المؤلفون: Bramasta, Rakai Aji¹ (AUTHOR), Wardana, Raka Sudira¹ (AUTHOR) raka.sw@universitaspertamina.ac.id, Sarwono² (AUTHOR)

المصدر: AIP Conference Proceedings. 2024, Vol. 3076 Issue 1, p1-10. 10p.

مصطلحات موضوعية: *HERSCHEL-Bulkley model, *HYDRAULICS

مستخلص: The Nareswari well is an onshore production well designed as a horizontal well with an inclination of 90˚. Initially, the Nareswari well was designed with a standard hole size, but to reduce drilling costs, this well will be designed to be a slim hole well. On the other hand, drilling a slim hole well has a feasibility challenge, especially if the well is designed horizontally. This study aims to analyze and design optimal hydraulics for horizontal slim hole drilling operations so that the feasibility challenges can be resolved. Data processing uses the WellPlan Landmark Software. The rheological models used in designing drilling hydraulics use the Herschel-Bulkley model. The hydraulic analysis and design focused on drilling section 4 at 6-1/8" hole size of the Nareswari well by selecting the circulation flow rate and the total nozzle bit area. The analyzed drilling hydraulic method uses Bit Hydraulics Horsepower (BHHP) which is detailed in the form of Hydraulics Horsepower per Square Inch (HSI) to determine the amount of power per unit area. The hydraulic design focuses on obtaining optimal HSI with a maximum limit of 5 hp/inch2. Based on the analysis in this study, the optimal hydraulic design was obtained for a horizontal slim hole well. In addition, the hydraulic comparison between the standard hole and slim hole wells is obtained. In this comparison, the parameters that need to be considered are obtained so that the horizontal slim hole well drilling operation can be applied efficiently. [ABSTRACT FROM AUTHOR]

المؤلفون: Donaldson, Paul J.¹ p.donaldson@auckland.ac.nz, Petrova, Rosica S.¹, Nair, Nikhil¹, Chen, Yadi¹, Schey, Kevin L.²

المصدر: Journal of Physiology. Jul2024, Vol. 602 Issue 13, p3041-3056. 16p.

مصطلحات موضوعية: *HYDRAULICS, *AQUAPORINS, *HYDROSTATIC pressure, *GEOMETRY, *OSMOSIS, *PERMEABILITY

مستخلص: The ocular lens is an important determinant of overall vision quality whose refractive and transparent properties change throughout life. The lens operates an internal microcirculation system that generates circulating fluxes of ions, water and nutrients that maintain the transparency and refractive properties of the lens. This flow of water generates a substantial hydrostatic pressure gradient which is regulated by a dual feedback system that uses the mechanosensitive channels TRPV1 and TRPV4 to sense decreases and increases, respectively, in the pressure gradient. This regulation of water flow (pressure) and hence overall lens water content, sets the two key parameters, lens geometry and the gradient of refractive index, which determine the refractive properties of the lens. Here we focus on the roles played by the aquaporin family of water channels in mediating lens water fluxes, with a specific focus on AQP5 as a regulated water channel in the lens. We show that in addition to regulating the activity of ion transporters, which generate local osmotic gradients that drive lens water flow, the TRPV1/4‐mediated dual feedback system also modulates the membrane trafficking of AQP5 in the anterior influx pathway and equatorial efflux zone of the lens. Since both lens pressure and AQP5‐mediated water permeability (PH2O${P_{{{\mathrm{H}}_{\mathrm{2}}}{\mathrm{O}}}}$) can be altered by changes in the tension applied to the lens surface via modulating ciliary muscle contraction we propose extrinsic modulation of lens water flow as a potential mechanism to alter the refractive properties of the lens to ensure light remains focused on the retina throughout life. [ABSTRACT FROM AUTHOR]

المؤلفون: Iskhakov, Arsen S.¹ (AUTHOR) aiskhak@ncsu.edu, Coppo Leite, Victor² (AUTHOR), Merzari, Elia² (AUTHOR), Dinh, Nam T.¹ (AUTHOR)

المصدر: Nuclear Science & Engineering. Jul2024, Vol. 198 Issue 7, p1426-1438. 13p.

مصطلحات موضوعية: *THERMAL hydraulics, *GRIDS (Cartography), *TURBULENT mixing, *EDDY viscosity, *MULTISCALE modeling, *GRID cells, *COMPUTATIONAL fluid dynamics

الشركة/الكيان: TEXAS A & M University

مستخلص: Traditional one-dimensional system thermal-hydraulic analysis has been widely applied in the nuclear industry for licensing purposes because of its numerical efficiency. However, such tools have inherently limited opportunities for modeling multiscale multidimensional flows in large reactor enclosures. Recent interest in three-dimensional coarse grid (CG) simulations has shown their potential in improving the predictive capability of system-level analysis. At the same time, CGs do not allow one to accurately resolve and capture turbulent mixing and stratification, whereas implemented in CG solvers relatively simple turbulence models exhibit large model form uncertainties. Therefore, there is a strong interest in further advances in CG modeling techniques. In this work, two high-to-low data-driven (DD) methodologies (and their combination) are explored to reduce grid and model-induced errors using a case study based on the Texas A&M upper plenum of a high-temperature gas-cooled reactor facility. The first approach relies on the use of a DD turbulence closure [eddy viscosity predicted by a neural network (NN)]. A novel training framework is suggested to consider the influence of grid cell size on closure. The second methodology uses a NN to predict velocity errors to improve low-fidelity results. Both methodologies and their combination have shown the potential to improve CG simulation results by using data with higher fidelity. [ABSTRACT FROM AUTHOR]

المؤلفون: Gauthey, Alice^1,2 (AUTHOR) alice.gauthey@epfl.ch, Bachofen, Christoph^1,2 (AUTHOR), Chin, Alana³ (AUTHOR), Cochard, Hervé⁴ (AUTHOR), Gisler, Jonas⁵ (AUTHOR), Mas, Eugénie^1,2 (AUTHOR), Meusburger, Katrin⁶ (AUTHOR), Peters, Richard L⁷ (AUTHOR), Schaub, Marcus⁵ (AUTHOR), Tunas, Alex^1,2,8 (AUTHOR), Zweifel, Roman⁵ (AUTHOR), Grossiord, Charlotte^1,2 (AUTHOR)

المصدر: Journal of Experimental Botany. 5/20/2024, Vol. 75 Issue 10, p3141-3152. 12p.

مصطلحات موضوعية: *SCOTS pine, *HYDRAULICS, *DROUGHTS, *HYDRAULIC conductivity, *IRRIGATION, *ACCLIMATIZATION, *ATMOSPHERIC pressure, *VAPOR pressure

مستخلص: Climate change is predicted to increase atmospheric vapor pressure deficit, exacerbating soil drought, and thus enhancing tree evaporative demand and mortality. Yet, few studies have addressed the longer-term drought acclimation strategy of trees, particularly the importance of morphological versus hydraulic plasticity. Using a long-term (20 years) irrigation experiment in a natural forest, we investigated the acclimation of Scots pine (Pinus sylvestris) morpho-anatomical traits (stomatal anatomy and crown density) and hydraulic traits (leaf water potential, vulnerability to cavitation (Ψ50), specific hydraulic conductivity (K s), and tree water deficit) to prolonged changes in soil moisture. We found that low water availability reduced twig water potential and increased tree water deficit during the growing season. Still, the trees showed limited adjustments in most branch-level hydraulic traits (Ψ50 and K s) and needle anatomy. In contrast, trees acclimated to prolonged irrigation by increasing their crown density and hence the canopy water demand. This study demonstrates that despite substantial canopy adjustments, P. sylvestris may be vulnerable to extreme droughts because of limited adjustment potential in its hydraulic system. While sparser canopies reduce water demand, such shifts take decades to occur under chronic water deficits and might not mitigate short-term extreme drought events. [ABSTRACT FROM AUTHOR]

المؤلفون: Varma, Anwesha¹ (AUTHOR), Nidhul, Kottayat¹ (AUTHOR) nidhul07@gmail.com

المصدر: Journal of Thermal Analysis & Calorimetry. May2024, Vol. 149 Issue 9, p4209-4225. 17p.

مصطلحات موضوعية: *NANOFLUIDS, *THERMAL hydraulics, *COMPUTATIONAL fluid dynamics, *TURBULENCE, *HEAT exchangers, *TURBULENT flow, *TWO-phase flow

مستخلص: A three-dimensional computational fluid dynamics (CFD) study is carried out to explore the effect of duct cross section on the thermo-hydraulic performance of various ducts. A finite volume-based scheme with an SST k-omega model and mixture model (two-phase model) was used to obtain more realistic results. A two-phase mixture model was used to consider the movement between base fluid and nanoparticles. Al2O3 nanoparticle having a volume fraction of 0.01% and 42 nm as particle size, the heat transfer and friction factor characteristic are studied for turbulent flow regime (3000 < Re < 9000) with variable thermo-physical properties. A maximum enhancement of 86% in heat transfer rate is obtained for the serpentine duct compared to the conventional circular duct at Re = 4500. Owing to a significantly lower increase in pressure drop, the elliptical duct has the highest thermo-hydraulic performance parameter of 1.54 relative to the circular duct. Further, to analyze the heat transfer quality, the entropy generation rate is studied, and it is observed that the square duct reported the highest with an increase of 60% and the elliptical duct the lowest with a reduction of 54% relative to the circular duct. This study can aid in choosing the duct geometry to enhance the heat transfer rate with nanofluid for applications such as solar-thermal, heat exchangers, etc. [ABSTRACT FROM AUTHOR]

المؤلفون: Gürsoy, Emrehan¹ (AUTHOR) emrehangursoy@gmail.com, Pazarlioğlu, Hayati Kadir² (AUTHOR) hayati-kadir.pazarlioglu@itlr.uni-stuttgart.de, Gürdal, Mehmet³ (AUTHOR) mgurdal@kastamonu.edu.tr, Gedik, Engin⁴ (AUTHOR) egedik@karabuk.edu.tr, Arslan, Kamil⁵ (AUTHOR) kamilarslan@karabuk.edu.tr, Dağdeviren, Abdullah¹ (AUTHOR) abdullahdagdeviren@karabuk.edu.tr

المصدر: International Journal of Numerical Methods for Heat & Fluid Flow. 2024, Vol. 34 Issue 5, p1969-1994. 26p.

مصطلحات موضوعية: *THERMAL hydraulics, *CONVEX geometry, *GEOMETRIC surfaces, *CONVEX surfaces, *HEAT convection, *MAGNETIC field effects, *SURFACE geometry

مستخلص: Purpose: The purpose of this study is to analyse the magnetic field effect on Fe3O4/H2O Ferrofluid flowing in a sudden expansion tube, which has specific behaviour in terms of rheology, with convex dimple fins. Because the investigation of flow separation is a prominent application in performance, the effect of magnetic field and convex dimple on the thermo-hydraulic performance of sudden expansion tube are examined, in detail. Design/methodology/approach: During the solution of the boundary conditions of the sudden expansion tube, finite volume method was used. Analyses have been conducted considering the single-phase solution, steady-state, incompressible fluid and no-slip condition of the wall under forced convection conditions. In the analyses, it has been assumed that the flow was developing thermally and has been fully developed hydrodynamically. Findings: The present study focuses on exploring the influence of the magnetic field, nanofluid concentration and convex dimple fins on the thermo-hydraulic performance of sudden expansion tube. The results indicate that the strength of the magnetic field, nanofluid concentration and convex dimple fins have a positive effect on the convective heat transfer in the system. Originality/value: The authors conducted numerical studies, determining through a literature search that no one had yet investigated enhancing heat transfer on a sudden expansion tube using combinations of magnetic fields, nanofluids and convex dimple fins. The results of the numerical analyses provide valuable information about the improvement of heat transfer and system performance in electronic device cooling and heat exchangers. [ABSTRACT FROM AUTHOR]

المؤلفون: Guo, Jing‐Jing^1,2 (AUTHOR), Gong, Xue‐Wei^1,2 (AUTHOR), Li, Xue‐Hua¹ (AUTHOR), Zhang, Chi³ (AUTHOR), Duan, Chun‐Yang³ (AUTHOR), Lohbeck, Madelon⁴ (AUTHOR), Sterck, Frank⁴ (AUTHOR), Hao, Guang‐You^1,2 (AUTHOR) haogy@iae.ac.cn

المصدر: Plant, Cell & Environment. Aug2024, Vol. 47 Issue 8, p2999-3014. 16p.

مصطلحات موضوعية: *HYDRAULICS, *SHRUBS, *RESTORATION ecology, *PLANT-water relationships, *GROWTH, *SUSTAINABILITY, *CARBON

مصطلحات جغرافية: CHINA

مستخلص: Crown removal revitalises sand‐fixing shrubs that show declining vigour with age in drought‐prone environments; however, the underlying mechanisms are poorly understood. Here, we addressed this knowledge gap by comparing the growth performance, xylem hydraulics and plant carbon economy across different plant ages (10, 21 and 33 years) and treatments (control and crown removal) using a representative sand‐fixing shrub (Caragana microphylla Lam.) in northern China. We found that growth decline with plant age was accompanied by simultaneous decreases in soil moisture, plant hydraulic efficiency and photosynthetic capacity, suggesting that these interconnected changes in plant water relations and carbon economy were responsible for this decline. Following crown removal, quick resprouting, involving remobilisation of root nonstructural carbohydrate reserves, contributed to the reconstruction of an efficient hydraulic system and improved plant carbon status, but this became less effective in older shrubs. These age‐dependent effects of carbon economy and hydraulics on plant growth vigour provide a mechanistic explanation for the age‐related decline and revitalisation of sand‐fixing shrubs. This understanding is crucial for the development of suitable management strategies for shrub plantations constructed with species having the resprouting ability and contributes to the sustainability of ecological restoration projects in water‐limited sandy lands. Summary statement: Embolism accumulation restricted carbon assimilation in aging shrubs and resulted in growth decline, while the crown‐removal treatment revitalised plants by promoting the construction of new hydraulic systems in resprouts and enhancing carbon balance through the removal of dysfunctional old stems. [ABSTRACT FROM AUTHOR]

المؤلفون: Dessers, Christophe, Archambeau, Pierre, Dewals, Benjamin, Erpicum, Sébastien, Pirotton, Michel

المصدر: EGU General Assembly 2024, 15 avril 2024 au 20 avril 2024

مصطلحات موضوعية: Hydrology, Numerical Modelling, Hydrological modelling, Hydraulics, Engineering, computing & technology, Civil engineering, Physical, chemical, mathematical & earth Sciences, Earth sciences & physical geography, Ingénierie, informatique & technologie, Ingénierie civile, Physique, chimie, mathématiques & sciences de la terre, Sciences de la terre & géographie physique

الوصف: In hydrology, a plethora of modelling approaches exist. They differ in several aspects, including the underlying hypotheses (empirical, conceptual vs. physically based) and the spatial discretisation (lumped, semi-distributed, gridded). The advent of machine learning or AI techniques further expands the spectrum of available modelling options. In this context, there is a growing scientific interest in systematically comparing existing models, understanding the reasons behind their relative performance, and applying multi-model approaches to increase the reliability of the outcomes. However, few research has been carried out so far to compare all these types of models in the same framework, namely using similar input data, pre-processing procedures, parameter optimisation algorithms and strategy, objective function, etc. WOLFHydro, developed by the HECE group at the University of Liège, offers such a framework. It addresses a flexible simulation tool organised in ‘modules’ and capable of representing any catchment, thus keeping a tuneable level of complexity and details in the description of all the physical processes at work, while remaining in the same modelling environment and starting from exactly the same input data. The software parcels out a catchment into sub-catchments or evaluation points, which are arranged in a topology network. Each module can contain a chosen type of model (physically based, conceptual, empirical) with the desired spatial representation (lumped, gridded, semi-distributed) to be assembled and facilitate the creation of hybrid models. The software also accommodates anthropogenic structures, such as dams, storage basins, or any other hydraulic structure defined by a set of operation rules customable by the user. The software currently contains a number of models developed in-house, as well as widely accepted ones (GR4H, VHM, etc). They have been validated and tested on several Belgian catchments, in particular for the 2021 extreme floods in the Vesdre and Amblève valleys. The software also features post-processing tools and a GUI interface to facilitate inspection of the results. Thanks to its versatility, WOLFHydro aims at reducing biases in model comparisons conducted in separated frameworks, improving our understanding of dominant hydrological processes, improving the evaluation of the influence model structure complexity, and carry out ensemble modelling.

الوصول الحر: https://orbi.uliege.be/handle/2268/316882Test

المؤلفون: Okagaki, Yuria¹ (AUTHOR), Hibiki, Takashi² (AUTHOR), Sibamoto, Yasuteru¹ (AUTHOR)

المصدر: International Journal of Energy Research. 4/24/2024, Vol. 2024, p1-37. 37p.

مصطلحات موضوعية: *THERMAL hydraulics, *THREE-dimensional flow, *SINGLE-phase flow, *TWO-phase flow, *LARGE eddy simulation models, *FLOW simulations, *PRESSURIZED water reactors

مستخلص: In pressurized water reactor accident scenarios, the injection of water from the emergency core cooling system (ECCS) (ECC injection) might induce a pressurized thermal shock (PTS), affecting the reactor pressure vessel (RPV) integrity. Therefore, PTS is a vital research issue in reactor safety, and its analysis is essential for evaluating the integrity of RPVs, which determines the reactor life. The PTS analysis comprises a coupled analysis between thermal–hydraulic and structural analyses. The thermal–hydraulic approach is particularly crucial, and reliable computational fluid dynamic (CFD) simulations should play a vital role in the future because predicting the temperature gradient of the RPV wall requires data on the transient temperature distribution of the downcomer (DC). Since one-dimensional codes cannot predict the complex three-dimensional flow features during ECC injection, PTS is one reactor safety issue where CFD simulation can benefit from complement evaluations with thermal–hydraulic system analysis codes. This study reviewed from the viewpoint of the turbulence models most affecting PTS analysis based on papers published since 2010 on single- and two-phase flow CFD simulation for the experiment on PTS performed in the Rossendorf coolant mixing model (ROCOM), transient two-phase flow (TOPFLOW), upper plenum test facility (UPTF), and large-scale test facility (LSTF). The results revealed that in single-phase flow CFD simulation, where knowledge and experience are sufficient, various turbulence models have been considered, and many analyses using large eddy simulation (LES) have been reported. For two-phase flow analysis of air–water conditions, interface capturing/tracking methods were used in addition to two-fluid models. The standard k – ε and shear stress transport (SST) k – ω models were still in the validated phase, and various turbulence models have yet to be fully validated. In the two-phase flow analysis of steam–water conditions, many studies have used two-fluid models and Reynolds-averaged Navier-Stoke (RANS), and NEPTUNE_CFD, in particular, has been reported to show excellent prediction performance based on years of accumulated validation. [ABSTRACT FROM AUTHOR]

المؤلفون: Jain, Piyush¹ (AUTHOR) pj248@cornell.edu, Huber, Annika E.² (AUTHOR), Rockwell, Fulton E.³ (AUTHOR), Sen, Sabyasachi¹ (AUTHOR), Holbrook, N. Michele³ (AUTHOR), Stroock, Abraham D.^2,4,5 (AUTHOR) abe.stroock@cornell.edu

المصدر: New Phytologist. Apr2024, Vol. 242 Issue 2, p453-465. 13p.

مصطلحات موضوعية: *XYLEM, *HYDRAULICS, *TOMATOES, *WATER transfer, *TISSUES, *NANOPARTICLES, *WATER use

مستخلص: Summary: The water status of the living tissue in leaves is critical in determining plant function and global exchange of water and CO2. Despite significant advances in the past two decades, persistent questions remain about the tissue‐specific origins of leaf hydraulic properties and their dependence on water status.We use a fluorescent nanoparticle reporter that provides water potential in the mesophyll apoplast adjacent to the epidermis of intact leaves to complement existing methods based on the Scholander Pressure Chamber (SPC). Working in tomato leaves, this approach provides access to the hydraulic conductance of the whole leaf, xylem, and outside‐xylem tissues.These measurements show that, as stem water potential decreases, the water potential in the mesophyll apoplast can drop below that assessed with the SPC and can fall significantly below the turgor loss point of the leaf. We find that this drop in potential, dominated by the large loss (10‐fold) of hydraulic conductance of the outside‐xylem tissue, is not however strong enough to significantly limit transpiration.These observations highlight the need to reassess models of water transfer through the outside‐xylem tissues, the potential importance of this tissue in regulating transpiration, and the power of new approaches for probing leaf hydraulics. [ABSTRACT FROM AUTHOR]