Velocity Profile Distribution Research Articles

Thermal and Computational Analysis of MHD Dissipative Flow of Eyring-Powell Fluid: Non-Similar Approach via Overlapping Grid-Based Spectral Collocation Scheme

The aim of the present study is to numerically investigate the non-similar flow and heat transfer in a dissipative Eyring-Powell fluid (EPF) over a stretching surface. A constant magnetic field is applied perpendicular to the stretched surface to explore the impact of the Lorentz force. Both viscous and magnetic dissipation are considered to comprehensively examine their effects on heat transfer. The problem in hand does not admit self-similar solutions as the non-Newtonian fluid parameter varies with the spatial variable along the stream-wise direction. Consequently, the set of nonlinear partial differential equations, modeling the flow problem is nondimensionalized primarily by employing a pseudo-similarity variable and stream-wise coordinate. The non-dimensional set of nonlinear partial differential equations is solved by a newly developed and efficient “overlapping multi-domain bivariate spectral local linearization method (OMD-BSLLM)”. The current study includes residual error analysis and convergence tests to demonstrate the accuracy of the numerical method applied to the current mathematical model. Graphs show fluid flow and heat transfer results for different flow parameters, while tables display skin friction and Nusselt number values. The results indicate that the non-Newtonian fluid parameter enhances both the velocity profile and temperature distribution. The fluid decelerates with increasing the dimensionless stream wise coordinate and Hartmann number. Viscous dissipation and dimensionless stream-wise coordinate enhances the temperature profile.

The Influence of Non-Pressure Pipes Filled to Different Degrees on the Hydraulic Characteristics of Channel–Pipe Combined Irrigation Systems

Modern irrigation areas often use a combination of channels and pipes for irrigation. Due to changes in terrain, inflow, and pipe diameter, pipelines are often prone to experiencing a state of no pressure. This lack of pressure affects not only the velocity distribution and water surface profile of the main channel but also the velocity distribution and flow distribution of the pipeline. Therefore, in this study, we employed a combination of physical model experiments and theoretical analysis to study the influence of non-pressure pipelines on the hydraulic characteristics of channel–pipe combined irrigation systems filled to different degrees. Through this, the variation laws of the flow velocity distribution, turbulence intensity, water surface, diversion width, and diversion ratio under different filling degrees were obtained. The non-pressure pipeline flow velocity expression was obtained through dimensional analysis, and the calculation formula for the non-pressure pipeline flow velocity coefficient was fitted using linear regression analysis. The relative error between the calculated value and the measured value did not exceed 8.81%. The research results presented in this article can provide technical support for the design and maintenance of channel–pipe combined irrigation systems.

Calendering of non-isothermal viscoelastic sheets of finite thickness: A theoretical study

Abstract In this article, the sheeting of pseudoplastic material under non-isothermal conditions has been studied. It is an excellent forecasting instrument for sheeting, where the thickness of the sheet is relatively thin in relation to the roll size, according to theoretical study based on the lubrication theory. At the calendering process, the detachment point is determined by taking the material parameter’s impact into account. The governing equations are derived for the constitutive equation of the Carreau fluid with momentum and energy equations. Suitable non-dimensional parameters are used to develop the non-linear partial differential expressions into ordinary differential systems. The maximum pressure, roll separating force, normal stress effect, and power delivered to the fluid by rolls are among the engineering-relevant quantities that are determined. Moreover, a graphic analysis is conducted to examine the impact of different material parameters on the temperature profile, pressure gradient, velocity profile, and pressure distribution. The results specific mechanism is explained in depth.

Analysis of plasma wakefield generation by a Laguerre-Gaussian laser beam in laser-plasma accelerators with external injection

This study presents a comprehensive modeling of wakefield generation through external injection utilizing a Laguerre–Gaussian (LG) laser beam in a bubble/blowout regime. The wakefield dynamics are simulated in two dimensions using the particle-in-cell (2D-PIC) method via Wake-T tool, aiming to investigate the underlying mechanisms and characteristics of this process. The simulation results provide insights into the behavior of electrons within the wakefield, their acceleration, phase spaces of the electron beam, velocity distribution, and longitudinal and transversal profiles of the laser electric field in the plasma. The presented model serves as a valuable tool for further investigations into wakefield generation with external injection using LG laser beams, facilitating advancements in this field of study.

An implication of entropy generation in Maxwell fluid containing engine oil based ternary hybrid nanofluid over a riga plate

ABSTRACT Nanoparticles enhance the heat transmission by recovering energy that was dissipated due to increased thermal conductivity. Engine oil, commonly known as a lubricant, facilitates the movement of energy between various substances. The purpose of this analysis is to investigate the impact of the Maxwell fluid and entropy generation on the movement of ternary hybrid nanoparticles as they flow past a Riga plate under convective boundary conditions. The ternary nanoparticles AA 7072 , AA 7075 , and CoF e 2 O 4 are combined with engine oil ( EO ) as the primary liquid. The heat transfer analysis involves the examination of heat sink/source and thermal radiation. The use of a similarity transformation is employed to convert partial differential equations (PDEs) into a dimensionless form. The altered equation is subsequently solved with the homotopy analysis method (HAM), a robust analytical technique. The current analysis is marked by convergence, which denotes the answer. The impact of flow properties, such as the Maxwell parameter, modified Hartmann number, thermal radiation, and Biot number, on the velocity distribution and temperature profile. Higher values of the Maxwell fluid parameter have been shown to result in an increase in the velocity curve. The skin friction and heat transmission variances are elucidated through the utilization of tables and figures. Moreover, the findings suggest that the thermal layer of the tri hybrid nanoliquid is strengthened in reaction to higher thermal radiation and Biot number. At the same time, the thermal layer is also strengthened.

Analytical and numerical study of thermo-solutal convection in pulsating flows between two coaxial cylinders

This research reports an analytical and numerical study of thermo-solutal convection in pulsating flows between two coaxial cylinders under a pressure gradient and subject to Dirichlet-type boundary conditions for temperature and concentration along the vertical walls of the annulus. The numerical procedure used in this work is mainly based on the solution of the momentum equations and coupled with the energy and concentration equations. The finite difference method is adopted to solve governing equations using the implicit Crank-Nicolson time marching scheme in the fluid domain and the alternating direction implicit method inside the inner cylinder. The effect of the various parameters such as the fluid-solid conductivity ratio, thermal diffusivity ratio, buoyancy ratio, Lewis number, Richardson number, aspect ratio, and radius ratio on the heat and mass transfer characteristics and the flow structure is presented and discussed. The governing equations are solved analytically after separating into a steady case and an oscillatory case, where an analytical solution for velocity profile, temperature, and concentration distributions is obtained in terms of Bessel’s functions, while the analytical solutions of temperature and concentration profiles are keeping symmetry with the increase of the radius ratio. The results show that the analytical profile can reproduce the three fields obtained numerically and thus for the whole range of parameters.

Analytical model and flow velocity control of electrohydrodynamics system with multi-needle corona discharge

For the flow field distribution and control mechanism generated by the electrohydrodynamics (EHD) system with multi-needle corona discharge, this paper takes the multi-needle EHD pump as the research object, establishes different types of physical models through regional division, constructs multi-physical field coupling relationship, and derives a simplified EHD flow velocity equation suitable for the EHD system with multi-needle corona discharge. Combined with the intelligent optimization method of population evolution, a novel and effective intelligent algorithm is designed for the numerical analysis of the velocity profile distribution of a multi-needle EHD pump, and the flow velocity control law of the multi-needle EHD pump is analyzed by quantitative calculation. The validity of the model and analysis is verified by the electric field and flow field simulation of the multi-needle EHD pump system. The calculation results show that the voltage parameter is more dominant than the electrode spacing parameter in the steady-state flow velocity control of the multi-needle EHD pump, and both the maximum flow velocity and the average flow velocity are superlinearly controlled by voltage. In the design of multi-needle EHD pump with an electrode spacing of 1 cm, the simulation results show that the maximum gas flow velocity of 0.82 m/s can be obtained by providing 5000 V voltage, which verifies the design of a miniaturized multi-needle EHD pump and its feasibility in gas lasers and other application scenarios.

Thermo-magnetic convection of MHD Casson fluid in a wavy triangular porous cavity with embedded a cold inverted triangle obstacle

The design of enclosures is crucial in thermal engineering applications and technologies, encompassing areas such as electronics, heat transfer devices, power reactors, heating systems, solar panels, and nuclear power plants. Thermal efficiency in microchannels is optimized and improved by using triangular enclosures with varying aspect ratios. Specifically, the purpose of these triangular enclosures with cool cylinders is to reduce energy loss in nanoscale thermal sinks and thermal exchange devices. The current study aims to explore the thermal radiation effects on magnetohydrodynamic MHD Casson fluid flow within a wavy triangular cavity that includes an embedded cold inverted triangle. The inner inverted triangle is kept at a lower temperature, while the wavy bottom wall of the outer triangular cavity acts as an isothermal heat source at a higher temperature. The numerical solution for this mathematical model is obtained using the open-source finite element software COMSOL. In this study, the wavy triangular enclosure is analyzed for key parameters such as Casson parameter β , Hartmann number Ha , Rayleigh number Ra , numbers of undulation N , radiation Rd and inclination γ . The study presents the local distribution of streamlines, velocity profiles, isothermals, and entropy production, along with the Nu avg . The results reveal the rate of heat transport and total entropy production raise with the increasing number of undulations N and the Casson parameter β , while they decrease with increasing Hartmann number Ha . The number Nu avg rises with the increasing radiation parameter Rd and Rayleigh number Ra . The maximum stream function is observed at an inclination angle of 60 ° .

Computational investigation of methanol-based hybrid nanofluid flow over a stretching cylinder with Cattaneo–Christov heat flux

Abstract This study investigates heat transfer rates in (AA7075-AA7072/Methanol) hybrid nanofluid flows, considering non-uniform heat sources and Cattaneo–Christov heat flux, with significant implications for aerospace engineering by enhancing thermal management in aircraft engines. The findings could revolutionize automotive cooling system efficiency, optimize heat dissipation in electronic devices, and advance the design of renewable energy systems such as concentrated solar power plants. The study aims to conduct a comparative analysis of (AA7075/Methanol) nanofluid and (AA7075-AA7072/Methanol) hybrid nanofluid flow, examining heat transfer rates, non-uniform heat sources, and Cattaneo–Christov heat flux theory around a stretching cylinder. Thermal radiation and the Biot number are also evaluated. Two different nanoparticles, AA7072 and AA7075, are used with methanol to create AA7075/Methanol nanofluid and AA7075-AA7072/Methanol hybrid nanofluid. The study compresses the resultant non-linear partial differential equation system and applies suitable similarity transformations to reduce the governing partial differential equations with boundary conditions to dimensionless form. The BVP4C shooting method in MATLAB is employed to numerically and graphically solve these dimensionless ordinary differential equations. The results indicate that higher curvature parameter values correlate with increased velocity and temperature distribution profiles. A rise in nanoparticle volume fraction reduces the radial velocity profile but increases the temperature profile. Temperature distribution profiles increase with higher thermal radiation parameter and Biot number values, while higher thermal relaxation parameter values decrease temperature. Additionally, thermal distribution profiles rise with increasing values of both the time-dependent heat source constant and space-dependent heat source parameter.

Cold obstacle influence on nanofluid convection in porous cavity

Enclosure design has a substantial influence on thermal engineering procedures and technology, such as electronics, thermal exchangers, power engines, heating systems, solar panels, and nuclear power plants. Triangular enclosures with different aspect ratios are used for multiple-purpose optimization and enhanced thermal efficiency in microchannels. Triangle enclosures with cold cylinders are often used to reduce heat loss in thermal exchange devices and nanoscale thermal sinks. The objective of the current study is to explore the natural convection of a hybrid nanofluid within a wavy-bottom triangular porous cavity containing an embedded cold inverted triangle, all under the influence of an inclined magnetic field. The inner inverted triangle maintains a lower temperature, while the wavy bottom wall of the outer triangular cavity acts as an isothermal heat source at high temperatures. The space between the inner and outer triangles is filled with hybrid nanofluid (Ag–MgO– water). The numerical solution for the modeled mathematical framework is derived using the open-source finite element program COMSOL. A wavy triangle enclosure is used in this work to analyze key elements, such as the Hartmann number, Ha, the Rayleigh number, Ra, the volume fraction, ϕ, the Darcy number, Da, and the inclination, γ. The local distribution of streamlines, velocity profile, isotherms, and entropy production are demonstrated along with the average Nusselt number. The findings reveal that the heat transfer rate and the total entropy generation increase with increase in Da, while their values decrease with increase in Ha. The value of Nu is raised with increase in the volume fraction ϕ and Rayleigh number Ra. The velocity profile shows increase with increase in the volume fraction ϕ and Rayleigh number Ra.

Impact of Aluminum Oxide & Silicon Dioxide on Nanofluid Flow Over a Stretching Sheet with Heat Transfer: Analytical Solution

A stretchable surface is one of the products features that numerous industrial and engineering field has been taken into consideration due to of its benefit. However, most of the fluid mechanic simulation for stretchable surface has been solved numerically and there is very limited theoretical study discovering this problem. Therefore, the present study investigated the convective Casson nanofluid flow and heat transfer over a linear stretching sheet. The aluminum oxide and silicon dioxide are considered. The analytical resolution of the governing problem yields velocity and temperature solutions using the Laplace transform method. Graphical representation illustrates how nanoparticle volume fraction affects velocity and temperature distribution profiles. Higher nanoparticle volume fractions slow down nanofluid flow and elevate temperature profiles. This investigation establishes a robust foundation for future research utilizing numerical methods.

Experimental and numerical investigation of the elliptical cyclone separator manufactured by 3D printing

Whether the cyclone separators have a high-efficient body shape is a problem that has been ignored for a long time. A series of cyclones with elliptical bodies were designed and manufactured by SLA 3D-printing. The separation performance and flow field of the cyclones were investigated using the experimental and CFD methods, respectively. The detailed flow features, such as streamlines, pressure and velocity profile distribution, and special flow phenomena of the circumferential acceleration/deceleration of the swirling gas, are analyzed. The experimental results reveal that the elliptical cyclones with a/b = 1.2 and 0.83 have about 2% increment of separation efficiency and 43% reduction of pressure drop, as well as satisfactory robustness to the particle properties and operating conditions. The circumferential acceleration/deceleration of the swirling gas creates an additional inertial force for the particles, thereby improving the elliptical cyclones' performance. The results provide innovation ideas for designing and manufacturing the better-performance cyclones.

Experiments investigation on atomization characteristics of a liquid jet in a supersonic combustor

The atomization characteristics of a liquid jet in a supersonic combustor were studied experimentally for the first time. A phase doppler anemometry (PDA) system was utilized for the measurement of droplets properties along the cross-sectional area of spray plumes inside the cavity. The results were obtained under the inflow conditions of Ma = 2.0 supersonic crossflow with a stagnation pressure of 0.55 MPa and a stagnation temperature of 300 K. The size and velocity distribution of droplet inside the cavity are obtained based on the PDA measurements. It was found that the Sauter Mean Diameter (SMD) distribution of droplets inside the cavity ranged from 30 to 55 μm. The average streamwise velocity ranged from −20 to 150 m/s and the average vertical velocity ranged from −20 to 30 m/s. Large droplets distribute in the central area of the cavity. Small droplets spread around the central area of the bottom and sidewall areas of the cavity. The area near the sidewall may be an ideal ignition location due to the lower SMD and velocity of droplets. The time-averaged motion trend of droplets in the cavity is proposed experimentally based on the streamwise and spanwise velocity distribution profiles of droplets. The presence of a recirculation zone within the cavity is confirmed. The recirculation area inside the cavity is mainly distributed in the front half of the cavity. The droplets in the cavity show a good tracking performance. With the effect of the airflow, the droplets in the top area of the cavity move toward the bottom and rear wall of the cavity. In addition, the droplets in the middle and bottom area of the cavity move toward the front wall of the cavity especially for droplets near the sidewall. These universal curves can potentially be used for the modeling of a liquid jet in a supersonic combustor.

3-Dimensional CFD Simulation of Pre-Wastewater Treatment via Multi-Channel Porous Ceramic Membrane

Multi-channel microfiltration (MF) membranes are considered as one of the most efficient separation methods for wastewater treatment, mainly due to their relatively high thermal and chemical resistance. Among various types of MF membranes, Ceramic Membranes attract great attention because of their high active area and superb mechanical strength, making them an industrially applicable pretreatment process for Reverse Osmosis (RO) unit operation. Here, a thorough 3-dimensional modeling of a 19-channel Ceramic Membrane was employed in order to gain insight into pressure drop, velocity distribution, and concentration profile in each channel. Experimental data from a lab-scale multi-channel Ceramic Membrane fed with oily wastewater was used to validate the model. The permeate flux was predicted as 200 to 250 L/m2.hr based on the porous media transmission pressure in such configurations. Further, permeate mass flux was also calculated based on the inlet flow velocities ranging from 0.75 to 2.25 m/s.

Discrete Element Method Modelling of the Particle Flow in Centrifugal Solar Particle Receiver

The centrifugal solar particle receiver (CentRec) is a promising design compared to other particle receiver concepts because it allows for an active adjustment of particle residence time and particle outlet temperature by adjusting the rotational speed of the drum and particle mass flow rate. A Discrete Element Method (DEM) tool is utilized to model the particle flow in CentRec. However, the numerical modeling of the particle flow in large scale receiver is computationally infeasible because of excessive number of particles in the simulation. Thus, in this study, a scale down approach is developed and validated to be used to estimate the particle film characteristics in large scale receivers. The particle velocity profile and film thickness distribution are employed to compare different receiver sizes.

Effects of joule heating and viscous dissipation on electromagneto-hydrodynamic flow in a microchannel with electroosmotic effect: Enhancement of MEMS cooling

This paper inspects the effect of Joule heating and viscous dissipation due to electric double layer (EDL) and electroosmotic effect on steady fully developed electromagnetohydrodynamic flow in a microchannel. Dimensionless formulations of the Poisson-Boltzmann, momentum, and energy equations are derived for the electric potential, velocity profile, and temperature distribution in the microchannel. Exact solutions for the temperature distributions and velocity profile were obtained using the method of undetermined coefficients. The Debye-Hückel linearization is used to get exact solution for the electric potential. The results showed that Brinkmann number [Formula: see text], Joule heating parameter [Formula: see text], Debye-Hückel parameter [Formula: see text], Hartmann number [Formula: see text], and electric field [Formula: see text] have a substantial impact on flow formation and heat transfer. The complex interaction between joule heating, viscous dissipation, and the EOF effect were accurately captured. The range values for the governing parameter for [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] are [Formula: see text], and[Formula: see text] respectively.

Velocity Distribution and Bed Profile Variation for Inbank Flow in a Meandering Channel

Meandering is relatively a common river planform in Malaysia. The sediments transported along the channel due to erosion and deposition are the main reason of meandering river formation. This resulted when the outer bend experienced higher velocities while lower velocities occurred at the inner bend which resulting in sedimentation processes along the river. Hydraulic characteristics in meandering river are considerably more complex and unique as compared to the straight river. Therefore, an experimental investigation was conducted in the Hydraulic Laboratory, UTM Johor Bahru to enhance the understanding of the hydraulics behaviour and morphological changes of an inbank flow in a sand bed meandering channel. Flow classification, streamwise velocity distribution and bed profile changes are addressed in this paper. The findings prevailed that the maximum velocity reduced up to 10% from the upstream to downstream due to the resistance from the meanders. Furthermore, erosion and deposition processes along the channel highly influenced by the velocity distribution. The maximum velocity shifted toward the outer and decreased at the inner of the meander resulting in the deposition and erosion. Higher erosion and deposition were observed at the outer and inner bends, respectively during high flow discharge.

Predicting capillary vessel network hemodynamics in silico by machine learning.

Blood velocity and red blood cell (RBC) distribution profiles in a capillary vessel cross-section in the microcirculation are generally complex and do not follow Poiseuille's parabolic or uniform pattern. Existing imaging techniques used to map large microvascular networks in vivo do not allow a direct measurement of full 3D velocity and RBC concentration profiles, although such information is needed for accurate evaluation of the physiological variables, such as the wall shear stress (WSS) and near-wall cell-free layer (CFL), that play critical roles in blood flow regulation, disease progression, angiogenesis, and hemostasis. Theoretical network flow models, often used for hemodynamic predictions in experimentally acquired images of the microvascular network, cannot provide the full 3D profiles either. In contrast, such information can be readily obtained from high-fidelity computational models that treat blood as a suspension of deformable RBCs. These models, however, are computationally expensive and not feasible for extension to the microvascular network at large spatial scales up to an organ level. To overcome such limitations, here we present machine learning (ML) models that bypass such expensive computations but provide highly accurate and full 3D profiles of the blood velocity, RBC concentration, WSS, and CFL in every vessel in the microvascular network. The ML models, which are based on artificial neural networks and convolution-based U-net models, predict hemodynamic quantities that compare very well against the true data but reduce the prediction time by several orders. This study therefore paves the way for ML to make detailed and accurate hemodynamic predictions in spatially large microvascular networks at an organ-scale.

Characteristics of sodium alginate-based hybrid nanofluid and darcy-forchheimer flow induced by stretching surface with thermal radiation and cattaneo–christov heat flux model

In today's industrial age, one of the most pressing challenges is to find an efficient heat transfer fluid because common fluids don't provide efficient heating and cooling in industries. This paper aims to explore the flow and heat transfer characteristics of (SWCNT-Ag/ Sodium Alginate) and (MWCNT-Cu/ Sodium Alginate) based hybrid nanofluids in the presence of Cattaneo–Christov heat flux model and thermal radiation on a surface. To achieve this, we transform the modeled partial differential equations (PDEs) into ordinary differential equations (ODEs) using suitable similarity variables. These equations are then solved using MATLAB software (bvp4c) to illustrate the influence of important controlling parameters, presented in both tabular and graphical formats. It is noted that raising the Inertia coefficient parameter leads to a drop in the velocity distribution profile of the (SWCNT-Ag/ Sodium Alginate) and (MWCNT-Cu/ Sodium Alginate) based hybrid nanofluid. Enhancing the rotation parameter of (SWCNT-Ag/ Sodium Alginate) and (MWCNT-Cu/ Sodium Alginate) based hybrid nanofluid decreases the velocity distribution profile. The increasing values of the thermal radiation parameter and Biot number increased the thermal distribution profile while the fall down for the enhancing values of the melting parameter. The convergence ranges of emerged flow parameters are listed here(0.1<β<1.4),(0.1<Γ<0.4), (0.1<P<1.3),(0.1<Fr<1.2), (0.01<ϕ1=ϕ2<0.04), (0.4<Me<1.0),(0.1<Bi<2.2),(0.1<Rd<1.2), and (0.4<Ωt<1.0). The key and fascinating aspect of this innovative study is that the heat transfer rate increases for all the parameters involved, aligning with the fundamental goal of utilizing nanofluids in nanotechnology for their promising applications.

Detailed numerical simulation and experiments of a steadily burning micron-sized aluminum droplet in hot steam-dominated flows

Detailed numerical simulations are conducted in comparison with experimental results to study the flame structure and burning rate of a steadily burning aluminum droplet in hot steam-dominated environments. The droplet surface temperature, flame temperature, and flame stabilization position are measured along with the droplet burning rate estimated from the droplet size evolution. A numerical model accounting for detailed transport properties and chemical kinetics is presented and applied to unveil the flame structure, species and temperature distributions, and heat/mass transfer between the droplet and the surrounding gas. The numerical results of the temperature, velocity, and species distribution profiles demonstrate that the aluminum vapor flame is of classical diffusion flame structure, where near the droplet, there is a non-negligible amount of AlOAl apart from the main product Al2O3(l). This supports the deposition and formation of an alumina cap on the surface proposed in the literature. The simulation correctly captured the flame temperature and flame stabilization distance for a range of droplet sizes. Net heat flux analysis shows that conduction heat from the flame front accounts for less than 30% of the heat needed in aluminum evaporation, which warrants further quantification on other heat sources. The experimental and numerical results enrich the knowledge of the heat/mass transfer and chemical reactions near the droplet, which helps deepen the understanding of aluminum droplet burning.