3D Flow Model Research Articles

Modeling Groundwater Resources in Data-Scarce Regions for Sustainable Management: Methodologies and Limits

Groundwater modeling in data-scarce regions faces significant challenges due to the lack of comprehensive, high-quality data, impacting model accuracy. This systematic review of Scopus-indexed papers identifies various approaches to address these challenges, including coupled hydrological-groundwater models, machine learning techniques, distributed hydrological models, water balance models, 3D groundwater flow modeling, geostatistical techniques, remote sensing-based approaches, isotope-based methods, global model downscaling, and integrated modeling approaches. Each methodology offers unique advantages for groundwater assessment and management in data-poor environments, often combining multiple data sources and modeling techniques to overcome limitations. However, these approaches face common challenges related to data quality, scale transferability, and the representation of complex hydrogeological processes. This review emphasizes the importance of adapting methodologies to specific regional contexts and data availability. It underscores the value of combining multiple data sources and modeling techniques to provide robust estimates for sustainable groundwater management. The choice of method ultimately depends on the specific objectives, scale of the study, and available data in the region of interest. Future research should focus on improving the integration of diverse data sources, enhancing the representation of complex hydrogeological processes in simplified models, and developing robust uncertainty quantification methods tailored for data-scarce conditions.

Numerical Study of Supercritical Flow over Mesh-panel Bottom Rack Used to Estimate the Dividing Discharge Streamline in Clear Water Conditions

Bottom racks are critical for diverting flow for small hydropower projects. This study investigates the hydraulic behavior of a mesh-panel bottom rack, comprising longitudinal and transverse bars, under clear-water conditions using a numerical model developed with the Flow-3D finite volume code. The research focuses on the discharge dividing streamline (DDS) and derives an empirical regression equation for its position based on model results. The numerical model is calibrated and validated against experimental data from Bina and Saghi (2017), yielding average relative errors of 3.4% for diverted discharge (Qd) and 1.9% for remaining discharge (Qr). The pressure distribution and vertical flow velocity analyses reveal that negative pressure around the transverse bars enhances diverted discharge. The vertical velocity distribution shows that outflow begins after approximately 30% of the rack length. The deep velocity distribution extracted from the Flow-3D model matches experimental data well, achieving a coefficient of determination (R² = 0.98) and a relative error (Er = 0.32%). This study proposes a regression relation to estimate the normalized DDS position, facilitating easy determination of diverted discharge in river diversion projects by measuring the approaching flow depth. Keywords: Bottom rack, Diverted discharge ratio (DDR), Discharge dividing streamline (DDS), Flow-3D numerical model, Hydraulic behavior, Vertical flow velocity.

A comprehensive study on Maxwell hybrid nanostructure and Maxwell nanostructure on 2D flow model over a stretching sheet with non-uniform heat generation/absorption and binary chemical reaction

A comprehensive study on Maxwell hybrid nanostructure and Maxwell nanostructure on 2D flow model over a stretching sheet with non-uniform heat generation/absorption and binary chemical reaction

Effect of Mold Electromagnetic Stirring Position on Flow Field and Solidification Behavior of Four‐Hole Nozzle Arc Continuous Casting Large Round Bloom

For the special casting environment of large round bloom mold with four‐hole nozzle, the reasonable choice of mold electromagnetic stirring (M‐EMS) location is of great significance to the quality control of bloom. In this study, the four‐hole nozzle arc continuous casting of φ600 mm‐large round bloom is taken as an example, a 3D mathematical model of liquid steel flow is built, and the solidification and heat transfer under M‐EMS is established. The optimum M‐EMS position was obtained as Z = 600 mm, which is enhanced flow rates, shell uniformity, and brittle interval width, and offers valuable insights for improving casting quality.

Determining Groundwater Table in Slopes With Horizontal Drains and Design Framework for Length and Spacing

ABSTRACT Horizontal drains (HDs) are commonly implemented in slope stabilization to reduce the pore water pressure (PWP); however, they also cause complex three-dimensional (3D) variations in the groundwater table (GWT), which require intricate 3D flow models. To address this challenge, we propose a novel semi-empirical method based on a series of numerical simulations validated through numerical and field studies to determine the GWT of a slope with HDs. Subsequently, the proposed method was extended to calculate the average PWP (U) acting on a predefined slip surface via linear integration. The decrease of U (ΔU) resulting from HDs can be used to evaluate the performance of HDs. To create design charts that consider the impact of length and spacing of HDs on ΔU for a specific slope, we developed a Python-based computer program. Two case studies were conducted, which showed that ΔU increases with longer HDs and shorter spacing. The results also indicated that extending the HDs beyond a particular length does not significantly affect ΔU; it is highly sensitive to the spacing in short HDs and not sensitive in long HDs. Furthermore, we found that the total length of HDs required to achieve a target ΔU is less in wide spacings than in short spacings. In conclusion, long HDs with wide spacings are more effective and economical. Owing to the unique nature of each slope stability problem, this study offers a practical tool for analyzing the effectiveness of HDs instead of providing a general guide.

Numerical computation of Cross nanofluid model using neural network and Adaptive Neuro-Fuzzy Inference system with statistical insights for enhanced flow optimization

In this study, we present a novel integration of numerical methodologies and advanced computational intelligence to elucidate the dynamics of cross nanofluid flow over a Riga plate through a Darcy-Forchheimer porous medium. Brownian motion and thermophoretic phenomena are considered, along with the impacts of activation energy. Slip velocities, convective, and zero-flux boundary conditions are taken into account in the 3D cross nanofluid flow model in the presence of gyrotactic microorganisms. The non-linear PDE model is transformed into a highly non-linear ODE system using von Kármán similarity variables. Taking advantage of Python-derived numerical data as a foundational dataset from the system of non-linear ODEs, we employ neural network algorithms to refine and predict flow behaviors under varying conditions. The research progresses by contrasting these predictions with empirical observations, providing a rigorous validation framework. Furthermore, we incorporate the Adaptive Neuro-Fuzzy Inference System (ANFIS) alongside statistical analyses to examine the impacts of physical parameters, offering unparalleled insight into nanofluid mechanics. This multifaceted approach not only bridges theoretical and practical aspects of fluid dynamics but also proposes a robust model for predicting nanofluid behavior, poised to catalyze advancements in thermal engineering and nanotechnology applications. The precision and adaptability of our methodology underscore its potential as a cornerstone in future fluid dynamics research, inviting scrutiny and discussion from esteemed peers in the field. We have validated our model by finding various sets of error estimations. Furthermore, the velocity profile increases with the enhancement of the Hartmann number or magnetic parameter while decreasing with higher values of the Weissenberg number. The temperature profile decreases with increasing estimates of thermal stratification and the Biot number. The concentration profile amplifies with the Brownian motion parameter while decreasing against the thermophoresis parameter.

Longitudinal Investigation of Groundwater and Surface Water Interaction of Two Gravel Pit Lakes in Central Texas: Chemical and Flow Implications

Two gravel pit lakes in central Texas were examined over the course of two years with upgradient and downgradient piezometer installations. Groundwater and lake water were sampled bimonthly for nutrients, water levels, and groundwater chemistry, and in addition, rain and lake gauges and mini-piezometers were installed, depth surveys were conducted, and a simple 2D flow model was constructed. The project goal was evaluating and examining flow dynamics and chemical effects as groundwater flows to surface water and back to groundwater with the intent to understand the effects that gravel pit lake systems have on connected shallow groundwater. Both lake systems were shown to be flow-through systems that influence the water quality by decreasing the dissolved nutrients in the groundwater in their vicinity while oxygenating the water and altering the pH. However, the lakes are also prone to high levels of evaporation, meaning that minor improvements to water quality come at the cost of decreasing the quantity of water in storage within the aquifer. Similar groundwater and mine lake systems may show comparable tendencies, providing new information for water managers, regulators, and stake-holders about the potential roles that non-remediated gravel pit lakes may play in local ecosystems and aquifer dynamics.

Modeling the coupled bubble-arc-droplet evolution in underwater flux-cored arc welding

For the numerical simulation of underwater wet flux-cored arc welding, the most crucial issue is to investigate the intense interactions between the underwater bubble, arc plasma, and molten metal. However, it is a great challenge to couple them into a single numerical model. In this study, a 3D three-phase flow model is originally established, which successfully couples the dynamic bubble, arc, and droplet. A modified Lee model is employed to realize spontaneous phase transition from liquid water to bubble gas. According to the simulation results, the bubble evolution is divided into four main stages, and two bubble separation modes are recognized. It is found that, both the changing pressure field around the bubble and the varying flow direction of surrounding water contribute to the unique bubble evolution patterns. As for the droplet, its violent up-and-down oscillation at the wire tip is mainly caused by the opposite gas drag forces, which are produced by the turbulent gas flow inside the bubbles. The upward gas drag force can even make the neck of the droplet disappear. With different droplet detaching angles, two predominant droplet transfer modes are numerically produced; when the angle reaches 147°, the droplet is pushed away and becomes a spatter. Furthermore, the underwater arc is found to be subjected to compressions from both the radial direction due to bubble necking and the axial direction due to droplet growth. The arc temperature and velocity vary significantly not only during the whole droplet transfer period, but also within each bubble evolution cycle. To verify the reliability of the model, underwater welding experiments and visual sensing are conducted. The simulated results match well with the experimental ones, with an 8% error in the droplet transfer period and only a 1.4% error in the bubble evolution cycle.

Numerical simulation of scour dynamics around series of spur dikes using FLOW-3D

Spur dikes are vital structures are used to control erosion and manage flow dynamics. This study evaluates the effectiveness of multiple spur dikes in reducing scour depth around the first dike by adjusting their spacing and length. Numerical simulations were performed using the FLOW-3D-hydro model, incorporating the RNG k-ϵ turbulence model to account for low-intensity flow conditions. Results showed that parallel spur dikes significantly influenced flow direction, reducing scour depth near the first dike. Optimal configurations, with spacing set at twice the length of the dike, reduced scour depth by up to 30%. The numerical model used a nested mesh configuration for precise flow capture. A comparison of experimental and numerical results showed a strong correlation, with an R² of 0.94, RMSE of 0.03, and P-bias of 2.5%. These findings confirm the accuracy of the FLOW-3D model in simulating scour dynamics, offering key insights for hydraulic engineering applications.

Particle-Scale Research on the Unsteady Gas-Solid Flow in the Launch System with a Complex Charging Structure

Abstract This work is focused on the the intricate behavior of gunpowder particles in a dynamic gas-solid flow with sudden spatial changes, crucial for the stability in a launch system (LS) with a complex charging structure. The 3D particle-scale gas-solid flow model is developed to explore particle detail characteristics in the LS with the hollow base projectile by the CFD-DEM method. The results show that the dispersion of particles characterized by slope stacking and the horizontal stacking when particles are stationary. The axial length of horizontality is 164mm, and the thickness of it is 43mm. The majority of particles are concentrated in the sloped area, and the total length of the three slope stacking is 551mm. The height of the slope shape in the chamber changes exponentially along the axial position, while that of the slope shape in the groove increases linearly along the axial position.

Photocatalytic antibiotic degradation in coated open microchannels by applying 2D and 3D flow modeling with kinetics

The accumulation of active pharmaceutical ingredients in the aqueous environment is a serious problem that will become even more concerning in the future. In this work, the photocatalytic degradation of ciprofloxacin (CIP) in aqueous solution was assessed over P25-TiO2 coated open microchannels with gravity-driven flow under UV-A irradiation. The deposition of different amounts of TiO2 in the microchannels was carried out via a facile, self-developed procedure. The degradation kinetics of ciprofloxacin was described via the Langmuir-Hinshelwood mechanism. Since the flow characteristics in the microchannel had influence on the concentration distribution of CIP in the microchannel, the coupled momentum and mass conservation law was solved numerically in MATLAB 2023a (2D case) as well as in ANYS Fluent 2023 R1 (2D and 3D cases). Although the implemented 2D model in MATLAB 2023a allowed the preliminary estimation of the selected kinetic parameters, namely adsorption equilibrium constant and specific Langmuir-Hinshelwood rate constant, the sensitivity of the model was not satisfactory which was attributed to the empirical correlations used for the estimation of the external mass transfer coefficient. The 2D and 3D models in ANSYS Fluent 2023 R1 predicted efficiently the outlet concentration of ciprofloxacin for different inlet CIP concentrations and liquid phase flow rates. Therefore, the as developed 2D and 3D models in ANSYS Fluent 2023 R1 can be used for the design of reactors containing coated microchannels with gravity-driven flow for photocatalytic degradation of active pharmaceutical ingredients.

Evaluation of a Coupled CFD and Multi-Body Motion Model for Ice-Structure Interaction Simulation

The interaction of water flow, ice, and structures is common in fluvial ice processes, particularly around Ice Control Structures (ICSs) that are used to manage and prevent ice jam floods. To evaluate the effectiveness of ICSs, it is essential to understand the complex interaction between water flow, ice and the structure. Numerical modeling is a valuable tool that can facilitate such understanding. Until now, classical Eulerian mesh-based methods have not been evaluated for the simulation of ice interaction with ICS. In this paper we evaluate the capability, accuracy, and efficiency of a coupled Computational Fluid Dynamic (CFD) and multi-body motion numerical model, based on the mesh-based FLOW-3D V.2023 R1 software for simulation of ice-structure interactions in several benchmark cases. The model’s performance was compared with results from meshless-based models (performed by others) for the same laboratory test cases that were used as a reference for the comparison. To this end, simulation results from a range of dam break laboratory experiments were analyzed, encompassing varying numbers of floating objects with distinct characteristics, both in the presence and absence of ICS, and under different downstream water levels. The results show that the overall accuracy of the FLOW-3D model under various experimental conditions resulted in a RMSE of 0.0534 as opposed to an overall RMSE of 0.0599 for the meshless methods. Instabilities were observed in the FLOW-3D model for more complex phenomena that involve open boundaries and a larger number of blocks. Although the FLOW-3D model exhibited a similar computational time to the GPU-accelerated meshless-based models, constraints on the processors speed and the number of cores available for use by the processors could limit the computational time.

Modeling of multi-phase flow in plasma transferred arc cladding of NiCrBSi/WC metal matrix composite

In this paper, a 3D multiphase flow model has been established for the plasma transferred arc (PTA) cladding of composite powder (NiCrBSi/50 wt% WC) on a 40CrNi2MoA substrate. The multiphase flow model simulates both the discrete phase (WC particles) and continuous phase in the melt pool, including the behaviors of heat transfer and particle distribution. The buoyancy, arc pressure, surface tension, and electromagnetic force are calculated. The model is then used to predict the influences of welding currents and preheating temperatures on the depth of heat-affected zone (HAZ), the temperature field, and the dimensions of the cladding layers. To validate this model, the dimensions and the HAZ depth are analyzed and compared to experimental data. The results show that the dimensions and HAZ depth obtained by the model simulation are in good agreement with the experiment. The HAZ depth, the melt pool length, and the dimensions of cladding layer would increase with the increasing welding current or preheating temperature. Driven by the inward convection in the melt pool, WC particles tend to distribute around the center line of cladding layers. This is the first work of modeling 3D multiphase flow in PTA cladding process of particle-reinforced metal matrix composite (MMCs). The work can provide theoretical guidance for adjusting process parameters to control HAZ depth and cladding quality in actual production.

Effect of tool rotational speeds on material flow and strain rates during friction stir butt welding of AA2219-T87 plates

ABSTRACT Friction stir welding (FSW) process is widely used for joining Al-Cu alloy (AA2219-T87) plates because of its high joint efficiency and low residual stresses in contrast to fusion-based joining techniques. A two-way coupled, 3D thermal-material flow model has been developed in COMSOL software, and the effect of tool rotational speeds on thermal and material flow fields, strain rates, thermal histories, and size of weld zones are being studied. The non-uniform net heat generation during the FSW process is due to the friction between workpiece and tool materials and the deformation energy of plasticized material flow sheared by the rotating tool. An approximate range of temperatures for the weld zones has been proposed and found to be appropriate because the predicted sizes are in good agreement with the experiments. Furthermore, the authors suggested that a quality FSW joint must have the nugget zone smaller and the heat-affected zone larger than the tool shoulder diameter.

The Soret-Dufour Effects on Three-Dimensional Magnetohydrodynamics Newtonian Fluid Flow over an Inclined Plane

The three-dimensional (3D) model of the fluid flow model with length, breadth, and height or depth is the advanced and precise version from the two-dimensional (2D) model which just lies on a flat surface. The heat transfer in the boundary layer flow have numerous applications in the production of polymer, plastic films, and paper production. Therefore, this paper solves 3D magnetohydrodynamics Newtonian fluid flow model with the effect of Soret-Dufour parameters. Compared with the previous report where the 3D model is without the inclination angle (all the axes are located at their fixed position), this paper considers the boundary xy-plane being projected by a certain angle from the z-axis. The initial partial differential equations (PDEs) are subsequently reduced to ordinary differential equations (ODEs). The MATLAB bvp4c program is chosen to solve the ODEs and the results velocity profile, temperature profile, concentration profile, skin friction coefficient, local Nusselt number, and local Sherwood number. It can be inferred that the magnetic parameter is responsible to the decrement of the velocity profile and skin frictions coefficient. The enhancement of the temperature and the local Sherwood number are caused by the Dufour number. Besides, concentration and the local Nusselt number are enhancing due to the increasing Soret number.

Impact of subsurface crevassing on the depth–age relationship of high-Alpine ice cores extracted at Col du Dôme between 1994 and 2012

Abstract. Three seasonally resolved ice core records covering the 20th century were extracted in 1994, 2004, and 2012 at a nearly identical location from the Col du Dôme (4250 m above sea level, m a.s.l.; Mont Blanc, French Alps) drill site. Here, we complete and combine chemical records of major ions and radiometric measurements of 3H and 210Pb obtained from these three cores with a 3D ice flow model of the Col du Dôme glacier to investigate in detail the origin of discontinuities observed in the depth–age relation of the ice cores drilled in 2004 and 2012. Taking advantage of the granitic bedrock at Col du Dôme, which makes the ice core 210Pb records sensitive to the presence of upstream crevasses, and the fact that the depth–age disturbances are observed at depths for which absolute time markers are available, we draw an overall picture of a dynamic crevasse formation. This can explain the non-disturbed depth–age relation of the ice core drilled in 1994 and the perturbations observed in those drilled in 2004 and 2012. Since crevasses are common at high-Alpine glacier sites, our study points to the important need for rigorous investigations of the depth–age scale and glaciological conditions upstream of drill sites before interpreting high-alpine ice core records in terms of atmospheric changes.

Experimental and numerical pore-scale characterization of multi-mode heat transfer in porous ceramics exposed to a transverse heat flux

We present experimental and computational approaches to characterize the multimode heat transfer in an open-cell Si-SiC foam exposed to a transverse heat flux. The experimental setup consists of a 5×5×10 cm3 parallelepipedal 10ppi foam (83% porosity) placed within a rectangular channel, in which airflow (0-8 g.s−1) was established. The pressure drop across the foam was measured and infrared cameras were used to obtain the temperature of the heater plate and the thermal maps of the foam at the outlet and on the top. The computational approach is a 3D pore scale model of flow and multi-mode heat transfer in the channel subjected to the same conditions. A X-ray tomography technique (50 µm resolution) was used to scan the foam structure and subsequent segmentation and binarization of the data resulted to a digitalized volume of the 1000×1000×2000 voxels and about 101 million cells after meshing. The computations were performed using ANSYS Fluent. Laminar or k-ε turbulence models with enhanced wall treatment were used depending on the airflow rate. Finally, the comparison of the numerical results with experimental data shows that the relative deviation of pressure drop is less than 7.1% and that of outlet foam temperature is less than the experimental uncertainties (5-20%). Using similarity with fins, the effectiveness of foam is evaluated around 2.2.

Numerical Simulation of Water Film Flow and Breakup on Anti-Icing Surface

The flow and morphological characteristics of liquid water on the icing and anti-icing surfaces of aircraft are closely related to the icing characteristics and anti-icing surface temperature distribution. To predict the flow and breakup characteristics of a water film, a 3D model of continuous water film flow and a model of water film breakup into rivulets on an anti-icing surface were constructed based on the icing model, and the corresponding methods for solving the models were developed. Using the NACA0012 airfoil as a simulation object, the changing characteristics of height and velocity for a continuous water film with time and the morphological characteristics of rivulets formed from the breakup of a continuous water film were simulated numerically. The results indicate that, with an increase in inflow velocity, the time required for the water film to completely cover the surface and reach stability decreases. Downstream in the water droplet impact zone, the calculated values of continuous water film height align well with experiments, as well as the stream height at the continuous water film rupture location with the experimental values. With the reasonable contact angle, the calculation error of the stream width is within 10%.

Runoff Hydrograph Analysis of HEC-RAS 2D Flow Hydrodynamics Meteorological Rain-on-Grid on Observed Watershed: A Case Study of Wiroko Sub-Watershed

In contemporary hydrological analysis, numerical models have emerged as an alternative solution for water resources planning and management, particularly in forecasting extreme events and mitigating disaster risks. HEC-RAS 2D flow hydrodynamics enables the modeling of rainfall with input from meteorological boundary condition data. Precipitation within the studied watershed can be modeled as point rainfall or area-averaged rainfall in the rain-on-grid feature of HEC-RAS 2D flow hydrodynamics. In this study, the HEC-RAS 2D flow model utilizes the diffusion wave equations (DWE) for simulating unsteady flow routing. When modeling a complex watershed, the 2D hydrodynamics model has become a viable alternative, especially concerning the watershed's physical characteristics. This study aims to assess the reliability of HEC-RAS 2D flow hydrodynamics and compare its results with the hydrograph data from the observed watershed in the Wiroko Sub-Watershed of the upper Wonogiri Dam. In this research, extreme rainfall events of 100 mm in the first hour are simulated and compared with the hydrograph data from the observed watershed. Based on the numerical model results in the Wiroko Sub-Watershed, it was determined that conforming to the land use with a Manning roughness value of 0.12 (designated as developed area-medium intensity) resulted in a peak discharge (Qp) difference of 0.8%. Meanwhile, the time to peak (Tp) value exhibited a discrepancy of 1.93 hours longer between the numerical model and the observed hydrograph.

Mathematical modelling for groundwater management for multilayers aquifers (Erbil basin)

This study addresses the pressing issues of groundwater depletion and drought problems in the Erbil basin, a vital resource region in the Middle East. Focused on an area of strategic importance due to its large size and critical water resources, the study employs the Groundwater Modeling System (GMS) software to create a detailed 3D hydrogeological model based on extensive borehole data. With over 240 boreholes analyzed, the study strategically selects 70 accurate wells drilled by the Groundwater Directorate. The construction of the 3D stratigraphic models for the Erbil basin relies on three main historical data including boreholes, geological formations and a comprehensive approach, incorporating deep well logging data and the definition of distinct geological layers. By discerning the presence of previous and impervious layers, the model effectively categorizes the aquifer types within the Erbil basin. The aquifer system is delineated based on stratigraphic units, designating materials with high conductivity (silt, sand, and gravel) as aquifers and clay (or claystone) as aquitards. A 3D steady-state groundwater flow model is successfully executed, employing PEST pilot point for automated parameter estimation. The model, validated with a coefficient of determination (R2) of 0.9998, reveals hydraulic conductivity values ranging from 0.000980705 to 100 m/day and a recharge value of 0.000976443 m/day. The study classifies Erbil's aquifer types as unconfined, confined, and semi-confined, providing a valuable foundation for groundwater management. The primary objective of this study is to construct a calibrated numerical groundwater model for the multi-aquifer system in the Erbil basin. The model aims to serve as a robust tool for analyzing the sustainability of diverse groundwater infrastructure development strategies within the region. The Erbil basin poses unique challenges for groundwater modeling, marked by a scarcity of critical data such as monitoring well information, pumping rates, recharge rates, and flow budgets. In response to these limitations, the study adopts an innovative approach by integrating in situ data with earth observation data. The integration of these datasets seeks to overcome data constraints and enhance the accuracy of the groundwater model. By achieving calibration and validation of the numerical model, this research strives to provide a valuable resource for decision-makers, planners, and stakeholders involved in groundwater management in the Erbil basin. Ultimately, the study aims to contribute to the development of sustainable and effective strategies for the utilization and preservation of groundwater resources in this vital region and also to enhance practical management strategies for the Erbil groundwater basin, ensuring sustainable utilization of the crucial sub-surface water resources, an objective successfully achieved through this research.