Flow Pathlines Research Articles

Computational Fluid Dynamic Analysis of Water Flow Through Nozzle of a Gravimetric Measuring Method System

The gravimetric measuring method incurs errors and uncertainties in calibration, originating from various sources, with the diverter valve being one of the most significant. For optimal operation, the output flow from the diverter valve should form a jet in a thin, rectangular sheet form to ensure a low uncertainty value. The current work explores different scenarios in the configuration of an upstream diverter valve installation to determine its effect on velocity profile and flow path line at the nozzle outlet. The analysis is conducted using CFD Fluent edition 2023, varying operational conditions and nozzle geometry. In the results section, a pressure drop along the nozzle at different velocities as well as uniformity in velocities vectors and pressure magnitude at outlet nozzle, are presented.

Flow around an Aircraft Model—Comparison between Hydrodynamic Tunnel Tests and Computational Fluid Dynamics Simulations

This paper presents a comparative analysis of the results obtained using the computational fluid dynamic method and a hydrodynamic tunnel. The aerodynamic properties of the General Dynamics F-111 Aardvark aircraft were subjected to both qualitative and quantitative assessment. In both cases, the same geometric model of the aircraft was used. For the hydrodynamic tunnel tests, the model was 3D printed, while for the CFD simulations, the geometry was imported into ANSYS Fluent 2021 R2 software. During quantitative studies, aerodynamic characteristics, including the coefficients of lift, drag, and pitching moment for the aircraft, were determined over a wide range of angles of attack. In turn, flow field images and pathline visualization of the vortex were obtained following qualitative studies. The comparative analysis showed that high consistency between the simulation and experimental results was achieved.

Effect of atomizing gas type on kerosene spray combustion using gas-blast atomizer: A comparative numerical study

In order to attain optimal combustion efficiency, minimal pollutant emissions, and reliable stability in gas turbines, a computational model was developed to study the combustion and atomization characteristics of liquid fuel (Kerosene). Seven different atomizing gases were considered, namely, air, ammonia, hydrogen, natural gas, superheated steam, oxygen, and nitrogen. The work aims to investigate the potential of hydrogen in contrast to the other atomizing gases, in minimizing pollutant concentrations in the combustion exhaust considering the associated cost implications. A 3D cylindrical combustor with a gas blast atomizer was employed while maintaining a constant air swirl number. The total thermal load across all tests was kept constant by varying the liquid kerosene flow rate. The simulations analyzed various parameters in order to address the combustion characteristics, such as reverse flow zone (RFZ), recirculated flow mass ratio, flow pathlines, temperature maps, centreline axial temperatures, outlet temperatures, species concentrations, and droplets characteristics. The results showed that the flame temperature reached its peak when hydrogen was utilized. When using combustible atomizing gases, the CO and CO2 concentrations at the exit of the combustor tube were generally lower. However, the CO concentration is notably higher when air is employed, unlike other gases such as nitrogen, oxygen, and natural gas, which showed decreased CO levels. Remarkably, the CO concentration experiences a significant decline of about 98% when natural gas is utilized. The average concentration of NOx is highest when oxygen and hydrogen are used as atomizing gases, but it experiences a significant decrease of approximately 75% when air is employed instead. It can be deduced that different gases such as hydrogen gas have a possibility as an option and sustainable atomizing gases on spray performance.

Effect of underground structures on groundwater residence time distributions in confined aquifers

Anthropic pressure and property economics lead to the vertical development of urban space, but groundwater residence time can be influenced by the urban underground structures constructed in it. Meanwhile, groundwater residence time is critical to the renewability of aquifers and the vulnerability to contamination. The effects of underground structures on local and regional residence times for confined aquifers remain unclear. This paper presents novel analytical solutions for groundwater residence time distributions (RTDs) affected by impervious underground structures in confined aquifers under three boundary conditions (BCs), namely the fixed-flux BC, the fixed-head BC, and the diffuse-leakage BC, respectively. The analytical solutions show a good agreement with numerical results for barriers fully obstructing the aquifer. For barriers partially obstructing the aquifer, discrepancies can be found between the analytical and the numerical RTDs due to the hydrodynamic dispersion of flow pathlines. Nevertheless, the calculated mean residence time (MRT) presents a good correspondence with numerical results for all parameter realizations, indicating that analytical solutions can be used to estimate regional MRT even for three-dimensional flow fields. Global sensitivity analysis (GSA) using Sobol’ method identifies influential parameters for residence times and underlines the importance of boundary conditions in determining the MRT. Finally, two successful applications of the analytical solutions in Barcelona aquifers indicate that the modification in residence times does not correspond to the modification in hydraulic heads. Overall, the proposed analytical solutions successfully quantify the barrier effect on residence times and prove to be useful in supporting underground space exploitation, and aiding the environmental risk assessment.

Numerical modeling as a support tool for groundwater permits in the state of Bahia, Brazil

The western region of Bahia State is an important agricultural frontier in Brazil, generating a large increase in requests for groundwater usage in the last decades, mainly through large capacity water wells tapping the Urucuia Aquifer System (UAS). This study aims to develop a groundwater numerical model using the Visual MODFLOW software and the additional packages MODPATH and ZONEBUDGET to evaluate the effects of intensive groundwater pumping in eight possible scenarios of two areas (Central and Eastern) in the Alto Grande - São Desidério rivers sub-basin. Drawdown ranging from 4 to 20 m was observed in the different areas and scenarios. The analysis of the local flow path lines showed that the wells have an area of influence that captures part of the groundwater flow. The water balance indicated that the total volume pumped in the sub-basin did not reach 10% of the recharge in any scenario, considering the entire model domain. The high concentration of irrigation pumping wells in restricted areas resulted in a significant impact on the aquifer, reaching up to 84.6% of the local recharge, a value that is far above what is considered sustainable for the region. Results show that the eastern area is more susceptible to drawdown and changes in flow path lines by pumping. The applied method has proven to be useful to predict the effects of water abstraction on the aquifer before the implementation of projects, improving water resources management. Long-range forecasts and taking into account possible climate changes are also some of the advantages of the method, though it depends on reliable field hydrological and climate data.

Conduit design with expanding diameter for enhanced flow

Conduits are commonly used for treating lesions in arteries and veins. The conventional stents are cylindrical in shape, which increases flow resistance with length. This study presents a design of stents and conduits where the conduit caliber expands gradually to reduce resistance while avoiding flow separation. Inflow was provided from a header tank at two different pressures (i.e., 10 and 25 mm Hg pressure) into a cylindrical or expanding conduit. The initial conduit calibers were 2-, 3-, 4-, and 5-mm and 160-, 310-, and 620-mm lengths in each case. The flow rates of expanding caliber conduits (at a rate of r4–6/cm where r is the initial conduit radius) were compared to traditional cylindrical conduits of constant radius. The expanded caliber yields a significantly increased flow of 16–55% for R4/L expansion, 9–44% for R5/L expansion, and 1–28% for R6/L expansion. Simulated flow models using computational fluid dynamics (CFD) were used to validate and expand the experimental findings. Flow separation was detected for certain simulations by flow pathlines and wall shear stress (WSS) calculations. The results showed that a caliber expansion rate of r6/cm is the optimal rate of expansion for most potential applications with minimum flow separation, lower resistance, and increased flow.

Simulating the Flood Limits of Urban Rivers Embedded in the Populated City of Santa Clara, Cuba

Floods are a natural phenomenon that cause damage to structures and property as well as negatively affect human life. Assessing the extent, speed, power, and depth of flooding has always been a challenge for water resource planners. This research developed a hydraulic simulation model for the Cubanicay and Bélico urban rivers embedded in the city of Santa Clara, Cuba. The methodology was based on a one-dimensional model of the Hydrological Engineering River Analysis System (HEC-RAS) and GIS-based methods. The HEC-RAS model (Beta) and three modeling flood tests for scenarios of 1% (100 years), 2% (50 years), and 10% (10 years) of probability for hydrometeorological events were analyzed. Bank lines, flow path lines, and cross-section cut lines were extracted from Digital Elevation Models. Manning’s roughness coefficients were considered for the channel morphology and soil typology. The flood Beta model results were accurate with a difference of ±0.10 m considering the water footprint found in the field. The results showed that the areas near the control section 2 + 87 presented a high risk of flooding. The flood limit map for urban areas could be an important tool for researchers, planners, and local governments for risk assessment and to develop evacuation plans and flood mitigation strategies in order to reduce human and economic losses during a flood.

Groundwater Vulnerability and Delineation of Protection Zones in the Discharge Area of a Karstic Aquifer—Application in Agyia’s Karst System (Crete, Greece)

This work represents a contribution to the protection techniques of karst aquifers against groundwater pollution. The paper sets out the methodology being introduced for the protection of the karstic system that gives rise to five (5) major groups of springs and supplies fourteen (14) pumping wells near Agyia Chania (Crete, Greece). Starting from a geological and hydrogeological survey of the area, the work presents a vulnerability assessment of the karstic aquifer based on the application of three index-based methods (EPIK, PRESK and DRISTPI). The protection zones for the discharge area of the aquifer were delineated through an integrated geomorphological approach and groundwater flow modeling. At first, the risk of polluting substances migration from ground surface to groundwater was considered based on the spatial distribution of vulnerability. Following this, the vulnerability was evaluated in the saturated zone, where the attenuation mechanisms of contaminants were reducing due to the raised flow velocity. The groundwater flow and contaminant transport processes was considered using the MODFLOW code. Next, the data from the vulnerability mapping and the groundwater flow simulation were merged into an integrated assessment to delimit the protection zones for the water abstraction points. The vulnerability assessment outlines zones of high vulnerability in the SE part of the area, far away from the discharge zone of the aquifer and the water abstraction points. These zones are associated with an intensive infiltration process via carbonate formations. Protection Zone I was delineated 20 m around the water abstraction points, and it should be excluded from any anthropogenic activity. Protection Zone II coves part of the very high and high vulnerability zones defined by the DRISTPI method (located upwards of the water abstraction points), as well as an area downwards of springs and wells, where the flow path lines which demonstrate the subsurface travelling time of 50 days are projected to the ground surface. Protection Zone III extends outside Zone Ι and Zone ΙΙ, up to the limits of the hydrogeological or hydrological basin, whichever is larger. It includes the entire capture zone (i.e., the surface and underground catchment area) that feeds the water abstraction points. In this manner the protection zones include the entire contributing area to water abstraction points, not just the ground surface recharge zone.

Numerical investigation of seepage characteristics of propped fracture in coalbed methane reservoirs

The investigation of the pore structure characteristics and the effect on fluid seepage in propped fractures are important considerations for improving coalbed methane (CBM) production and optimizing CBM extraction systems. In this paper, a numerical model was established to study the pore structure characteristics and distribution of fluid pressure, velocity and pathline fields of propped fractures. The results showed that, with the increase of the closure stress, the porosity decreased linearly while the effective pore connectivity ratio first increased, then decreased. The best flow conductivity of the fracture was achieved at the closure stress of 12.67 MPa. In addition, there were disparities in the pore distribution of the different layers due to the uneven transfer of the closure stress from top to bottom. Compared to the top and bottom layers, the effective pore connectivity ratio and fluid pressure were significantly smaller in the middle layer, while the flow velocity and pathline length were larger. The top and bottom layers were the main fluid seepage channels. The results of this study can provide a theoretical basis for CBM production prediction and real-time quantitative optimization of CBM extraction systems.

Numerical study of kerosene spray and combustion characteristics using an air-blast atomizer

In this study, a computational model for a cylindrical combustor with an air-blast atomizer was created to investigate the effect of changing air to liquid mass ratio (ALR) on spray characteristics without combustion and the effect of changing ALR on combustion characteristics under different swirl numbers with constant kerosene fuel mass flow rate using computational fluid dynamics (CFD) code. The study aim is to define the ALR at which the pollutants concentrations at combustion exhaust will be the least. Eight values of ALR were considered and these include 0.3, 0.5, 0.7, 0.9, 1.0, 1.2, 1.4 and 1.5. The cold spray characteristics including the number of droplets, Sauter Mean Diameter, droplets penetration length and droplets contours were obtained in addition to combustion characteristics that were studied by describing the reverse flow zone (RFZ) boundary, flow pathlines, temperatures maps, outlet temperatures at combustor exit and species concentrations. The results indicate that increasing ALR and consequently spray droplet diameter decrease does not always translate into superior emissions performance and it depends on several parameters including swirling intensity where the modernistic capabilities of CFD code including flow visualization and calculated recirculated mass flow ratio are used to justify the reasons behind this exceptional behavior. In addition, the results show that the spray Sauter Mean Diameter decreases by increasing ALR but the droplet diameter reduction effect was steeper at lower ALR than higher ones. The length of the RFZ is decreasing with the increase of ALR and shifts upstream closer to the combustor swirler. The recirculated flow mass ratio and the outlet average temperature are decreasing with the increase of ALR.

Study of Coronary Atherosclerosis Using Blood Residence Time.

Computational fluid dynamic-based modeling is commonly used in stenosed and stented coronary artery to characterize blood flow and identify hemodynamics factors that could lead to coronary stenosis. One such factor is the residence time (RT), which is important for investigating stenosis and restenosis progression. The current method to calculate RT, known as the relative residence time (RRT) method, does not provide the original scale of RT and only provides a relative value. We recently introduced a novel method, designated as RT method, based on developing the advection-diffusion equation with a scalar to calculate the absolute residence time. The goal of this study was to compare both methods. Our results show that both could detect regions with a high risk of stenosis and restenosis, but the RT method is also able to show the recirculation zone using pathlines in the lumen and quantify actual RT. Moreover, RT method also provided blood flow pathlines, and is correlated to wall shear stress (WSS), oscillatory shear index (OSI), RRT, and Localized Normalized Helicity (LNH) which are other critical factors to gauge stenosis severity and assess stenting in bifurcations coronary.

86057 High Screening Efficacy Using Wearable Seismocardiography to Identify Aortic Valve Disease Patients, Potential to Tailor MRI Exams to Patient Needs

ABSTRACT IMPACT: A single seismocardiography (SCG) parameter has been shown to accurately classify aortic valve disease (AVD) status in healthy controls and AVD patients. This could support development of SCG as a quick, inexpensive screening tool to better tailor MRI examination to patients’ needs. OBJECTIVES/GOALS: MRI is used commonly for monitoring of aortic valve disease (AVD), but it has high costs. We hypothesize that energy in seismocardiograms (SCG)’‘ signals from chest surface vibrations’‘ is different between healthy controls and AVD patients, and we evaluate potential efficacy of using SCG to recommend MRI only for patients with flow abnormalities. METHODS/STUDY POPULATION: With IRB approval, 45 healthy control subjects (47 ±18years, 18 female) and 9 patients (63 ±16years, 2 female) with aortic valve disease history and known flow abnormalities were recruited. SCG signals were acquired supine, immediately prior to MRI of thoracic aortic blood flow at 1.5T with a time-resolved phase contrast (4D Flow) sequence.The SCG was processed to calculate late-systole high-frequency (120-240Hz) RMS energy. MR velocity images were analyzed to measure peak velocity and trace pathlines of flow.Screening efficacy of the SCG energy metric was assessed, with hypothesis testing for differences in energy level distributions between controls and patients, and receiver-operator characteristic (ROC) analysis was used to calculate rates of correct/incorrect classification of disease. RESULTS/ANTICIPATED RESULTS: Healthy subjects had coherent flow pathlines through the aortic arch and mid-ascending aorta peak velocities of 106 ±21cm/s (cohort mean ±standard deviation). All valve disease subjects had flow abnormalities, such as jetting flow near the valve or swirling through the arch, as visualized by pathlines. Patients’ peak mid-ascending aorta velocities were 167 ±69cm/s. The SCG energy for healthy controls was significantly different than that of valve patients (-5.6 ±0.3dBmm/s/s vs. -4.0 ±1.2dBmm/s/s respectively; p<0.001). Thresholding SCG energy to distinguish patients from controls correctly classifies subjects with a high true-positive rate and low false-positive rate. The ROC for this classification has area-under-curve 0.956. DISCUSSION/SIGNIFICANCE OF FINDINGS: A high potential screening efficacy was observed using a single, linear SCG metric to identify AVD patients with flow abnormalities. If used to complement MRI surveillance protocols for AVD, this method has potential to serve as a quick, inexpensive tool for better tailoring MRI exams to patient needs.

Study of Flow Field Inside a Can Combustor for Micro Gas Turbine Engine Under Nonreacting Flow Conditions

Generally, micro gas turbines are in the range of 15 to 300 kW. However, recent applications in unmanned aerial vehicles (UAVs) and polygeneration require a small micro gas turbine. So, here a small swirl combustor designed for micro gas turbine engine of capacity less than 1 kW is analyzed under nonreacting flow conditions. Simulations have been carried out to study the flow field inside the can combustor. Flow field characteristics, like velocity, path lines, turbulent intensity and total pressure loss are studied. The total pressure loss across the combustor is also measured experimentally and compared with that of simulation results. Good agreement is achieved between experimental and numerical results. The combustor total pressure drop was found to be negligible in the range of 0.002 to 0.06% at an inlet velocity ranges from 1.7 to 10.19 m/s. Flow pattern indicates a strong swirling pattern and strong interaction between the secondary air entrainment inside the flame tube.

OUP accepted manuscript

Abnormal helical flow (HF) in the aortic arch has been proposed as a causative factor for aortic dilatation and aortic dissections (ADs). Patients with type B AD present a high prevalence of type III arch configuration, which comprises recognized anatomic AD risk factors. Our aim was to assess whether the type III arch configures a consistent secondary HF pattern.We employed computational fluid dynamics to compare HF features associated with type I-III arches. The intra-aortic blood flow pattern was regionally assessed through the Modified Arch Landing Areas Nomenclature (MALAN) for planning endovascular aortic repair. Aortic flow pathlines were extracted from the systolic aortic velocity field and objectively characterized through intrinsic shape indices of absolute curvature |κ| and absolute torsion |τ|. Absolute local normalized helicity was computed and mapped on aortic flow pathlines.The tendency of aortic flow pathlines to bend and rotate exacerbated in the isthmus of type III arch (MALAN 3/III), where the highest |κ| values (P < 0.0001) were paralleled by the lowest |τ| values (P = 0.010), demonstrating the persistence of a high rotational HF heavily insisting on 3/III. In 3/III area, local normalized helicity was higher than both 3/I and 3/II (P = 0.053).Type III arch configuration is associated with a specific, consistent and abnormal secondary HF pattern, which may account for its high prevalence in patients with type B AD.

Numerical investigation of the accuracy of particle image velocimetry technique in gas-phase detonations

We numerically investigate the accuracy of the Particle Image Velocimetry (PIV) technique for the flow characterization in high-speed, compressible regimes, in particular in gas-phase detonations. We carry out synthetic PIV reconstruction of the flow field in a two-dimensional, planar detonation propagating under atmospheric conditions and modelled using single-step Arrhenius kinetics. The flow is uniformly seeded with monodispersed Al2O3 particles with sizes 50 and 200 nm, along with initially co-located massless Lagrangian tracer particles. The effect of massive particles on the detonation speed and thermodynamic state of the flow is investigated and is found to be negligible. We further assess the ability of massive particles to sample the flow field and while it is found that 50 nm particles sample the flow field better than the 200 nm ones, they also exhibit significant clustering. By comparing the trajectories of massive particles with those of massless tracers, it is shown that almost all massive particles rapidly diverge from the actual flow pathlines. Finally, we quantify the accuracy of the PIV reconstruction of the velocity field in comparison with the actual velocity field in the numerical simulations. It is shown that while PIV is generally capable of capturing the bulk flow features in the streamwise direction, its accuracy is not sufficient to characterize the transverse velocity component or velocity fluctuations.

Application of new HEC-RAS version 5 for 1D hydrodynamic flood modeling with special reference through geospatial techniques: a case of River Purna at Navsari, Gujarat, India

Floods are among the extreme natural events which result in catastrophic damage to properties and adversely effects communities. To curb and manage the effects of such events, the decision-makers and disaster management authorities require dependable data in terms of flood depth, discharge, magnitude, and special datasets. The low lying areas of Navsari city was inundated in the floods of 2002 and 2003. This study aims to use the latest version of HEC-RAS for 1D hydrodynamic flood modelling of Purna river in Navasari city, Gujarat, India, with special reference to geospatial techniques. This study is aimed to demonstrate the geospatial analyzing capabilities of HEC-RAS v5. For the purpose of flood modeling, the river data such as bank lines, flow path lines, cross-section cut lines are extracted from Cartosat-1 DEM (Digital Elevation Model). Steady flow analysis is carried out for the simulation of a 1D hydrodynamic model. The outcome obtained from the model is in the form of water depth, which can be observed in the geospatial HEC-RAS mapper window. The flood depth maps for the 2002 and 2004 flood events are generated, which indicate that the low lying areas of Navsari city near Jalalpore and Viraval are susceptible to flooding when the discharge in the river exceeds 8836 m3/s. The accuracy of the model is calculated by comparing the simulated data with the observed data for the above-mentioned flood events. The results obtained from the 1D models are promising and accurate.

Particle Tracking Using Dynamic Water-Level Data

The movement of fluid particles about historic subsurface releases is often governed by dynamic subsurface water levels. Motivations for tracking the movement of fluid particles include tracking the fate of subsurface contaminants and resolving the fate of water stored in subsurface aquifers. This study provides a novel method for predicting the movement of subsurface particles relying on dynamic water-level data derived from continuously recording pressure transducers. At least three wells are needed to measure water levels which are used to determine the plain of the water table. Based on Darcy’s law, particle flow pathlines at the study site are obtained using the slope of the water table. The results show that hydrologic conditions, e.g., seasonal transpiration and precipitation, influence local groundwater flow. The changes of water level in short periods caused by the hydrologic variations made the hydraulic gradient diversify considerably, thus altering the direction of groundwater flow. Although a range of groundwater flow direction and gradient with time can be observed by an initial review of water levels in rose charts, the net groundwater flow at all field sites is largely constant in one direction which is driven by the gradients with higher magnitude.

Experimental and numerical study of smoke behavior in high-rise stairwells with open and closed windows

This study numerically and experimentally investigates the transport phenomena in buoyancy-driven smoke inside stairwells in a high-rise building. Hot smoke is supplied at the bottom of a small-scale, 2-m high stairwell prototype, and the smoke velocity and temperature are measured and compared with the corresponding numerical results. For all-windows-closed cases, the Fire Dynamics Simulator (FDS) model is used to predict the smoke velocity and temperature fields, which are found to be in good agreement with the experimental data. Obstruction caused by the stairs is observed to slow the smoke flow, which results in staggering and repeated vortical flows in all stairwells, confirmed by flow visualization. The flow path lines and vortex formation of the smoke inside the stairwells are visualized using the laser-induced fluorescence (LIF) method; these vortical structures also corresponded to the results of FDS simulation. Furthermore, the effect of heating power (Q) is investigated in the range of 60–180 W for experiments and 1–4 kW for simulations. Both temperature and velocity increase with Q. Having one open window at various building heights is shown to have small effect on the overall smoke temperature, although having many open windows causes a temperature drop owing to the inflow of fresh, cool air. Having one open window at various building heights slightly slows the smoke velocity, although the velocity is significantly decreased when many windows are open. Therefore, the intake of fresh air slows the overall smoke dynamics. Moreover, the effect of Q in the range of 2–20 MW over building heights of 60, 120, and 240 m is numerically simulated. The rate at which the smoke reaches high elevations is determined for all-windows-closed and all-windows-open cases based on our parametric studies. The smoke rise time (t) is shown to be proportional to ~ Q-1/3 for all building heights, which is the same time scale as the one predicted by the plume theory. However, because of the complex internal geometry of confined buildings including stairwells and corridors, the magnitude of the smoke rise time for the building is much larger than that predicted by the plume theory. Therefore, the current experimental and numerical findings may be useful as design guidelines for building safety engineers.

Critical Analysis of Hepatic Clearance Based on an Advection Mass Transfer Model and Mass Balance

The relationship between liver blood flow rate and hepatic clearance has been derived and validated based on the constitutive principle of mass conservation using an advective mass transfer model for bivariate concentration, Ci (x, t). Metabolic elimination continuously diminishes along the blood flow path line, corresponding with the concentration gradient. Because of the constraint introduced by constant blood velocity, x and t are not independent variables. This requires the introduction of a new factor called the dwell time, which accounts for the time a drug is retained in the liver. First-order or saturable drug metabolism is dependent on perfusate drug concentration and the dwell time. A new extraction factor is explicitly identified as E = ln Cin/Cout. Because the isolated organ perfusion model described here is validated, it provides a basis for drawing inferences and exploring underlying features, mechanisms, and principles on which this model is based. In the conventional model, these underlying constitutive principles are unavailable. The concentration-time profile of a physiological-based elimination network is found to be inconsistent with the profile described by a pharmacokinetic model. For this reason, among others discussed, physiological-based models are incompatible with pharmacokinetic models and therefore cannot be used to explain systemic pharmacokinetic behavior.

The FEM model of groundwater circulation in the vicinity of the Świniarsko intake, near Nowy Sącz (Poland)

Abstract Modern hydrogeological research uses numerical modelling, which is most often based on the finite difference method (FDM) or finite element method (FEM). The present paper discusses an example of application of the less frequently used FEM for simulating groundwater circulation in the vicinity of the intake at Świniarsko near Nowy Sącz. The research area is bordered by rivers and watersheds, and within it, two well-connected aquifers occur (Quaternary gravelly-sandy sediments and Paleogene cracked flysch rocks). The area was discretized using a Triangle generator, taking into account assumptions about the nature and density of the mesh. Rivers, wells, an irrigation ditch and infiltration of precipitation were projected onto boundary conditions. Conditions of groundwater circulation in the aquifer have been assessed based on a calibrated model, using water balance and a groundwater level contour map with flow path lines. Application of the program based on FEM, using smooth local densification of the discretization mesh, has allowed for precise mapping of the location of objects that significantly shape water circulation.