3D Flow Research Articles

On the emergent scale of bedrock groundwater contribution to headwater mountain streams

We investigated the contribution of bedrock groundwater to streamflow as a function of catchment scale in a headwater stream. Synoptic surveys were conducted during hydrologically important periods of the year using multiple environmental tracers in stream water, soil water, and bedrock groundwater, along a first-order montane stream, in west-central Montana. Sampled analytes included 222Rn, used to constrain total subsurface flux, and major and minor elements, used in end-member mixing analysis (EMMA) to identify the contributions of soil and bedrock groundwater to the stream. Partitioning between soil-derived and bedrock-derived groundwater was then analyzed as a function of the incremental and accumulated sub-catchment sizes. Radon results indicated that subsurface water contributions accounted for the majority of streamflow at all surveyed times. EMMA results revealed that the bedrock groundwater contribution to streamflow varied between 26% during peak snowmelt and 44% during late summer. Streamflow generation was dominated by soil groundwater contribution along the entire reach, but the bedrock groundwater contribution increased consistently with accumulated sub-catchment size. However, groundwater contributions were not well-correlated with incremental sub-catchment size. The scale at which increased bedrock groundwater discharge can be correlated with sub-catchment size appears to be >1 km2 for our study. Our results are consistent with a conceptual model where streamflow is predominantly generated by a 3D subsurface nested flow system. Local subsurface heterogeneities control the stream source at local scales but begin to average out at scales >2 km2. Our study indicates that, while soil groundwater is the dominant source, bedrock groundwater remains an important and predictable contributor to streamflow throughout the year, even in a snow-dominated, mountainous headwater catchment.

Hybrid Nanofluid Thin-Film Dynamics of [PVA/MoS2+Cu]HNF: Synthesis, Characteristics and 3D Electromagnetic Flow Simulation via Variant Thickness Surface

This work aims to study the thermal features of three-dimensional hybrid nanofluid flow in the electromagnetic radiative flow of [PVA/MoS2+Cu]HNF via surface with variant thickness. Microporous structure thin films are fabricated from [PVA/MoS2+Cu]HNF via a physical vapor deposition (PVD) methodology. This study considered the existence of slippery speed and jumping heat constraints. Copper and molybdenum disulfide nanoparticles are suspended in polyvinyl alcohol (PVA) to form a hybrid nanofluid. Controlling equations are streamlined to ordinary differential equations and are resolved numerically by utilizing the NDSolve function in Mathematica. The implications of various parameters like nanoparticle volume size, radiative parameter and magnetic force are investigated, and outcomes are graphically provided. Studio 7.0 application with TDDFT/DMol3 is utilized to analyze molecular structures and conduct frequency computations for crystal modes and isolated molecules. DFT-Gaussian09W vibration values are juxtaposed with the experimental data about either the structural or optical aspects. The main outcomes are indicated by the isolated molecule of the polymer [PVA]iso and composite [PVA/MoS2+Cu]iso exhibiting a bandgap of 5.415 eV and 1.772 eV, respectively. The magnetic field reduces hybrid nanofluid flow velocity owing to the Lorentz force, which opposes fluid motion. A surge in radiative heat flux (RHF) significantly raises the nanofluid temperature.

On the geometry of Hamiltonian flow in 2D

On the geometry of Hamiltonian flow in 2D

Dynamic characteristic comparison between 1D model and 3D flow coupling with moving part model of liquid rocket engine flow regulator

Dynamic characteristic comparison between 1D model and 3D flow coupling with moving part model of liquid rocket engine flow regulator

1D thermoembolization model using CT imaging data for porcine liver

Innovative therapies such as thermoembolization are expected to play an important role in improving care for patients with diseases such as hepatocellular carcinoma. Thermoembolization is a minimally invasive strategy that combines thermal ablation and embolization in a single procedure. This approach exploits an exothermic chemical reaction that occurs when an acid chloride is delivered via an endovascular route. However, comprehension of the complexities of the biophysics of thermoembolization is challenging. Mathematical models can aid in understanding such complex processes and assisting clinicians in making informed decisions. In this study, we used a Hagen-Poiseuille 1D blood flow model to predict the mass transport and possible embolization locations in a porcine hepatic artery. The 1D flow model was used on imaging data of in-vivo embolization imaging data of three pigs. The hydrolysis time constant of acid chloride chemical reaction was optimized for each pig, and leave-one-out-cross-validation (LOOCV) method was used to test the model’s predictive ability. This basic model provided a balanced accuracy rate of for identifying the possible locations of damage in the hepatic artery. Use of the 1D model and experimental data provides an insight that using immiscible two-phase flow would better approximate the globular behavior seen.

Thermal Performance Characterization Of Dry Gas Seals In a sCO2 Compressor

Abstract Commercially available dry gas seals (DGS) are the seal-of-choice for shaft-end sealing locations in compressors used in the oil and gas industry, and supercritical CO2 power cycles. DGS reliability is tied to how well the 2 to 7 micron gas/supercritical fluid film is sustained under varying pressure, thermal, and speed conditions. Recent sCO2 turbomachinery development efforts have experienced a couple of catastrophic DGS failures at the compressor shaft-end locations. A suspected root cause of these DGS failures is thermal deformations caused by the excessive windage heating expected with the supercritical CO2 working fluid when the compressor operates at high pressures and high rotational speeds. In this paper, we investigate the thermal behavior of the DGS operating in a typical sCO2 compressor. Specifically, we present test data on a specially instrumented, commercially available DGS operating in the GE-SwRI sCO2 compressor operating under various mission points. Test data shows higher than expected temperatures (about 190 deg C) in the cavities surrounding the DGS, which provides useful insights to turbomachinery designers for designing seal cavities. Furthermore, we compare the measured temperatures with the predictions of a steady-state thermal model of the GE-SwRI sCO2 compressor. The thermal model uses a 1D flow advection network with cavity swirl solvers, windage and heat transfer coefficients for sCO2 flow exchanging heat with the surrounding structure. The predictions of the thermal model match reasonably well with the measured temperature data, thereby providing validation to the novel sCO2 thermal modeling assumptions.

Groundwater Recharge Assessment and Recharge Zonation of the Intermontane Groundwater Basin, Chiang Mai, Thailand, Using a Groundwater Flow Model and Stable Isotopes

Urbanization, escalating agriculture, tourism, and industrial development in the Chiang Mai–Lamphun groundwater basin in northern Thailand have increased water demand, causing widespread groundwater extraction. Over the past few decades, there has been a rapid, unrecoverable steady drop in groundwater levels in several areas in Chiang Mai and Lamphun provinces. This study employed hydrogeological investigations, hydrometeorological data analyses, stable isotopic analysis (δ18O and δ2H), and groundwater flow modeling using a 3D groundwater flow model (MODFLOW) to quantify groundwater recharge and delineate important groundwater recharge zones within the basin. The results showed that floodplain deposits exhibited the highest recharge rate, 104.4 mm/y, due to their proximity to rivers and high infiltration capacity. In contrast, younger terrain deposits, covering the largest area of 1314 km2, contributed the most to total recharge volume with an average recharge rate of 99.8 mm/y. Seven significant recharge zones within the basin, where annual recharge rates exceeded 105 mm/y (average recharge of the entire basin), were also delineated. Zone 4, covering parts of densely populated Muaeng Lamphun, Ban Thi, and Saraphi districts, had the largest area of 330 km2 and a recharge rate of 130.2 mm/y. Zone 6, encompassing Wiang Nong Long, Bai Hong, and Pa Sang districts, exhibited the highest recharge rate of 134.6 mm/y but covered a smaller area of 67 km2. Stable isotopic data verified that recent precipitation predominantly recharged shallow groundwater, with minimal evaporation or isotopic exchange. The basin-wide average recharge rate was 104 mm/y, reflecting the combined influence of geology, permeability, and spatial distribution. These findings provide critical insights for sustainable groundwater management in the region, particularly in the context of climate change and increasing water demand.

3D flow of ternary nanofluid over non-linear surface by using surface response methodology with thermophoretic and Brownian aspects and by considering Xue and Yamada conductivity models

3D flow of ternary nanofluid over non-linear surface by using surface response methodology with thermophoretic and Brownian aspects and by considering Xue and Yamada conductivity models

A methodology for evaluating fluid-dynamic forces on immersed bodies in 3D fluid flows with nonmatching fluid–body meshes

A methodology for evaluating fluid-dynamic forces on immersed bodies in 3D fluid flows with nonmatching fluid–body meshes

The new theorem of the steady, inviscid, compressible, guided and irrotational flows through internally foliated stream surfaces which are adapted to the geometry of Laval-nozzle casings, demonstrated on a 3D flow

The new theorem of the steady, inviscid, compressible, guided and irrotational flows through internally foliated stream surfaces which are adapted to the geometry of Laval-nozzle casings, demonstrated on a 3D flow

Possibility of modern ultrasound imaging of portal venous system.

During the past few years, there have been a number of new technical developments in the field of high-performance ultrasound diagnostics, which should help us to better assess dynamic vascular changes with ultrasound. BMUS enables us to get important anatomical variants with regard to the portal venous vessels and the hepatic veins. With color-coded duplex sonography (CCDS), and power Doppler (PD), examiners can carry out a comprehensive hemodynamic assessment of the portal venous. However, low flow settings in the vein have always been a particular challenge for CCDS, since the examiner requires special experience and artefacts often occur. In this review article, we reviewed the technical basics and diagnostic possibilities of new digital vascular ultrasound methods, 3D flow methods and contrast enhanced ultrasound (CEUS) in the assessment of portal venous flow changes.

Neural optical flow for planar and stereo PIV

Neural optical flow (NOF) offers improved accuracy and robustness over existing OF methods for particle image velocimetry (PIV). Unlike other OF techniques, which rely on discrete displacement fields, NOF parameterizes the physical velocity field using a continuous neural-implicit representation. This formulation enables efficient data assimilation and ensures consistent regularization across views for stereo PIV. The neural-implicit architecture provides significant data compression and supports a space–time formulation, facilitating the analysis of both steady and unsteady flows. NOF incorporates a differentiable, nonlinear image-warping operator that relates particle motion to intensity changes between frames. Discrepancies between the advected intensity field and observed images form the data loss, while soft constraints, such as integrated Navier–Stokes residuals, enhance accuracy and enable direct pressure inference from PIV images. Additionally, mass continuity can be imposed as a hard constraint for both 2D and 3D flows. Results from synthetic planar and stereo PIV datasets, as well as experimental planar data, demonstrate that NOF outperforms state-of-the-art wavelet-based OF, cross-correlation, and selected supervised machine learning methods. Beyond PIV, NOF could be used in conjunction with techniques like background-oriented schlieren, molecular tagging velocimetry, and other advanced measurement systems.

Direct numerical simulation of flow around two non-identical tandem cylinders: Study of secondary wake transition and flow structure

The transition of wake flow behind two non-identical tandem cylinders from a two-dimensional (2D) flow regime to a three-dimensional (3D) flow regime is investigated using direct numerical simulation. The upstream cylinder has a square cross section (b1*=b1/a=1), while the downstream cylinder has a rectangle cross section with b2*=b2/a=1,4, where b and a represent the cross-sectional length and width of the cylinders, respectively. The gap spacing between the cylinders, ranging from S*=S/a=2 to 5, is explored over a range of Reynolds numbers (Re) from 150 to 500. The critical Reynolds numbers for the onset of wake transition from a two- to a three-dimensional flow (Recr2) were determined for b2*=4 and S*=2−5, and also for b2*=1 and S*=4, e.g., Recr2 = 212.5 ± 12.5 and 162.5±12.5 at S*=4 for b2*= 4 and 1, respectively. The results show that decreasing S* delays the secondary wake transition to higher Reynolds numbers. The instantaneous flow structures identify that increasing the Reynolds number for a given b2* shifts the instability mode from mode A to mode B, and eventually to a disordered wake flow. Specifically, at Re = 300–400, the gap flow undergoes mode B, while the wake flow behind the downstream cylinder exhibits a combination of modes A and B. Additionally, a hysteresis phenomenon is observed at S*=4 and Re = 250 (b2*= 4), and also three instantaneous and four mean flow patterns were identified based on the results of this study. The impact of increasing the cylinder spanwise length from 4a to 7a was also investigated and found that its effects on most of the results are negligible.

Improved Lagrangian flow network and its application to pattern evolution and mass transport in three-dimensional cavitating flow around a hydrofoil

The complex behaviors of cavitation in three-dimensional (3D) cavitating vortical flow around a hydrofoil can be studied in detail using an improved Lagrangian method combined with a subgrid model. In addition, the interactions between cavitation and vortices are investigated from Lagrangian point of view. First, the 3D multiphase flow algorithm coupled with a Lagrangian subgrid model is developed to effectively capture multi-scale dynamics within the flow field. Then, the unique characteristics and dynamics of cloud and sheet cavitation phases are analyzed, emphasizing their distinct impact on fluid flow and vortex formation. In particular, the formation of the cavitation pattern in cloud cavitation is closely linked to the development of the primary vortex, with the shedding of the cavity being significantly influenced by the dynamics of the re-entrant flow. Moreover, mass transport channels are identified in Lagrangian flow network, which can be used to examine how the flow structures move and interact within the cavitating flow. Finally, an in-depth analysis is carried out to evaluate the impact of different parameter settings on the propagation and behavior of cavitation, particularly in the spanwise direction. The sources and implications of numerical errors that arise during the simulations are also discussed, and the insights gained from distinguishing between different cavitation patterns and studying their specific behaviors contribute significantly to the fields of fluid mechanics and marine engineering. In summary, this study aims to provide more reliable and accurate models for predicting and managing cavitation in practical applications, by improving the applicability of Lagrangian flow networks.

Hall current and MHD impacts on a 3D Maxwell nanofluid flow across a porous stretching surface

Hall current and MHD impacts on a 3D Maxwell nanofluid flow across a porous stretching surface

ICPINN: Integral conservation physics-informed neural networks based on adaptive activation functions for 3D blood flow simulations

ICPINN: Integral conservation physics-informed neural networks based on adaptive activation functions for 3D blood flow simulations

Multi-layer neural network on 3D transition metal hydrides-based ternary nanofluid flow with entropy: Application to spinning disk reactor

Multi-layer neural network on 3D transition metal hydrides-based ternary nanofluid flow with entropy: Application to spinning disk reactor

Construction of 3D MHD pressure drop correlation and flow characterization in the contraction region of a fusion blanket manifold

Construction of 3D MHD pressure drop correlation and flow characterization in the contraction region of a fusion blanket manifold

Impact of solar thermal radiation and shape factors on 3D flow of Casson tetra hybrid nanofluid

Impact of solar thermal radiation and shape factors on 3D flow of Casson tetra hybrid nanofluid

The Uncertainties of Ecosystems with the Fluvial Hydrodynamics LUO Ching-Ruey (Edward)

Fluvial ecosystems, a colorful platform of the interactions between human being and environment. The hydrologists and the geomorphologists summarize the idea of relevant factors of regional context, which including watershed hydrology, watershed geomorphology, water quality, stream and riparian ecology and stream/river hydraulics, such as water depth, width of channel, flow velocity, bed material and slope of stream/river, to transport nutrient and thermal regimes changing temporally and spatial, make the ecosystem alive. And they are obviously important of watershed management on decision support for the necessities to manage water resources in environments, fluvial ecosystem diversity, explaining watershed processes and the effects of disturbances across different regions including the human behaviors. Turbulence as a scalar quantity is a useful descriptor of turbulence in complex 3D flows characterized by non-zero vorticity. There is no general rule on when, why and which hydraulic model should be applied for eco-hydraulic studies but fundamentally the accurate topographical survey at the resolution of the scale of the processes investigated is more essential. All of them own uncertainties. Understanding the fundamental associations and relationships between hydraulic forces and floral and faunal communities, species, and their habitats, modelling them and using this information to provide management recommendations continues to be important and challenging goals for river scientists, managers, and other end users. In this paper, the characteristics of fluvial ecosystem with its variable factors will be illustrated and then the functions of fluvial ecosystem are following. Finally, the impact mechanisms resulting uncertainties on the platform are emphasized with their conceptual solving strategies.