the participating entities in developing a mutually agreed session key for securing subsequent communication interactions. The proposed scheme is proved using automated ProVerif tool as well as analyzed by using formal analysis based on RoR random oracle model. The comparative analysis against recently presented known studies reveals that our scheme not only carries comparable properties in terms of security and privacy, but also low computational and communication costs.

Mixing of the Connecticut River Plume During Ambient Flood Tides: Spatial Heterogeneity and Contributions of Bottom‐Generated and Interfacial Mixing

AbstractThe Connecticut River plume is influenced by energetic ambient tides in the Long Island Sound receiving waters. The objectives of this modeling study are (a) characterizing the spatial heterogeneity of turbulent buoyancy fluxes, (b) partitioning turbulent buoyancy fluxes into bottom‐generated and interfacial shear contributions, and (c) quantifying contributions to plume‐integrated mixing within the tidal plume. The plume formed during ambient flood tides under low river discharge, spring tides, and no winds is analyzed. Turbulent buoyancy fluxes (B) and depth‐integrated B through the plume (Bd) are characterized by pronounced spatial heterogeneity. Strong mixing (Bd ∼ 10−5‐10−4 m3/s3) occurs near the mouth, in the nearfield plume turning region, over shoals, and nearshore shallow areas. Low to moderate mixing (Bd ∼ 10−8‐10−6 m3/s3) occupies half the plume. Buoyancy fluxes are first partitioned based on the depth of the shear stress minimum between plume‐generated and bottom‐generated shear maxima. Four other tested partitioning methods are based on open channel flow and stratified shear flow parameterizations. Interfacial and bottom‐generated shear contribute to different areas of intense and moderate mixing. All methods indicate a significant plume mixing role for bottom‐generated mixing, but interfacial mixing is a bigger contributor. Plume‐integrated total and interfacial mixing peak at max ambient flood and the timing of peak bottom‐generated mixing varies among partitioning methods. Two‐thirds of the mixing occurs in concentrated intense mixing areas. A parameter space with the ambient tidal Froude number and plume thickness to depth ratio as axes indicates many tidally modulated plumes are moderately to dominantly influenced by bottom‐generated tidal mixing.

Wenlanzhangite–(Y) from the Yushui deposit, South China: a potential proxy for tracing the redox state of ore formation

Abstract Mineral phases in which vanadium (V) and heavy–rare–earth elements (HREEs) coexist are rarely documented. Here, we report a new V–HREE–bearing silicate mineral species, wenlanzhangite–(Y), which is a vanadiferous derivate of jingwenite–(Y) [Y2Al2V4+2(SiO4)2O4(OH)4] coexisting with jingwenite–(Y) in bedded/massive ores at Yushui, South China. Wenlanzhangite–(Y) forms as a dark brown, 70–100 μm–thick rim on a core domain of jingwenite–(Y), which occurs as 100–200 μm columnar crystals. The colour, streak, lustre, and hardness (Mohs) are dark brown, yellow grey, vitreous, and ~4, respectively. Compared to jingwenite–(Y), wenlanzhangite–(Y) has higher vanadium and lower aluminium contents. Calculated on the basis of 8 cations, the empirical formula is (Y1.26Dy0.17Er0.11Gd0.09Yb0.09Nd0.09Sm0.06Sc0.04Ho0.03Ce0.02Tb0.02Tm0.02Pr0.01)Σ2.00(V3+1.46Al0.54)Σ2.00V4+2(SiO4)2O4(OH)4, which can be simplified to the ideal formula Y2V3+2V4+2(SiO4)2O4(OH)4. Wenlanzhangite–(Y) is triclinic, with space group P–1(#2), Z = 2, and unit–cell parameters a = 5.9632(7) Å, b = 9.599(1) Å, c = 9.9170(9) Å, α = 90.033(8)°, β = 98.595(2)°, γ = 90.003(9)°, and V = 561.28(10) Å3. Wenlanzhangite–(Y) is approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification (IMA2022–142). The structure of wenlanzhangite–(Y) is composed of a–axis–oriented chains of [VO6] octahedra consisting of edge–sharing octahedra linked by insular [SiO4] tetrahedra, leaving open channels occupied by rare earth elements. Observed compositional variation and crystal structure demonstrate that V3+ can substitute for Al3+ in jingwenite–(Y), forming wenlanzhangite–(Y). The occurrence of wenlanzhangite–(Y) indicates a relatively more reducing hydrothermal environment causing reduction of V5+ in oxidized fluids to V3+ and thus represents a useful proxy for tracing the redox state of ore formation.

Physics-informed neural network for solution of forward and inverse kinematic wave problems

The one-dimensional kinematic wave (KW) model (KWM) is widely used in surface water and water quality hydrology as well as for modeling the movement of traffic on long highways. The KW model involves a first-order nonlinear partial differential equation which is solved numerically for realistic geometric representation, input, and initial and boundary conditions. This paper developed a method to solve the partial differential equation using a neural network structure, called the physics-informed neural network (PINN). The PINN was applied to solve the one-dimensional nonlinear KWM for forward and inverse problems. To enhance the accuracy and convergence and to suppress the spurious oscillation at the steep front, a technique with redistributed collocation points as an improved algorithm of PINN was employed. To deal with the fractional order of the nonlinear advection term, a stop-gradient technique was proposed. For validation, the KWM for steady and unsteady overland flow, and open channel flow without lateral inflow was analyzed for the forward problem. For the inverse problem, the unknown Manning coefficient was correctly computed, demonstrating the capability of the proposed algorithm for the identification of KWM parameters.

Momentum transfer across an open-channel, turbulent flow

The distribution of stress generated by a turbulent flow matters for many natural phenomena, of which rivers are a prime example. Here, we use dimensional analysis to derive a linear, second-order ordinary differential equation for the distribution of stress across a straight, open channel, with an arbitrary cross-sectional shape. We show that this equation is a generic first-order correction to the shallow-water theory in a channel of large aspect ratio. It has two adjustable parameters – the dimensionless diffusion parameter, $\chi$ , and a local-shape parameter, $\alpha$ . By assuming that the momentum is carried across the stream primarily by eddies and recirculation cells with a size comparable to the flow depth, we estimate $\chi$ to be of the order of the inverse square root of the friction coefficient, $\chi \sim C_f^{-1/2}$ , and predict that $\alpha$ vanishes when the flow is highly turbulent. We examine the properties of this equation in detail and confirm its applicability by comparing it with flume experiments and field measurements from the literature. This theory can be a basis for finding the equilibrium shape of turbulent rivers that carry sediment.

No Stone Unturned

A prefatory note from the editorial collective. When the Society for Cultural Anthropology selected our distributed, international editorial collective to lead Cultural Anthropology, they did so in part to support our commitment to opening channels of this crucial platform of our discipline beyond the scope of privileged, endowed higher educational institutions in the United States. As one step of this process, in this issue we provide space to the Choctaw Nation of Oklahoma to describe their work since the passage of the Native American Graves Protection and Repatriation Act (NAGPRA) in 1990. As Deanna L. Byrd, the NAGPRA Liaison-Coordinator and Research and Outreach Program Manager of the Choctaw Nation of Oklahoma, and Ian Thompson, the Tribal Historic Preservation Officer of the Choctaw Nation of Oklahoma, writes, since that time, “Native American communities gained a measure of say in how ancestral burials are treated on federal lands. The law also established a mechanism to help Native American, Alaskan, and Native Hawaiian communities have open dialogue with institutions across the country about the return of their ancestors, funerary objects, sacred objects, and objects of cultural patrimony.” Please read the rest of their guest commentary to learn more.

Swash-flow induced forces on human body standing on a smooth and impermeable slope: A numerical study with experimental validations

ABSTRACT Swash flow poses a significant hazard to pedestrians standing on the slope of the seawall. Unlike the forces of overtopping flow or open channel flow on the human body, which have been studied before, swash flow has two distinct cycles within one wave period: onshore flow and offshore flow. Both cycles can risk human safety by exerting hydrodynamic forces on the body. This paper presents a numerical study to examine the hydrodynamic forces exerted on the human body when subjected to swash flow on a smooth and impermeable slope. A Reynolds-averaged Navier-Stokes (RANS) model is set up in OpenFOAM, where the numerical results are compared with experimental data obtained from wave tank tests. Reasonable agreement has been achieved, which validates the numerical model. We examine the kinematics of swash flow generated by plunging and surging breakers. In the case of a plunging breaker, we observe that the instantaneous runup height exhibited asymmetry, whereas it is nearly symmetric for a surging breaker. The velocity profile is then used to compute the momentum flux of the swash flow, which is shown to be associated with the inline forces exerted on the human body. We have defined an instability index to assess the risk of pedestrian mobilisation by swash flow, demonstrating its dependence on the Iribarren number and the body's position. The analysis reveals that the associated risk is substantially reduced as the Iribarren number increases and when the body moves towards the shoreline.

Factors promoting the release of picrotoxin from the trap in the GABA(A) receptor pore

Picrotoxin (PTX), a convulsant of plant origin, has been used in many studies as research tool. PTX is the open channel blocker of the GABAA receptor (GABAAR). Being in the pore, PTX initiates transfer of the channel to the closed state and thus it falls into the “trap”. The consequence of this PTX trapping is so-called aftereffect, i.e. continuation of the blockade of the GABA-induced chloride current (IGABA) after removal of PTX from the external solution. The present work shows that the positive allosteric modulators (PAMs) of the GABAA receptor, allopregnanolone (Allo) and zolpidem (Zolp) as well as a high concentration of GABA shortened the PTX aftereffect. Experiments were carried out on isolated Purkinje neurons of the rat cerebellum using the whole-cell patch-clamp method. IGABA was induced by applications of 5 μM GABA (EC30) for 1 s with 30 s intervals. 50 μM PTX completely blocked IGABA, and recovery upon PTX washout occurred with a time constant (τrec) of 20.2 min. 1 μM Allo reduced the blocking effect of PTX by 30% and accelerated the recovery of IGABA by almost 10 times (τrec = 2.4 min). 0.5 μM Zolp did not change the IGABA block in the presence of PTX but accelerated the recovery of IGABA by more than 3 times (τrec = 5.6 min). Increasing the GABA concentration to 20 μM did not change the blocking effect of PTX, but accelerated recovery by 6 times (τrec = 3.3 min). The mechanism of the shortening of the PTX aftereffect is presumably the expansion of the GABAAR pore in the presence of PAMs and a high concentration of the agonist and, as a consequence, the escape of PTX from the “trap”. The work describes new pharmacological properties of Allo and Zolp.

Structural identification of a selectivity filter in CFTR

The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel that regulates transepithelial salt and fluid homeostasis. CFTR dysfunction leads to reduced chloride secretion into the mucosal lining of epithelial tissues, thereby causing the inherited disease cystic fibrosis. Although several structures of CFTR are available, our understanding of the ion-conduction pathway is incomplete. In particular, the route that connects the cytosolic vestibule with the extracellular space has not been clearly defined, and the structure of the open pore remains elusive. Furthermore, although many residues have been implicated in altering the selectivity of CFTR, the structure of the "selectivity filter" has yet to be determined. In this study, we identify a chloride-binding site at the extracellular ends of transmembrane helices 1, 6, and 8, where a dehydrated chloride is coordinated by residues G103, R334, F337, T338, and Y914. Alterations to this site, consistent with its function as a selectivity filter, affect ion selectivity, conductance, and open channel block. This selectivity filter is accessible from the cytosol through a large inner vestibule and opens to the extracellular solvent through a narrow portal. The identification of a chloride-binding site at the intra- and extracellular bridging point leads us to propose a complete conductance path that permits dehydrated chloride ions to traverse the lipid bilayer.