Analysis Of Energy Fluxes Research Articles

Internal Tides Reverse Tidal Currents Around Southern Taiwan

AbstractWe present a highly unusual case in southern Taiwan where internal tides (ITs) completely reverse the barotropic currents. A 3D baroclinic model is first validated and confirms the unexpected tidal current in that area. A series of sensitivity simulations are then used to progressively reveal the exact cause. Contrary to popular belief, a large canyon in that area is not responsible for the flow reversal. Results from using a relaxation technique in the model together with an energy flux analysis indicate that the energy of the large ITs emanated from the Luzon Strait is converted to the barotropic energy near the steep slope, which generates a local circulation and reverses the tidal flow there.

The coupling of carbon and energy fluxes reveals anaerobiosis in an aerobic soil incubation with a Bacillota-dominated community

Soil microorganisms rely on coupled fluxes of carbon and energy to fuel their maintenance, to switch from dormancy to activity and to grow under dynamically changing conditions in microhabitats. To identify the principles underlying this coupling, we measured heat and CO2 release from soil after glucose addition along with estimates of microbial biomass and community composition. The results revealed bi-directional deviations of the ratio of heat to CO2 release (Calorespirometric Ratio, CR) that are inconsistent with theoretical predictions for aerobic respiration, which is commonly assumed to be the major metabolic pathway in incubation experiments. Moreover, the microbial community was dominated by members of the Bacillota, whose relative abundance increased from 4 percent to 65 percent in 18 h. To interpret these findings, we developed a dynamic model of carbon and energy fluxes during the microbial growth on glucose. The model simulates aerobic respiration as well as anaerobic fermentation pathways to lactate, acetate and propionate depending on the time-varying availability of O2. Simulations captured the observed temporal CR pattern and suggested a gradual depletion of O2 and a shift to anaerobic pathways as the main driver. This interpretation is consistent with the dominance of Bacillota, many members of which are well adapted to anaerobic conditions. Our results highlight the potential of the joint analysis of matter and energy fluxes in combined experimental and modeling approaches and indicate the presence of facultative anaerobiosis under common experimental conditions, which could confer a competitive advantage to certain microbial taxa during growth on labile substrate.

Investigation of the effect of curvature on the local mass flux of evaporating droplets using a phase field method

Droplet evaporation, a fundamental process with wide-ranging applications, involves complex physical mechanisms that significantly influence mass transfer rates and droplet lifetimes. Despite its significance, the influence of droplet deformation induced by capillary forces on local saturation conditions and its subsequent impact on phase change have received limited attention. This study delves into the impact of capillary-induced droplet deformation on local saturation conditions and its subsequent effect on phase change within a quiescent vapor environment. Contrary to most analytical and numerical studies that impose temperature and heat flux conditions at the vapor–liquid interface, our investigation employs direct numerical simulations based on the thermal Navier–Stokes–Korteweg model, capturing the dynamics of the droplet and its interface without relying on ad-hoc interface conditions. Our findings demonstrate that droplet deformation induces free oscillatory motion, which, although not significantly altering droplet lifetime due to viscous damping, leads to non-uniform mass fluxes along the droplet interface. We observe that areas of higher curvature are associated with increased local pressure and reduced temperatures, a discrepancy primarily attributed to evaporative cooling. This effect is further elucidated through an analysis of pressure and energy fluxes, revealing that regions of high curvature experience significant heat consumption, driving evaporative cooling and creating temperature gradients along the interface. Conversely, areas with negative curvature exhibit a reverse trend, indicating the complex interplay of capillarity, deformation, and phase change in droplet evaporation. Our results highlight the intricate relationship between droplet deformation, local pressure, mass flux, and temperature, underscoring the necessity for improved modeling of these factors in future studies on droplet evaporation dynamics.

A Comparative Analysis of Intensity and Energy Flux in the Focus of the High-Numeric-Aperture Conventional and Spiral Zone Plates

A Comparative Analysis of Intensity and Energy Flux in the Focus of the High-Numeric-Aperture Conventional and Spiral Zone Plates

Spatial–temporal analysis of magnetohydrodynamics flow and energy flux of power-law nanofluid in a confined domain

Energy flux analysis of power-law fluid is a novel contribution to recent developments in computational fluid dynamics. The study of the unsteady two-dimensional flow with double diffusive effect inside a complex enclosure exhibits great potential in optimizing the heat transfer rate due to the wavy nature of the side walls. The enclosure is confined with the flow circulation due to the thermal and solutal gradients acting along the left and right wavy walls. The computational time and accuracy in results are estimated and compared by implementing the finite volume method and element-free Galerkin technique. The results are obtained in terms of streamlines, isotherms, isoconcentrations, average Nusselt number, Sherwood number, and total entropy generation due to the effect of conventional parameters, namely, power-law index, Rayleigh number, buoyancy ratio parameter, thermophoresis parameter, Brownian motion parameter, and Lewis number with a fixed Prandtl number throughout the computation. The optimized double-diffusive natural convection analysis is based on entropy generation and a calculated Bejan number. The novelty of this paper lies in the implementation of a mesh-free approach, which may be useful for the further analysis of elliptical/semi-elliptical structures.

Energy transmission pathways of equatorial waves within the Maritime Continent: a view with the wave energy flux

Detailed pathway of wave energy exchange between the Pacific and Indian Oceans through the Indonesian archipelago for a wide range of wave frequency is investigated using a reduced gravity model with realistic coastline. The wave energy flux analysis that can be applicable for all latitudes in a linear shallow water system is adopted. The energy fluxes diagnosed from the model outputs for the incoming Rossby waves from the Pacific clearly indicate two major energy pathways to the Indian Ocean: one turning southward in the Halmahera Sea and reaches the Indian Ocean via the Banda Sea and the Timor Passage, and the other passing through the Makassar and Lombok Straits. The former route, however, is shifted to the western side of the island chain within the Banda Sea due to energy trapping around the island chain. It is also found that strong energy dissipation occurs along the northern coast of New Guinea when the incoming wave period is shorter than 1.5 years. In the case of the Kelvin waves from the Indian Ocean, it is found that the major energy pathway is through the Lombok and Makassar Straits to the Pacific Ocean. However, there appears another pathway along the eastern side of the Sulawesi Island in the Banda Sea to exit through the Molucca Sea only when the wave period is shorter than about one month. This secondary pathway makes it easier for the wave energy from the Indian Ocean to reach the western Pacific Ocean for the short-period waves.

Platelet glycogenolysis is important for energy production and function

Although the presence of glycogen in platelets was established in the 1960s, its importance to specific functions (i.e., activation, secretion, aggregation, and clot contraction) remains unclear. Patients with glycogen storage disease often present with increased bleeding and glycogen phosphorylase (GP) inhibitors, when used as treatments for diabetes, induce bleeding in preclinical studies suggesting some role for this form of glucose in hemostasis. In the present work, we examined how glycogen mobilization affects platelet function using GP inhibitors (CP316819 and CP91149) and a battery of ex vivo assays. Blocking GP activity increased glycogen levels in resting and thrombin-activated platelets and inhibited platelet secretion and clot contraction, with minimal effects on aggregation. Seahorse energy flux analysis and metabolite supplementation experiments suggested that glycogen is an important metabolic fuel whose role is affected by platelet activation and the availability of external glucose and other metabolic fuels. Our data shed light on the bleeding diathesis in glycogen storage disease patients and offer insights into the potential effects of hyperglycemia on platelets.

High energy vibrational excitations of nitromethane in liquid water.

The pathways and timescales of vibrational energy flow in nitromethane are investigated in both gas and condensed phases using classical molecular mechanics, with a particular focus on relaxation in liquid water. We monitor the flow of excess energy deposited in vibrational modes of nitromethane into the surrounding solvent. A marked energy flux anisotropy is found when nitromethane is immersed in liquid water, with a preferential flow to those water molecules in contact to the nitro group. The factors that permit such anisotropic energy relaxation are discussed, along with the potential implications on the molecule's non-equilibrium dynamics. In addition, the energy flux analysis allows us to identify the solvent motions responsible for the uptake of solute energy, confirming the crucial role of water librations. Finally, we also show that no anisotropic vibrational energy relaxation occurs when nitromethane is surrounded by argon gas.

Regional tropical rainfall shifts under global warming: an energetic perspective

Future climate simulations feature pronounced spatial shifts in the structure of tropical rainfall. We apply a novel atmospheric energy flux analysis to diagnose late 21st century tropical rainfall shifts in a large ensemble of simulations of 21st century climate. The method reconstructs 2D spatial changes in rainfall based on horizontal shifts in the lines of zero meridional and zonal divergent energy flux, called the energy flux equator (EFE) and energy flux prime meridian (EFPM), respectively. Two main sources of future atmospheric energy flux changes, and hence rainfall shifts, are identified by the analysis: the high-latitude North Atlantic due to a weakened Atlantic Meridional Overturning Circulation that shifts tropical rainfall southwards over the greater Tropical Atlantic sector and eastern Pacific; and the eastern tropical Pacific due to a permanent El-Niño-like response that produces zonal shifts over the Maritime Continent and South America. To first order, the shifts in the EFE and EFPM mirror gross distributional changes in tropical precipitation, with a southward shift in rainfall over the tropical Atlantic, West Africa, and eastern tropical Pacific and an eastward shift over the Maritime Continent and western Pacific. When used to reconstruct future rainfall shifts in the tropical Atlantic and Sahel, the method reasonably represents the simulated meridional structure of rainfall shifts but does not do so for the zonal structures.

Acoustic energy flux analysis of the bifurcated waveguide by varying outlet boundaries

This communication is devoted to the analysis of the energy flux of a two-dimensional waveguide with planar and non-planar surfaces. The main goal is to analyze the effects of reflected and transmitted energy fluxes of the bifurcated waveguide by varying the different types of outlet boundaries. The upper and lower boundaries of the inlet are taken as flexural in nature, whilst the outlet of the duct is varied by soft, rigid and impedance boundary conditions. The benchmark Mode-Matching (MM) technique is applied to solve the underlying boundary value problem (BVP). The system is excited with two types of incident forcing: fluid-borne incident and structure-borne incident. For a flexible inlet bounded by a membrane, the obtained eigenfunctions are linearly dependent and non-orthogonal in character. For sake of this, generalized orthogonality relations (OR) are developed. Additionally, the application of generalized OR led to the appearance of some dependent sums that are tackled using the fixed membrane edge conditions. The application of edge conditions led to the unique solution of the BVP. In the end, the expressions of reflected and transmitted energy fluxes are obtained and analyzed graphically against frequencies for different structural properties of the waveguide. Furthermore, it is shown that the conserved energy flux is valid, and reconstructed matching conditions are found in good accord.

Evaluation and spatio-temporal analysis of surface energy flux in permafrost regions over the Qinghai-Tibet Plateau and Arctic using CMIP6 models

ABSTRACT The surface energy budget over the Qinghai-Tibet Plateau (QTP) and the Arctic significantly influences the climate system with global consequences. The performances of 30 selected Coupled Model Intercomparison Project Phase 6 (CMIP6) models were evaluated based on six sites in the QTP and Arctic. The simulation results for latent heat flux (LE) were more accurate in the QTP, where the correlation coefficient and root mean square error (RMSE) were 0.9 and 30 W m−2, respectively. The results for sensible heat flux (H) were more accurate in the Arctic, the correlation coefficient and RMSE were 0.8 and 24 W m−2, respectively. Furthermore, the multiple models mean results revealed that the surface energy flux had seasonal variation and regional differences over the QTP and the Arctic. In the QTP, H was the lowest in winter, increased in spring, and reached the maximum in summer. However, the transitional changes in spring and autumn were not apparent in the Arctic, mainly due to seasonal net radiation difference between the two places. LE was affected by precipitation and surface soil moisture content. This work is important for understanding land-atmosphere interactions and useful for improving the accuracy of land surface models simulations.

The effect of afforestation on moist heat stress in Loess Plateau, China

Study regionLoess Plateau (LP), China Study focusThis study aimed to research whether and to what degree afforestation contributes to the variations in moist heat stress in the study area. Here, wet bulb, temperature (Tw) was used to quantify the moist heat stress. Subsequently, The Weather Research and Forecasting model (WRF) is applied to simulate the modulation of climate change related to afforestation during 2001–2015. Based on the analysis of energy fluxes, we identified the biogeophysical mechanism of afforestation impact on moist heat stress. New hydrological insights for the regionSince the operation of the “Grain-to-Green” program, LP has experienced widespread afforestation which perturbs energy and water fluxes, affecting regional climate regimes. The forest expansion increases relative humidity but cools the regional temperature. As a significant combined climate factor, the average moist heat stress decreases with the magnitude of − 0.1∼− 0.3 °C in central LP. While the decrease rate of Tw is slower than near-surface temperature. It is worth noting that, an increased signal occurs in the maximum Tw (almost 0.2 °C in eastern and northeastern LP), which might expose humans to the risk of moist heat stress. By the mechanistic analysis, the research shows that the near-surface temperature and sensible heat flux are dominant driving factors for the change of Tw. Furthermore, the subsidence of the planetary boundary layer enhances moist heat stress. Overall, afforestation’s effects on land surface-atmosphere interaction are non-negligible and the moist heat stress should be accounted for in climate change adaptation strategies.

Energy flux analysis for quantification of vibratory pile driving efficiency

In this paper, the energy flux in a pile modeled as an elastic shell, is studied theoretically and experimentally. Based on this analysis, a new procedure is proposed to quantify the pile installation efficiency. This procedure is of importance for vibratory installation of the foundations of offshore wind turbines and it is believed to be the first procedure that relies directly on the energy propagating down the pile rather than the energy supplied by the vibratory shaker. The proposed approach is tested on piles installed by two distinct vibratory techniques, i.e. the axial vibratory driving and the recently developed Gentle Driving of Pile (GDP) method. The field data obtained during an experimental campaign were analyzed with the proposed energy flux approach. The cumulative energy flux in the pile normalized by the energy input of the shaker is found to be the best measure for quantification of the installation efficiency. Correspondingly, the main proposition of this paper is that the installation efficiency will be maximized provided that the normalized cumulative energy flux is at its maximum.

Climate Controls on the Interseasonal and Interannual Variability of the Surface Mass and Energy Balances of a Tropical Glacier (Zongo Glacier, Bolivia, 16°S): New Insights From the Multi‐Year Application of a Distributed Energy Balance Model

AbstractThe application of a distributed energy balance model over nine years at an hourly time step to a 20 × 20 m grid cell over Glacier Zongo (Bolivia, 16°S) enabled assessment of the climate factors that control the interseasonal and interannual variability of its surface mass balance. The model was validated by comparing the measured and simulated discharge at the outlet, albedo at the Automatic Weather Station, surface state and annual mass balance both glacier‐wide and as a function of altitude. Analysis of the mean monthly energy fluxes highlighted the importance of the meteorological conditions over October and November on the variability of the annual surface mass balance. Two sensitivity analyses are presented, one of the distribution of precipitation over time which maintains a physical coherence between the different meteorological variables and one of the impact of prolonged periods of intense cloud radiative forcing on the surface mass balance. The distribution of precipitation events over time and their associated amounts are the main drivers of the interannual variability of the surface mass balance via an albedo feedback effect. Additionally, prolonged periods of negative cloud radiative forcing, specifically over the month of November, notably reduce the melt rate.

Methods for the Comprehensive in vivo Analysis of Energy Flux, Fluid Homeostasis, Blood Pressure, and Ventilatory Function in Rodents.

Cardiovascular disease represents the leading cause of death in the United States, and metabolic diseases such as obesity represent the primary impediment to improving cardiovascular health. Rodent (mouse and rat) models are widely used to model cardiometabolic disease, and as a result, there is increasing interest in the development of accurate and precise methodologies with sufficiently high resolution to dissect mechanisms controlling cardiometabolic physiology in these small organisms. Further, there is great utility in the development of centralized core facilities furnished with high-throughput equipment configurations and staffed with professional content experts to guide investigators and ensure the rigor and reproducibility of experimental endeavors. Here, we outline the array of specialized equipment and approaches that are employed within the Comprehensive Rodent Metabolic Phenotyping Core (CRMPC) and our collaborating laboratories within the Departments of Physiology, Pediatrics, Microbiology & Immunology, and Biomedical Engineering at the Medical College of Wisconsin (MCW), for the detailed mechanistic dissection of cardiometabolic function in mice and rats. We highlight selected methods for the analysis of body composition and fluid compartmentalization, electrolyte accumulation and flux, energy accumulation and flux, physical activity, ingestive behaviors, ventilatory function, blood pressure, heart rate, autonomic function, and assessment and manipulation of the gut microbiota. Further, we include discussion of the advantages and disadvantages of these approaches for their use with rodent models, and considerations for experimental designs using these methods.

Ultrafast Rotational and Translational Energy Relaxation in Neat Liquids.

The excess energy flow pathways during rotational and translational relaxation induced by rotational or translational excitation of a single molecule of and within each of four different neat liquids (H2O, MeOH, CCl4, and CH4) are studied using classical molecular dynamics simulations and energy flux analysis. For all four liquids, the relaxation processes for both types of excitation are ultrafast, but the energy flow is significantly faster for the polar, hydrogen-bonded (H-bonded) liquids H2O and MeOH. Whereas the majority of the initial excess energy is transferred into hindered rotations (librations) for rotational excitation in the H-bonded liquids, an almost equal efficiency for transfer to translational and rotational motions is observed in the nonpolar, non-H-bonded liquids CCl4 and CH4. For translational excitation, transfer to translational motions dominates for all liquids. In general, the energy flows are quite local; i.e., more than 70% of the energy flows directly to the first solvent shell molecules, reaching almost 100% for CCl4 and CH4. Finally, the determined validity of linear response theory for these nonequilibrium relaxation processes is quite solvent-dependent, with the deviation from linear response most marked for rotational excitation and for the nonpolar liquids.

Analysis of Surface Weather Parameters and Energy Fluxes Over the Indian Antarctic Stations: Maitri and Bharati

Analysis of Surface Weather Parameters and Energy Fluxes Over the Indian Antarctic Stations: Maitri and Bharati

Theoretical framework for energy flux analysis of channels under drag control

A new framework analyzes energy flux in turbulent channels under various controls, enabling estimations of drag reduction and net power saving, and also suggesting a perspective of composite control for future exploration.

Energy Imbalance and Evapotranspiration Hysteresis Under an Advective Environment: Evidence From Lysimeter, Eddy Covariance, and Energy Balance Modeling

AbstractSurface energy imbalance problems have been underexplored especially under advective environments. Here, we present a novel analysis of surface energy fluxes from three distinct approaches—weighing lysimeter, eddy covariance (EC), and surface energy balance modeling for the 2014 sorghum and 2016 corn crop seasons in Bushland, Texas. Our results suggest that energy imbalance problems in the EC system were evidently associated with two opposite evapotranspiration (ET) hysteresis patterns with respect to net radiation and water vapor pressure deficit (VPD). The lysimeter ET had the smallest ET hysteresis while the eddy covariance ET results indicated the strongest hysteresis with respect to net radiation. Conversely, the lysimeter ET hysteresis related to water VPD was stronger than that of the eddy covariance method. This study provides understanding of ET hysteresis patterns, energy imbalance, and advective conditions associated with turbulent flux dynamics for both diel and crop growing seasonal timescales in Bushland, Texas.

The middle to late Eocene greenhouse climate modelled using the CESM 1.0.5

Abstract. The early and late Eocene have both been the subject of many modelling studies, but few have focused on the middle Eocene. The latter still holds many challenges for climate modellers but is also key to understanding the events leading towards the conditions needed for Antarctic glaciation at the Eocene–Oligocene transition. Here, we present the results of CMIP5-like coupled climate simulations using the Community Earth System Model (CESM) version 1. Using a new detailed 38 Ma geography reconstruction and higher model resolution compared to most previous modelling studies and sufficiently long equilibration times, these simulations will help to further understand the middle to late Eocene climate. At realistic levels of atmospheric greenhouse gases, the model is able to show overall good agreement with proxy records and capture the important aspects of a warm greenhouse climate during the Eocene. With a quadrupling of pre-industrial concentrations of both CO2 and CH4 (i.e. 1120 ppm and ∼2700 ppb, respectively, or 4 × PIC; pre-industrial carbon), sea surface temperatures correspond well to the available late middle Eocene (42–38 Ma; ∼ Bartonian) proxies. Being generally cooler, the simulated climate under 2 × PIC forcing is a good analogue for that of the late Eocene (38–34 Ma; ∼ Priabonian). Terrestrial temperature proxies, although their geographical coverage is sparse, also indicate that the results presented here are in agreement with the available information. Our simulated middle to late Eocene climate has a reduced Equator-to-pole temperature gradient and a more symmetric meridional heat distribution compared to the pre-industrial reference. The collective effects of geography, vegetation, and ice account for a global average 5–7 ∘C difference between pre-industrial and 38 Ma Eocene boundary conditions, with important contributions from cloud and water vapour feedbacks. This helps to explain Eocene warmth in general, without the need for greenhouse gas levels much higher than indicated by proxy estimates (i.e. ∼500–1200 ppm CO2) or low-latitude regions becoming unreasonably warm. High-latitude warmth supports the idea of mostly ice-free polar regions, even at 2 × PIC, with Antarctica experiencing particularly warm summers. An overall wet climate is seen in the simulated Eocene climate, which has a strongly monsoonal character. Equilibrium climate sensitivity is reduced (0.62 ∘C W−1 m2; 3.21 ∘C warming between 38 Ma 2 × PIC and 4 × PIC) compared to that of the present-day climate (0.80 ∘C W−1 m2; 3.17 ∘C per CO2 doubling). While the actual warming is similar, we see mainly a higher radiative forcing from the second PIC doubling. A more detailed analysis of energy fluxes shows that the regional radiative balance is mainly responsible for sustaining a low meridional temperature gradient in the Eocene climate, as well as the polar amplification seen towards even warmer conditions. These model results may be useful to reconsider the drivers of Eocene warmth and the Eocene–Oligocene transition (EOT) but can also be a base for more detailed comparisons to future proxy estimates.