Simulation Of Surface Flows Research Articles

Evaluating surface and subsurface fluxes in hydrological models to advance basin-scale operational water supply forecasting

ABSTRACT Comprehensive assessments of hydrological components are crucial for enhancing operational water supply simulations. However, hydrological models are often evaluated based on their surface flow simulations, while the validation of subsurface and groundwater components tends to be overlooked or not well documented. In this study, we evaluated the outputs of two hydrological models, the Large Basin Runoff Model (LBRM) and the Weather Research and Forecasting – Hydrological modeling extension package (WRF-Hydro), for potential implementation in operational water balance forecasting in the Great Lakes region. We examined the simulated hydrological variables including surface (e.g. snow water equivalent, evapotranspiration, and streamflow), subsurface (e.g. soil moisture at different layers), and groundwater components with observed or reference data from ground-based stations and remotely sensed images. The findings of this study provide valuable insights into the capabilities and limitations of each model. These findings contribute to more informed water management strategies for the Great Lakes region.

Simulation of granular surface flows using incompressible non-Newtonian SPH (INNSPH) method

This study presents a comprehensive continuum approach to modeling granular surface flows using the Incompressible Non-Newtonian Smoothed Particle Hydrodynamics (INNSPH) method. The model integrates an incompressible SPH method, where pressure is computed by solving a pressure-Poisson equation with a non-Newtonian rheology. Projection-based SPH has a strong and rigorous theoretical basis can lead to stable and accurate simulations. This paper aims to develop a projection-based SPH method for modeling complex granular flows. INNSPH method combines incompressible SPH and μ(I) rheology models to simulate non-Newtonian viscoplastic fluid behavior in granular flows. Surface deposition, and velocity and pressure fields are estimated using a rheology model. Validation is performed by comparing simulation results, including surface profiles and run-out distances with experimental data, showing good agreement. INNSPH method is then employed to model a 2D column collapse and a dam-break scenario on horizontal and inclined planes for sands and glass beads. The method captures three distinct final deposition morphologies; truncated cone, conic, and Mexican hat shapes in collapsing columns. INNSPH computational efficiency enables simulations of large-scale granular flows, and its open-source nature facilitates collaboration and further modifications by researchers. The method provides a good understanding of granular flow dynamics in various industrial applications including powder technology.

Simulation and investigation into the pluvial effect on peri-urban unsewered drainage basin of Kolkata due to rapid urbanization

A pluvial effect is a geologic event caused by the action of water during excessive precipitation in a particular region, resulting in water logging, which affects the drainage system of that area, or it may be caused by the spill of a large amount of water beyond the normal limit from the water bodies. The pluvial effect is also referred to as a flood having highly devastating consequences when it affects a region's urban or peri-urban areas. It affects the day-to-day activities of people staying in those areas and causes various social and economic losses. This effect would even grow further if proper planning and management of land were not done in a given time. Therefore, through this paper, the authors try to address the issue of urban flooding along with its consequences and impacts. For this study, the peri-urban region of the Tollygunge-Panchannagram Basin in Kolkata, India, is considered. The zero inertia model, Triangular Irregular Network Flood (TINFLOOD), is employed for surface flow simulation, whereas the storm water management model (SWMM) is used to determine the lateral flow. The output of this study provides various hyetographic presentations, considering infiltration during advanced, intermediate, and delayed rainfall conditions. Here, the time of concentration is also examined for different rainfall intensities to observe the time for peak flow. The simulated data obtained from this model has been validated with the real-time data of a pumping station situated at Chowbhaga. Nevertheless, this study helps assess flood risk management upstream of a region's basin and peri-urban areas.

An Improved Neural Particle Method for Complex Free Surface Flow Simulation Using Physics-Informed Neural Networks

The research on free surface flow is of great interest in fluid mechanics, with the primary task being the tracking and description of the motion of free surfaces. The development of numerical simulation techniques has led to the application of new methods in the study of free surface flow problems. One such method is the Neural Particle Method (NPM), a meshless approach for solving incompressible free surface flow. This method is built on a Physics-Informed Neural Network (PINN), which allows for training and solving based solely on initial and boundary conditions. Although the NPM is effective in dealing with free surface flow problems, it faces challenges in simulating more complex scenarios due to the lack of additional surface recognition algorithms. In this paper, we propose an improved Neural Particle Method (INPM) to better simulate complex free surface flow. Our approach involves incorporating alpha-shape technology to track and recognize the fluid boundary, with boundary conditions updated constantly during operation. We demonstrate the effectiveness of our proposed method through three numerical examples with different boundary conditions. The result shows that: (1) the addition of a surface recognition module allows for the accurate tracking and recognition of the fluid boundary, enabling more precise imposition of boundary conditions in complex situations; (2) INPM can accurately identify the surface and calculate even when particles are unevenly distributed. Compared with traditional meshless methods, INPM offers a better solution for dealing with complex free surface flow problems that involve random particle distribution. Our proposed method can improve the accuracy and stability of numerical simulations for free surface flow problems.

Quantitative assessment of computational efficiency of numerical models for surface flow simulation

Abstract To improve computational efficiency without accuracy losses for surface flow simulation, a dynamic bidirectional coupling model based on multigrid was applied. The flood-prone areas, where the inundation conditions were needed to detail, were discretized using finer grids, while the rest of the domains were assigned coarser grids to reduce computation time. Different time steps were adopted in coarse and fine grids. This paper presented an approach to quantitatively assess the computational efficiency under different domain discretization and grid generation conditions. Three test cases were considered to demonstrate the performance of the applied model. The results showed that the model had high computational efficiency while maintaining satisfactory simulation accuracy. The computational efficiency of the model was not only related to the size ratio of coarse to fine grids, but the area ratio of coarse grids to the entire computational domain. If the area ratio of coarse grids to the computational domain was constant, the computational efficiency improved exponentially with the increasing size ratio. If the size ratio of coarse to fine grids was constant, the computational efficiency improved linearly with the increasing area ratio. The proposed method offers a promising option for quantitatively assessing the computational efficiency of models.

Degradation of sulfonamide antibiotics in the rhizosphere of two dominant plants in Huixian karst wetland, Guangxi, China

Abstract In this work, Phragmites australis and Vallisneria natans were selected as the research objects and were cultured for 10 d under 0.10 μg L−1 sulfadiazine (SD) stress in a simulated surface flow wetland reactor. SD degradation was conducted at pH = 7 and 25 °C for 96 h. Each plant group conformed to the first-order kinetic model of degradation, and the degradation rate increased with time, reaching the maximum at 96 h. At 96 h, the degradation rate of P. australis communities was higher than that of V. natans. SD metabolites showed that the degradation pathways in the plant rhizosphere were mainly hydroxylation, aminolation, and S–N bond cleavage. In the analysis of rhizosphere bacterial community structure, the bacterial phyla that could degrade antibiotics accounted for a large proportion. Compared with before degradation, the dominant phylum and genus did not change after degradation (96 h), but their abundance changed to varying degrees, and new genera appeared in the P. australis group. This research provides a reference for the degradation of antibiotics in karst areas and new information on the mechanism of SA degradation in the plant rhizosphere.

Dissolved organic matter derived from aquatic plants in constructed wetlands: Characteristics and disinfection byproducts formation

Constructed wetlands are used to improve water quality in the drinking water sources, but aquatic plants planted in constructed wetlands may be a source of disinfection by-product (DBP) precursors. This study explored the characteristics of aquatic plant-derived dissolved organic matter (DOM) and DBP formation in micro-polluted raw water treated by constructed wetlands. A simulated surface flow wetland (SSFW) planted with the typical aquatic plants Lythrum salicaria and Acorus calamus was studied. Raw water, control samples, effluent, and Suwannee River natural organic matter (SRNOM) were analyzed. via ultraviolet-visible (UV-Vis) spectroscopy, three-dimensional excitation emission matrix (3D-EEM) fluorescence combined with a parallel factor (PARAFAC) analysis, liquid chromatography-organic carbon detection (LC-OCD), principal component analysis (PCA), and other detection and analysis methods. A DBP formation potential (DBPFP) index was also constructed. Treatment by the SSFW increased the effluent dissolved organic carbon (DOC), UV254, trihalomethane formation potential (THMFP), haloacetic acid formation potential (HAAFP) by 72.2%, 171.4%, 83.7% and 88.6%, respectively. Planting aquatic plants in surface wetlands will negatively affect the water quality of micro-polluted raw water, with the plants being an important source of increased DBP precursors in wetland effluent. The effluent properties were similar to those of SRNOM, and had a higher degree of aromatization and larger molecular weight than raw water. The increased DBP precursors were mainly fulic acid and humus with higher aromatic and molecular weight, which derived from the growth and metabolism of aquatic plants. Humic substances (HS) accounted for the highest proportion of DOM in this study, with the average molecular weight of HS increasing from 648 to 698 g·mol−1 as the DOM content increased. Results from this study are particularly applicable to the establishment of constructed wetlands planted with aquatic plants in the drinking water sources, and the DOM derived from aquatic plants in constructed wetlands may be important precursors in the subsequent water disinfection process.

Derosion Lattice Performance and Optimization in Solving an End Effect Assessed by CFD: A Case Study in Thailand’s Beach

Thailand’s beach had a severe coastal erosion problem at the end of rock dams called the “end effect”. One of the innovative solutions to solve this problem is to use the derosion lattice (DL). However, since the DL performance depends on installing conditions such as angle of attack, placement position, terrain, and climate, computational fluid dynamics (CFD) was applied to assess the end effect’s occurrence and optimize the performance of DL’s installation. Based on Khao Rup Chang’s condition, a suffered beach in Thailand was used as a case study, and a free surface flow simulation was performed in the transient state using ANSYS Fluent, a CFD software, which revealed water waves flow through the beach with and without the DL installation cases. Furthermore, the CFD-assessed results indicated that the angle of attack and placement position affected the DL performance as expected. In optimization, the 15° angle of attack with the DL placement adjacent to the rock dam was the proper condition. After being applied at the actual site, the DL can help reduce erosion, increase sedimentation, and solve the end effect with excellent performance.

Stability and accuracy of the weakly compressible SPH with particle regularization techniques

This paper proposes and validates two new particle regularization techniques for the Smoothed Particle Hydrodynamics (SPH) numerical method to improve its stability and accuracy for free surface flow simulations. We introduce a general form of the Dynamic pair-wise Particle Collision (DPC) regularization technique that we recently proposed in the context of the Moving Particle Semi-implicit (MPS) method in Jandaghian et al. (2021). The DPC coupled with the standard Particle Shifting (PS) technique has given rise to a hybrid approach that we propose to alleviate particle clustering issues in the free-surface and splashed regions. We validate the proposed techniques to four benchmark cases: (i) the oscillating droplet, (ii) the two-dimensional water dam-break, (iii) the two-dimensional water sloshing, and (iv) the three-dimensional water dam break against a rigid obstacle. We evaluate their impacts on the stability, accuracy and the conservation properties of the test cases. The qualitative and quantitative analysis of the results shows that despite its simplicity, the DPC technique is more effective in reducing the spatial disorder and capturing the impact events compared with the standard and the newly improved hybrid PS methods. Although the hybrid PS technique improves particle distribution at the free surface, it still suffers from the inconsistent implementation of the PS equation which unphysically increases the fluid volume and violates the conservation of potential energy in the long-term simulations. Overall, the conservative DPC algorithm proves to be a simple and efficient alternative regularization technique for simulating such highly dynamic free-surface flows.

Numerical simulation of the free surface flow passing two hydrofoils

In this paper, a numerical method based on potential flow theory is proposed to investigate the hydrodynamic interaction between two foils with free surface effect. The integral equation is solved using boundary element method. On foil surfaces, the impermeable boundary condition is satisfied. On free surface, nonlinear kinematic and dynamic boundary conditions are satisfied. A robust numerical model is proposed to avoid the complicated vortical interference between the two foils. A fully nonlinear scheme is developed for the numerical simulation. The proposed method is validated by extensive convergence studies. The hydrodynamic loadings on the foils are investigated in time domain. Two major quantitative findings are discussed. Firstly, the free surface elevation could be weakened significantly if the two foils are appropriately arranged. Secondly, the lifting force of the following foil varies periodically with the increase of the horizontal distance between the foils.

金属粉床積層造形プロセスに対する格子ボルツマン法とマルチフェーズフィールド法

A Multi-phase field lattice Boltzmann method for melting, gas/liquid flow and solidification in powder bed fusion process of Ni alloy additive manufacturing is developed. Improved lattice kinetic scheme is adapted for gas/liquid free surface flow simulation. High speed calculation is achieved by MPI&OpenMP hybrid parallelization. It is confirmed that this method has high capability to simulate the powder bed fusion process in detail.

A coupled level set/volume of fluid method for simulation of two-phase flow on unstructured grids

We present a fully coupled level set and volume of fluid method for free surface flow simulations on unstructured grids in two- and three-dimensions. The evolution of the level set function and the volume fraction are updated at each time step. The level set advection equation is solved by a least squares weighted residual method while the volume fraction advection is solved using an unsplit Eulerian-Lagrangian scheme. The reconstruction of the interface in the volume of fluid method is performed using the volume fraction information together with the normal vector obtained from the level set function. The reconstructed interface is then used to reinitialize the level set function. Thanks to the fully coupling of the two methods, the interface reconstruction is carried out efficiently and the mass conservation is preserved exactly. The proposed method is validated against several benchmarks and is coupled with the incompressible Navier-Stokes solver to solve two-phase flow problems. Numerical results show that the method is capable of resolving complex interface changes efficiently and accurately.

Coupling surface flow with high-performance subsurface reactive flow and transport code PFLOTRAN

Water exchange between the surface and subsurface is important for both water resource management and environmental protection. In this paper, we develop coupled surface and subsurface flow simulation capability in a parallel subsurface flow and reactive transport code PFLOTRAN. We sequentially couple the diffusion wave-based surface flow with the subsurface flow governed by the Richards equation in PFLOTRAN. These two flow domains are linked with a boundary condition switching method that ensures the continuity of pressure and flux at the surface-subsurface interface. We verify the coupled code against other existing hydrologic models and observation data using a number of numerical experiments. The coupled hydrological model exhibits good performance in strong parallel scaling tests. The new coupled surface and subsurface simulator significantly advance community simulation capability towards improving integrated hydrologic and biogeochemical understanding of complex systems such as watersheds and river corridors.

Remote sensing vs. field-based monitoring of agricultural terrace degradation

The degradation of agricultural terraces is considered a major challenge to soil and water conservation in steep-slope viticulture. Although terracing is a widespread conservation practice, its sustainability is threatened by adverse climatic and man-made conditions. Previous studies have shown the impact of terrace designs on the formation of runoff pathways, causing degradation processes on terrace platforms (e.g. sheet erosion) and walls (e.g. piping, landslides, collapse). This study evaluates a remote sensing versus a field-based approach to monitor hydrological processes responsible for terrace degradation, as tested in a north-Italian vineyard. The field-based approach was based on spatially measured Soil Moisture Content (SMC) using a Time Domain Reflectometry (TDR) instrument, which clearly revealed saturation hotspots around two damaged terraces in the study area. Moreover, these zones showed a particular cross-sectional SMC profile, with the highest saturation close to the terrace platform edges. The remote sensing approach was based on aerial imagery acquired by an Unmanned Aerial Vehicle (UAV) and photogrammetric reconstruction of the vineyard geomorphology, allowing terrain-based analysis and physical erosion modelling. In this approach, simulations indicated that terrace damages could be partly explained by the formation of preferential runoff pathways caused by the terrace design. This parallel methodology allowed a comparison of the merits and limitations of either approach, as done in light of published work. The occurrence of two SMC hotspots at terrace edges (and their non-typical cross-sectional profiles) could be better understood from simulated surface flow paths. While the causal relationship between heterogeneous soil saturation and terrace instability has been previously reported in literature, the novelty of the presented study is the use of topsoil SMC as an indicator of potential damages, favouring the scalability compared to fixed, local and often intrusive terrace sub-surface experiments. Remote sensing based approaches, however, tend to offer the most time-efficient solution on larger scales, and aerial acquisition of SMC distribution could thus potentially offer a powerful integrated methodology.

Assessing the land use/land cover and climate change impact on water balance on Tordzie watershed

Water resources management in watersheds require quantitative knowledge of it in time and space. Water availability in watersheds are influenced by land use/cover (LULC) and climate change. This study relate LULC and projected climate changes to water balance in Tordzie basin using climate scenario of RCP 4.5 with CCCMA Model. SWAT embedded in ArcGIS was used for the water availability assessment after calibration (2000–2003) and validation (2004–2006) using discharge from Tordzinu within Tordzie. The Nash-Sutcliffe Efficiency (NSE), Coefficient of regression (R2) and Percent bias (PBIAS) were performance evaluators employed to assess model suitability and validity on monthly time scale. The SWAT performance indicator values were 0.74, 0.74, −5.10% respectively for 2003 LULC and 0.88, 0.89 and + 0.30% for 2017 LULC. The simulated surface flow (SURF_Q) under the LULC scenarios increased by 24.65% and water yield (WYLD) decreased by 6.7%. The annual simulated water yield were 132.21 mm and 123.30 mm. We found LULC have significantly impacted the hydrology of Tordzie watershed. Projected water balance (2050) indicated increase in surface flow (19.00%) and decrease in ground water (36.40%), base flow (0.77%) and water yield (6.50%). This was linked to climate change. Further study of the watershed is recommended incorporating the water quality parameters.

A semi‐implicit stabilized particle Galerkin method for incompressible free surface flow simulations

SummaryA new particle Galerkin method is introduced to solve the Naiver‐Stokes equations in a Lagrangian fashion. The present method aims to suppress key numerical instabilities observed in the strong form Lagrangian particle methods such as smoothed particle hydrodynamics (SPH), incompressible SPH, and moving particle semi‐implicit for incompressible free surface flow simulations.It is well‐known that strong form Lagrangian particle methods usually rely on ad hoc particle stabilization techniques based on particle shifting, artificial viscosity, or density‐invariant condition due to some formulation inconsistency issues. In the present method, we introduce a momentum‐consistent velocity smoothing algorithm which is used to combine with the second‐order rotational incremental pressure‐correction scheme to stabilize the pressure field as well as to enforce the consistency of Neumann boundary condition. To further impose slip‐free or nonslip boundary conditions for the fluid flow, a penalty method which is free of ghost or dummy particles is developed. Finally, a particle insertion‐deletion adaptive scheme is proposed when the violent fluid flow is considered. Four numerical examples are studied to validate the accuracy and stability of the present method.

Performance of a zero-inertia model for irrigation with rapidly varied inflow discharges

The zero-inertia model is widely used for simulating surface flow in irrigation systems. This model is accurate when inflow discharge is constant. However, simulation of irrigation systems with rapidly varied inflow discharge is needed due to the development of real time control irrigation technology. Hence, the objective of this study is to validate the zero-inertia model with rapidly varied inflow discharge. For this purpose, twenty-three border irrigation tests at a range of inflow changes on different field slopes and roughness coefficients were conducted. Then, the sensitivity analyses of bed slope, infiltration parameters, and roughness coefficient were examined. The results indicate that the zero-inertia model predictions are in good agreement with field data in both advance/recession times and flow depths. The infiltration parameters were the most sensitive input variable of the zero-inertia model. The input variables have a more considerable impact on the recession phase than the advance phase. Keywords: zero-inertia model, rapidly varied inflow, border irrigation, sensitivity analysis DOI: 10.25165/j.ijabe.20201302.5228 Citation: Liu K H, Jiao X Y, Li J, An Y H, Guo W H, Salahou M K, et al. Performance of a zero-inertia model for irrigation with rapidly varied inflow discharges. Int J Agric & Biol Eng, 2020; 13(2): 175–181.

Small Arctic rivers mapped from Sentinel-2 satellite imagery and ArcticDEM

Small rivers (<30 m) are significant components of terrestrial river networks and remote sensing is a necessary tool to study them at the global scale. However, current global hydrography data products generally include only rivers that are wider than 30 m, neglecting smaller waterways and thus limiting our understanding of surface water processes, especially in remote areas. We present a new automated methodology to map two Arctic actively-flowing river networks (Kotuy and Coleen Rivers, with study areas of ~12,000 km2 and 10,000 km2, respectively), including small rivers as narrow as 10 m from Sentinel-2 multispectral satellite imagery and high-resolution ArcticDEM digital elevation data. First, preliminary river network masks were generated by using Gabor filtering and path opening morphological operations on Normalized Difference Water Index (NDWI) images. Second, ArcticDEM data were employed to simulate surface flow paths, and the resultant drainage networks were used to create river areas of interest (AOI) and subsequently eliminate non-water features outside the river AOI. Third, gaps along remotely sensed small river channels were filled using the ArcticDEM-modeled drainage networks, yielding continuous river networks with high spatial resolution. We compared the 10 m Sentinel-ArcticDEM merged River Network (SARN) with the National Hydrography Dataset (NHD) and four 30 m Landsat-derived hydrography data products (GSW, GRWL, FROM-GLC 2017, and G3WBM). We conclude: (1) SARNs have similar quality to the >1st order NHD (>70% of NHD streams appear in SARNs). (2) At a reach scale, SARNs include more small rivers with the drainage densities at least ~4.5 times larger than Landsat-derived hydrography data products. Similarly, coupling ArcticDEM data with 30 m Landsat satellite images increases resultant drainage densities approximately three-fold. (3) At a catchment scale, merging remotely sensed river networks with ArcticDEM-modeled drainage networks significantly improves river connectivity (defined as the longest connected river length) with at least a ten-fold increase over the other hydrography data products examined here. In sum, merging high-resolution Sentinel-2 imagery with ArcticDEM data enable effective, continuous mapping of complex fluvial drainage patterns of Arctic rivers.

DEVELOPMENT AND APPLICATION OF A SEASONAL FURROW IRRIGATION MODEL (SFIM)

AbstractIf furrow irrigation is properly designed and implemented, this method would be one of the best surface irrigation systems. To achieve high irrigation efficiency and uniformity in surface irrigation, the use of simulation models is inevitable. The purpose of this study was to develop a seasonal furrow irrigation model to simulate the whole irrigation season (every irrigation event). The model called ‘SFIM’ was developed using the FORTRAN programming language. SFIM consists of four sub‐models to simulate surface flow, subsurface flow, crop yield, water productivity and irrigation evaluation indices. Three data sets of furrow irrigation for maize crop production in the Alborz Province of Iran (College of Agriculture and Natural Resources and Seed and Plant Improvement Institute farms) were used for evaluation of the proposed model. Average relative error of the model ranged from 11.5 to 17.2%, 7.5 to 11.3% and 6.8 to 9.0% in estimating infiltrated water volume, crop yield and water productivity, respectively. The model could also well simulate temporal soil moisture variations and water stress in the root zone. As a consequence, the SFIM model could successfully simulate all irrigation events during the maize‐growing season. © 2020 John Wiley &amp; Sons, Ltd.

Performance of a zero-inertia model for irrigation with rapidly varied inflow discharges

The zero-inertia model is widely used for simulating surface flow in irrigation systems. This model is accurate when inflow discharge is constant. However, simulation of irrigation systems with rapidly varied inflow discharge is needed due to the development of real time control irrigation technology. Hence, the objective of this study is to validate the zero-inertia model with rapidly varied inflow discharge. For this purpose, twenty-three border irrigation tests at a range of inflow changes on different field slopes and roughness coefficients were conducted. Then, the sensitivity analyses of bed slope, infiltration parameters, and roughness coefficient were examined. The results indicate that the zero-inertia model predictions are in good agreement with field data in both advance/recession times and flow depths. The infiltration parameters were the most sensitive input variable of the zero-inertia model. The input variables have a more considerable impact on the recession phase than the advance phase. Keywords: zero-inertia model, rapidly varied inflow, border irrigation, sensitivity analysis DOI: 10.25165/j.ijabe.20201302.5228 Citation: Liu K H, Jiao X Y, Li J, An Y H, Guo W H, Salahou M K, et al. Performance of a zero-inertia model for irrigation with rapidly varied inflow discharges. Int J Agric & Biol Eng, 2020; 13(2): 175–181.