Features of the power-law fluid over cylinders in a channel via gap aspects: Galerkin finite element method (GFEM)-based study

The goal of this investigation is to carry out a comprehensive analysis of hydrodynamic forces, with particular attention being paid to the power-law fluid flow across cylinders and presence gap considerations. With the assistance of the Galerkin finite element method (GFEM), the discretization of the two-dimensional system of non-linear partial differential equations was successfully completed. The research is carried out with a significant variance of the flow behavior index n from .3 to 1.7, gap aspects Gp from 0 .0 to .3, and fixed Reynolds number Re 20. To obtain an extremely accurate solution, first, a coarse hybrid computational mesh needs to be developed, and then, more refinement must take place. The selection of the best possible case can be determined by comparing flow patterns, coefficients of drag and lift, and cylinder gaps. The shear-thickening behavior of fluids has a substantially greater influence on the drag characteristics than either the Newtonian or the shear-thinning behavior of fluids do. In addition to this, the shear-thickening action causes the upstream obstacle’s drag coefficient to increase because the gap spacing becomes more widespread

Battery charger load-following controller for over-voltage and under-voltage conditions

Battery charging systems are integral to the efficient operation and economic benefit of various applications, from electric vehicles to renewable energy storage. However, maintaining battery charging according to specifications during voltage variations, including short or prolonged under-voltage and over-voltage conditions, presents a significant challenge. These voltage variations can impact the thermal safety and charging time of batteries, potentially affecting their overall performance and life span. In order to address these challenges, this paper proposes a smart charging control method designed to control both the battery charging voltage and load voltages. This method is equipped to handle utility interruptions by using regulated AC–DC converters, while an automatic interconnected DC regulator controls the battery state of charge (SOC) and load supply. This dual control mechanism ensures efficient performance under various conditions. Extensive simulations validate the effectiveness of the proposed method, demonstrating its ability to maintain a constant voltage supplied to the load and ensures the thermal safety of the system during under- and over-voltage conditions. Additionally, an analysis of the thermal effect of the charger under these voltage conditions provides valuable insights into the thermal performance of the system, which is a critical aspect of battery charging systems. The proposed charging control method offers a comprehensive solution for efficient battery charging under various voltage conditions, thus contributing to the better performance, thermal safety, and longevity of batteries

Finite Element Analysis of the Dynamics of Power-Law Fluid around an Obstacle in a Channel

Control of uid forces is an emerging area of research with numerous engineering applications. ­e uneven wake behind an obstacle causes undesirable structural oscillations, which can lead to fatigue or structural failure. Controlling the wake phenomena could directly bene t a wide range of engineering applications, including skyscrapers, naval risers, bridges, columns, and a few sections of airplanes. ­is study is concerned with the time dependent simulations in a channel in presence of an obstacle aiming to compute uid forces. ­e underlying mathematical model is based on nonstationary Navier–Stokes equations coupled with the constitutive relations of power law uids. Because the representative equations are complex, an e ective computing strategy based on the nite element approach is used. To achieve higher accuracy, a hybrid computational grid at a very ne level is used. ­e P2 − P1 elements based on the shape functions of the second and rst-order polynomials were used to approximate the solution. ­e discrete nonlinear system arising from this discretization is linearized by Newton’s method and then solved through a direct linear solver PARADISO. ­e code validation study is also performed for Newtonian uids as a special case, and then the study is extended to compute drag and lift forces for other cases of viscosity as described by the power law index. When looking at the phase plot, it can be seen that for the Newtonian case n 1, there is only one closed orbit after the steady state is reached, whereas for n 0.5, there are multiple periodic orbits. Moreover, the e ects of shear rate on the drag-lift phase plot are also discussed.Scopu

Numerical Computation for Modified Cross Model Fluid Flow Around the Circular Cylinder with Symmetric Trapezoidal Cavities

This manuscript explores the flow features of the Modified Cross Model in a channel with symmetric trapezoidal cavities in the presence of a circular obstacle. The non-dimensional governing equations and model for different parameters are evaluated via a Galerkin Finite Element Method The system of non-linear algebraic equations is computed by adopting the Newton method. A space involving the quadratic polynomials (P2) has been selected to compute for the velocity profile while the pressure profile is approximated by a linear (P1) finite element space of functions. Simulations are performed for a wide range of physical parameters such as modified parameter (from 0.0 to 0.5), power-law index (from 0.5 to 1.5), relaxation parameter (from 1 to 3), and Reynolds number (from 10 to 40). For the case of a modified parameter (b) and relaxation parameter (λ), it is observed that the drag coefficient (CD) shows an increasing trend while the lift coefficient (CL) is changing sign at lower values of (λ), and then becomes positive at λ=3

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

Background Disorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021. Methods We estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined. Findings Globally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer. Interpretation As the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed. Funding Bill & Melinda Gates Foundation

Flow of the Bingham-Papanastasiou Regularized Material in a Channel in the Presence of Obstacles: Correlation between Hydrodynamic Forces and Spacing of Obstacles

The numerical modeling and simulation for the stationary Bingham fluid flow around two confined circular cylinders with various gap ratios are studied. The singularity in the model’s apparent viscosity is dealt by Papanastasiou’s regularization. The model equations are discretized by adopting the methodology based on finite element method (FEM) by choosing a mixed higher order LBB-stable P2−P1 finite element pair. The direct solver PARADISO has been utilized to solve the linearized system of equations. Hydrodynamic forces represented by drag and lift coefficients are computed, and a correlation coefficient is calculated for the gap ratios 0.1≤Gp≤0.3 and for several values of the Bingham number 0≤Bn≤50. Line graphs for horizontal and vertical velocities are drawn. Moreover, velocity and pressure profiles are plotted for pertinent values of the parameters. Plug and shear zones are revealed via velocity snapshots in the domain. Pressure is nonlinear in the vicinity of the obstacles and becomes linear downstream in the cylinders as expected in channel flows

Darcy-Forchheimer flow of maxwell nanofluid flow over a porous stretching sheet with Arrhenius activation energy and nield boundary conditions

This work investigates the effect of heat transfer and mass transfer on the convective Darcy-Forchheimer flow of a Maxwell nanofluid through a linear porous stretched sheet. In addition, the impacts of chemical reaction, thermal conductivity, and thermophoresis are investigated. The analysis of heat and mass transfer in the presence of nanoparticles in a Maxwell fluid under convective and nield conditions is examined. To convert the governing PDEs of velocity, temperature and nano concentration with activation energy into a couple of nonlinear ODEs we apply the appropriate similarity variables. Shooting method is applied to solve the set of highly nonlinear ordinarily differential equations numerically and obtained numerical results are associated with those gained by the help of MATLAB bvp4c solver and Mathematica ND-solve built in command. The influence of prominent parameters of interest like chemical effusion, Prandtl number, Biot number, radiative heat flux Brownian motion, Lewis number, thermophoresis parameter, magnetic parameter, Reynolds number, thermophoresis parameter, on, non-dimension velocity, heat and nano concentration distribution has been deliberated and heat transfer features is also encompassed. The numerical values obtained for defined profiles are presented through graphs and tables

Computational Analysis of Fluid Forces on an Obstacle in a Channel Driven Cavity: Viscoplastic Material Based Characteristics

In the current work, an investigation has been carried out for the Bingham fluid flow in a channel-driven cavity with a square obstacle installed near the inlet. A square cavity is placed in a channel to accomplish the desired results. The flow has been induced using a fully developed parabolic velocity at the inlet and Neumann condition at the outlet, with zero no-slip conditions given to the other boundaries. Three computational grids, C1, C2, and C3, are created by altering the position of an obstacle of square shape in the channel. Fundamental conservation and rheological law for viscoplastic Bingham fluids are enforced in mathematical modeling. Due to the complexity of the representative equations, an effective computing strategy based on the finite element approach is used. At an extra-fine level, a hybrid computational grid is created; a very refined level is used to obtain results with higher accuracy. The solution has been approximated using P2 − P1 elements based on the shape functions of the second and first-order polynomial polynomials. The parametric variables are ornamented against graphical trends. In addition, velocity, pressure plots, and line graphs have been provided for a better physical understanding of the situation Furthermore, the hydrodynamic benchmark quantities such as pressure drop, drag, and lift coefficients are assessed in a tabular manner around the external surface of the obstacle. The research predicts the effects of Bingham number (Bn) on the drag and lift coefficients on all three grids C1, C2, and C3, showing that the drag has lower values on the obstacle in the C2 grid compared with C1 and C3 for all values of Bn. Plug zone dominates in the channel downstream of the obstacle with augmentation in Bn, limiting the shear zone in the vicinity of the obstacle

Temporal features of thermal flows over a rotating cylinder in a channel: Multigrid based simulations

The purpose of this study is to simulate thermal flows via quasi-Newtonian modeling by employing Finite Element Methods (FEM), as well as Newton Multigrid Solvers (NMS). A heated rotating cylinder is exposed to an inflowing fluid stream in a channel to facilitate the thermal energy transfer in the fluid. The NMS may be more easily parallelized as a result of an excessive number of degrees of freedom. The discretization of a dimensionless system of partial differential equations that are to be solved over an extensive computational domain is accomplished by using the higher-order stable finite element pair. Temporal discretization is performed using a 2nd order Crank-Nicolson scheme. By applying the Newton method, the discretized nonlinear system of algebraic equations is transformed into a linear form. To compute the linearized subproblems that arise from each nonlinear sweep, a geometric multigrid approach has been put in place. The whole framework has been implemented in an open-source finite element software Featflow. It has been deduced that in a clockwise rotation of the cylinder, more fluid will move from above the cylinder, and when it is rotated in an anticlockwise direction, more fluid will move from bottom side of the cylinder. In addition to this, there is a correlation between an increase in the rotational parameter ω and a reduction in both the lift coefficient CL and drag coefficient CD. The benchmark values of CD and CL fits very well with the available data for certain special cases of this study