Drag Rate Research Articles

Mixed convection hybrid nanoliquid flow over an exponentially stretching rough (smooth) surface with the impacts of homogeneous–heterogeneous reactions

AbstractThis paper explores the influence of homogeneous and heterogeneous (surface) reactions in the mixed convection flow of hybrid nanoliquid (Cu–Fe3O4/water) over an exponentially stretching surface. In this analysis, we have considered chemical species of unequal diffusivity. In spite of this, the effects of surface roughness and surface mass transfer are also included in the analysis. The numerical solutions to the transformed governing equations of the physical problem have been obtained by employing the implicit finite difference method and the quasilinearization technique. The numerical results for drag coefficient and rate of transfer of heat, along with various profiles such as velocity, temperature, and species concentrations, for some appropriate parameters are displayed by graphs and tables. The rate of transfer of heat from rough (smooth) surfaces to the liquid in the case of hybrid nanoliquid is found to be greater as compared to the nanoliquid (Fe3O4/water) and base liquid (water). Where as, opposite trend is observed for skin friction co–efficient. The influence of heterogeneous reaction on the reactant (bulk liquid) is found to be significantly high as compared to the homogeneous reaction in the regime of the boundary layer. The obtained numerical outcomes are compared with those of earlier literature and are found to be in good agreement.

Numerical and linear regression analysis on MHD two‐phase flow in an asymmetric nonuniform channel

AbstractThe flow through asymmetric nonuniform (convergent) channels with the effect of the magnetic field have a pronounced impact in engineering and biological fields such as chemical and food industries, blood flow through capillaries, and arteries, and so forth. With this motivation, the present study focuses on convective hydromagnetic particulate suspension flow in an asymmetric convergent channel under the heat generation effect. The numerical method is applied to solve the nondimensionalized equations governing the transport process of fluid and particle flow and its heat. To check the convergence of the computational results, a grid independence test has been performed. A comparison test has been made to validate the results and an admirable agreement is noticed with published results. Computation results are reported for the influence of emerging parameters on the fluid as well as particle velocity and temperature profiles through graphs and tables. A method of slope linear regression through data points is presented to study the impact of various parameters on skin friction and Nusselt number. The study pioneers the investigation on the significance of the combined influence of cross‐flow Reynolds number and magnetic field on fluid and particle in the convergent channel and also reports its importance on drag coefficient and rate of heat transfer at the walls. It is perceived that a reduction in fluid velocity takes place with an increment in Magnetic parameter, Grashof number, and Reynolds number. An augmentation in fluid temperature is noted with an increment in Prandtl number and heat source parameter.

Darcy–Forchheimer flow of Ree–Eyring fluid over an inclined plate with chemical reaction: A statistical approach

AbstractIn spite of various reports on non‐Newtonian fluids, little is known on the impact of chemical reaction on the Darcy–Forchheimer flow of Ree–Eyring fluid when Cattaneo–Christov (C‐C) heat flux (HF) is significant. The inclusion of porous medium occurs in various procedures which include heat transfer, geophysics design, and so forth. It also influences oil production recovery, energy storage units, solar receivers, and many others. The Darcy–Forchheimer flow model is important in the fields where a high flow rate effect is a common phenomenon, for instance, in petroleum engineering. In this study, we aim to analyze the dissipative Darcy–Forchheimer flow of Ree–Eyring fluid by an inclined (stretching) plate with chemical reaction. We have included the C‐C HF model to investigate the heat transfer characteristics of the fluid. Equations in the mathematical model are metamorphosed as ordinary differential equations and then unriddled with the aid of shooting strategy. The main advantage of the shooting method is that it is easy to apply. The shooting method requires good initial guesses for the first derivative and can be applied to both linear and nonlinear problems. Results are explicated through graphs. We took the help of a statistical tool, that is, correlation coefficient to analyze the impression of crucial parameters on surface friction drag (skin friction coefficient), heat and mass transfer rates. The main inferences of this study are porosity parameter and Forchheimer numbers deprecate the fluid velocity, Eckert number ameliorates fluid temperature and concentration minifies with larger chemical reaction parameter. It is discovered that the Forchheimer and Weissenberg numbers deprecate the surface friction drag. Mass transfer rate has a substantial positive relationship with Schmidt number and chemical reaction. Furthermore, the heat transfer rate has a substantial positive correlation with the thermal relaxation parameter and a substantial negative correlation with the Eckert number.

Study on heat transfer aspects of solar aircraft wings for the case of Reiner-Philippoff hybrid nanofluid past a parabolic trough: Keller box method

Solar energy is the major source of heat energy from the sun having immense utilization in technologies like photovoltaic cells, solar energy plates, solar street lights, solar water pumping, and so on. How to maximize the heat energy which is later on used as electrical energy for many purposes in solar aircraft is the hot topic of research in this decade. The current paper is about the study of entropy generation analysis and hybrid nano-solid particles impact on parabolic trough surface collector (PTSC) located inside the solar aircraft wings. homo/heterogeneous reactions have been taken. Non-Newtonian Reiner-Philippoff model along with porous medium and Darcy-Forchheimer effects have been taken into account for the present study. The heat transfer performance of the solar aircraft wings has been enhanced with the inclusion of effects like hybrid nanoparticles, thermal radiations, variable thermal conductivity, and viscous dissipation. By utilizing the proper conversions the demonstrated partial-differential equations are renovated into ordinary-differential formulas and tackled numerically with the utilization of well established numerical scheme termed as Keller-Box method. The impact of dimensionless sundry parameters on velocity, shear stress, temperature, homo/heterogeneous as well as surface drag and heat transfer rates are sketched through tables and figures. A positive variation in thermal radiation, thermal conductivity, and viscous dissipation effects enhances the heat transfer rate inside the solar aircraft wings.

A Computational Model for the Radiated Kinetic Molecular Postulate of Fluid-Originated Nanomaterial Liquid Flow in the Induced Magnetic Flux Regime

The performance of mass transfer rate, friction drag, and heat transfer rate is illustrated in the boundary layer flow region via induced magnetic flux. In this recent analysis, the Buongiorno model is introduced to inspect the induced magnetic flux and radiative and convective kinetic molecular theory of liquid-initiated nanoliquid flow near the stagnant point. The energy equation is modified by radiation efficacy using the application of the Rosseland approximation. Through similarity variables, the available formulated partial differential equations are promoted into the nondimensional structure. The variation of the induced magnetic field near the wall goes up, and very far away, it decays when the size of the radiation characteristic ascends. The velocity amplitude expands by enlargement in the amount of the magnetic parameter, mixed convection, thermophoresis parameter, and fluid characteristic. The nanoparticle concentration reduces if the reciprocal of the magnetic Prandtl number expands. The temperature spectrum declines by enhancing the amount of the magnetic parameter. Drag friction decreases by the increment in the values of radiation and thermophoresis parameters. Heat transport rate increases when there is an increase in the values of Brownian and magnetic parameters. Mass transfer rate increases when there is incline in the values of the magnetic Prandtl and fluid parameter.

Mixed convection and melting rheology in dual stratified Eyring-Powell nanofluid flow over surface of variable thickness: Buongiorno model approach

Eyring Powell fluid flow over linear as well as nonlinear stretching surfaces has been discussed in literature by several researchers. However, lesser attention has been paid for such studies with surfaces comprising variable thickness. Present communication inculcates the novel features regarding melting heat transport in Eyring Powell nanofluid over a surface of variable thickness while keeping in view the aspects of radiative heat transfer. Influence of thermophoresis and Brownian motion phenomena is discussed by making use of Buongiorno model approach. Here, the flow characteristics are analyzed in mixed convective and dual stratified porous medium. Appropriate transformations are imposed in order to convert partial differential equations to ordinary differential equations possessing highly nonlinear form. Homotopy analysis method is utilized to achieve desired convergent series solutions. Impact of several emerging variables on velocity temperature and concentration distributions is analyzed graphically. Expressions for drag force and rate of heat transfer are evaluated and demonstrated graphically. Nano particle concentration increases for higher Brownian motion parameter. Enriched thermal field is attained due to rise in thermophoretic parameter. However, recessive behavior of velocity profile results due to higher fluid parameters. Thermal field rises as a result of larger values of mixed convection parameter while it decays gradually for enhanced melting parameter.

Conventional anddata‐drivenmodeling of filtered drag, heat transfer, and reaction rate ingas–particleflows

AbstractThis study presents conventional and artificial neural network‐based data‐driven modeling (DDM) methods to model simultaneously the filtered mesoscale drag, heat transfer and reaction rate in gas–particle flows. The dataset used for developing the DDM is filtered from highly resolved simulations closed by our recently formulated microscopic drag and heat transfer coefficients (HTCs). Results reveal that the filtered drag correction is nearly independent of filter size when including the filtered gas phase pressure gradient. We further find that the filtered HTC correction critically depends on the added filtered temperature difference marker while the filtered reaction rate correction shows weak dependence on the additional markers. Moreover, compared with conventional correlations, DDM predictions agree better with filtered resolved data. Comparative analysis is also conducted between existing HTC corrections and our work. Finally, the applicability of conventional and data‐driven models coupled with coarse‐grid computational fluid dynamics simulations for pilot‐scale (reactive) gas–particle flows is validated comprehensively.

Numerical Solution of Laminar Flow and Heat Transfer over a Flat Plate in a Nonuniform Stream.(Dept.M)

The laminar flow and heat transfer over an isothermal flat plate in a free stream with nonuniform velocity have been analysed, fully implicit numerical method (with a hybrid representation for the convective term normal to the streamwise direction) is used for solving the governing equations. Two practical cases are considered. In the first case, a flat plate is located in the laminar wake of an upstream plate. In the second case, a flat plate 18 inserted in the laminar shear layer joining a uniform stream and a quiescent fluid. The dependence of the boundary-layer and heat transfer on the lateral and the downstream shifts of the plate have been investigated. It was found that the nonuniformity of the free stream velocity causes reductions in both the wall shear stress and heat transfer relative to the corresponding values for uniform free stream. These relative reductions decrease with increasing downstream distance along the plate in the upper half of the wake. In the lower half of the wake, these Zeductions increase with distance along the plate. It was also found that the minimum values for drag and overall heat transfer rate at a certain streamwise location correspond to a slight downward shift of the plate from the wake centreline. In the case of shear layer, the relative reductions in the wall shear and heat transfer are more pronounced in the low velocity region. These reductions decrease with increasing downstream distance along the plate. It was found that both the drag and overall heat transfer rate decrease continuously with downstream shift of the plate.

Hydrothermal and entropy production analyses of magneto-cross nanoliquid under rectified Fourier viewpoint: A robust approach to industrial applications

The present article has been groomed to explore the boundary-driven magnetized flow of cross nanoliquid over thin needle subject to auto catalysis chemical reactions. In addition to it, the effect of entropy optimization model is incorporated and transportation of heat under non-uniform heat source/sink, Cattaneo-Christov heat flux (rectified Fourier) viewpoint (CCHF), and non-linear thermal radiation is also taken into account. Furthermore, the Brownian and thermophoresis aspects of nanoliquid are invoked. The dimensionless governing equations are solved by apposite shooting scheme. The outcomes of the present study via demonstrated graphs and numerical benchmarks seem to indicate that controlled Sakiadis and Blausius flow pattern of cross nanofluids is attained due to incremented magnetic field strength. Temperature ratio parameter contributes the upgradation of thermal boundary layer thickness and homogenous reaction rate leads to the diminution of nanoparticles concentration. The relative values of needle velocity and the velocity of cross nanofluid are most important factor for the regulation of viscous drag force and rate of heat transportation. Augmented Weissenberg parameter and Reynolds number are the prime factor for the uplift of the flow field and the related layer thickness. Furthermore, the existence of CCHF could result in augmentation in Nusselt.

Bio-convective and chemically reactive hybrid nanofluid flow upon a thin stirring needle with viscous dissipation

In this work, the thermal analysis for bio-convective hybrid nanofluid flowing upon a thin horizontally moving needle is carried out. The chemical reaction and viscous dissipation has also considered for flow system in the presence of microorganism. The hybrid nanoparticles comprising of Copper left( {Cu} right) and Alumina left( {Al_{2} O_{3} } right) are considered for current flow problem. Mathematically the flow problem is formulated by employing the famous Buongiorno’s model that will also investigate the consequences of thermophoretic forces and Brownian motion upon flow system. Group of similar variables is used to transform the model equations into dimensionless form and have then solved analytically by homotopy analysis method (HAM). It has established in this work that, flow of fluid declines due to increase in bioconvection Rayleigh number, buoyancy ratio and volume fractions of nanoparticles. Thermal flow grows due to rise in Eckert number, Brownian, thermophoresis parameters and volume fraction of nanoparticles. Concentration profiles increase due to growth in Brownian motion parameter and reduces due to increase in thermophoresis parameter and Lewis number. Motile microorganism profile declines due to augmentation in Peclet and bioconvection Lewis numbers. Moreover, the percentage enhancement in the drag force and rate of heat transfer using conventional nanofluid and hybrid nanofluid are observed and discussed. The hybrid nanofluid increases the skin friction and heat transfer rate more rapidly and efficiently as compared to other traditional fluids. A comparison of the present study with the existing literature is also conducted with a closed agreement between both results for variations in thickness of the needle.

Impacts of heterogenous-homogeneous reactions in the flow of Prandtl nanofluids with convective heating process

This research article discusses the 3-D flow of magnetized Prandtl nanoliquid by convectively heated surface utilizing homogeneous-heterogeneous reactions. An extendable surface produces the flow. Thermophoresis and random development are investigated. Thermal transport for the convective method is accounted. The Prandtl material is an electrical conducting via applying a magnetic field. Appropriate non-dimensional factors correspond to the non-linear differential equations. Acquired non-linear differential frameworks are comprehended via the optimal homotopic procedure. Physical amounts like surface drag force and rate of the heat transfer are investigated through sketches. It is seen that the impacts of Biot and Hartman numbers on the concentration and the temperature are very comparative. Both the concentration and the temperature are improved for growing estimations of Biot and Hartman numbers.

Three Dimensional Magnetohydrodynamic Stretched Flow of Cross Nanofluids

The purpose of the present study is to analyze the flow, heat and mass transfer characteristics in the three dimensional magnetohydrodynamic stretched flow of Cross nanofluids. In the present study, Brownian movement, thermophoresis, thermal and solute convective boundary conditions are considered. With boundary layer approximation and self-similarity transformations, the non dimensional nonlinear governing equations are solved via shooting iteration technique together with 4th order Runge-Kutta integration scheme. The impact of developed physical parameters on velocity, temperature, concentration, surface viscous drag, heat and mass transfer rates has been examined via appropriate graphs and discussions. The numerical results indicate that uplift in the magnetic field strength and Weissenberg number diminishes the axial and transverse velocity fields. Further, the temperature ratio parameter brings about substantial improvement to the temperature and the related layer. The outcomes of the present study provide significant contribution to the controlled fluid motion and regulating the rate of heat transportation from the solid boundary into the boundary layer.

Interaction between granular flows and flexible obstacles: A grain-scale investigation

Flexible obstacles are used to reduce the impact load exerted by granular flows. However, grain-scale interactions between granular assemblies and flexible obstacles remain poorly understood, making it difficult to estimate the required resisting force. In this fundamental study, a flexible obstacle was simplified as a grain intruder and dragged through a static granular assembly. A new physical intruder apparatus was used to calibrate a discrete element model. The calibrated model was then used to evaluate the effects of the stiffness and loading rate on the force experienced by the intruder and the energy dissipated by the granular assembly. The response of the intruder and the granular assembly depended significantly on both the drag rate and the obstacle stiffness. Softer obstacles caused longer sticks between slips. At least 60% of the work was transferred from the intruder into the granular assembly regardless of the drag rate and obstacle stiffness. Stick-slip behaviour was not observed for stiff obstacles and high drag rates (>1 m/s), where the bulk granular assembly fluidised. The results of this study suggest that rigid obstacles are better for causing energy dissipation in the granular assembly, while flexible obstacles are better for reducing the resisting forces required.

Thermophoresis and Brownian Model of Pseudo-Plastic Nanofluid Flow over a Vertical Slender Cylinder

This study focuses on the industrial and engineering interest quantities, such as drag force and rate of transmission of heat, for pseudo-plastic nanofluid flow. The attributes of natural convection of the pseudo-plastic nanofluid flow model over a vertical slender cylinder are explored. The pseudo-plastic flow is studied under the influence of concentration of nanoparticles, rate of heat transmission, and drag force. For the first time, the pseudo-plastic nanofluid flow model has been implemented over a vertical slender cylinder which is not yet investigated. The acquired model is based on thermophoresis and Brownian motion mechanisms. The governing equations of pseudo-plastic nanofluid in cylindrical coordinates are modelled. The developed system of nonlinear equations is tackled by boundary layer assumptions and similarity transformations. Moreover, the solution of the acquired system exhibited by using a new powerful numerical technique. A comprehensive debate on drag force and transmission of heat under the influence of various emerging parameters is illustrated in the table. Furthermore, the effects of dimensionless parameters over the velocity profile, temperature profile, and concentration of nanoparticle profile have been exhibited graphically.

Common-envelope Dynamics of a Stellar-mass Black Hole: General Relativistic Simulations

Abstract With the goal of providing more accurate and realistic estimates of the secular behavior of the mass accretion and drag rates in the “common-envelope” scenario encountered when a black hole or a neutron star moves in the stellar envelope of a red supergiant star, we have carried out the first general relativistic simulations of the accretion flow onto a nonrotating black hole moving supersonically in a medium with regular but different density gradients. The simulations reveal that the supersonic motion always rapidly reaches a stationary state and produces a shock cone in the downstream part of the flow. In the absence of density gradients we recover the phenomenology already observed in the well-known Bondi–Hoyle–Lyttleton accretion problem, with super-Eddington mass accretion rate and a shock cone whose axis is stably aligned with the direction of motion. However, as the density gradient is made stronger, the accretion rate also increases and the shock cone is progressively and stably dragged toward the direction of motion. With sufficiently large gradients, the shock-cone axis can become orthogonal to the direction, or even move in the upstream region of the flow in the case of the largest density gradient. Together with the phenomenological aspects of the accretion flow, we have also quantified the rates of accretion of mass and momentum onto the black hole. Simple analytic expressions have been found for the rates of accretion of mass, momentum, drag force, and bremsstrahlung luminosity, all of which have been employed in the astrophysical modeling of the secular evolution of a binary system experiencing a common-envelope evolution. We have also compared our results with those of previous studies in Newtonian gravity, finding similar phenomenology and rates for motion in a uniform medium. However, differences develop for nonzero density gradients, with the general relativistic rates increasing almost exponentially with the density gradients, while the opposite is true for the Newtonian rates. Finally, the evidence that mass accretion rates well above the Eddington limit can be achieved in the presence of nonuniform media increases the chances of observing this process also in binary systems of stellar-mass black holes.

Modeling the effects of drillstring eccentricity, pipe rotation and annular blockage on cuttings transport in deviated wells

Transportation of drilled cuttings from the bit to the surface is one of the primary functions of a drilling fluid. This transport is facilitated primarily by pump rate and the rheology and density of the drilling fluid, which all contribute to cuttings lift. There are, however, other important factors that have a significant effect on cuttings transport, as shown by a large amount of academic and industry research. These include rotation and the eccentricity of the drillstring. These two parameters are interrelated when it comes to hole cleaning: the effect of pipe rotation on cuttings evacuation changes with varying eccentricity. This adds a level of complexity to the hole cleaning challenge, both from a modeling perspective as well as the practical management of cuttings evacuation from wells in the field.A novel cuttings transport model that includes essential effects such as pipe rotation, eccentricity and annulus blockage is presented in this study. Velocity profiles for the well annulus subdivided into small grids are calculated for any given fluid, which can be a Newtonian or a non-Newtonian fluid such as described by the Bingham Plastic, Power Law or Yield Power Law rheological models. These local velocities are compared against the concept of the critical velocity for cuttings transport. Then, the locations of the settled cuttings and the magnitude of annular blockage are calculated numerically. Continuity and momentum equations are solved for the blocked annulus to estimate the new local velocities. By doing so, a realistic representation of a wellbore's pressure and velocity profiles is obtained. The work aims to make hole cleaning modeling more comprehensive and representative in order to prevent hole cleaning-related non-productive time (NPT) or invisible lost time (ILT) events in the field. These include stuck pipe and lost circulation events, low rates of penetration, high torque and drag, failure to land the casing at the desired depth, and poor cement jobs leading in turn to poor zonal isolation.

Coulomb drag between a carbon nanotube and monolayer graphene

We study Coulomb drag in a system consisting of a carbon nanotube (CNT) and monolayer graphene. Within the Fermi liquid theory we calculate the drag resistivity and find that the dimensional mismatch of the system components leads to a dependence of the drag rate on the carrier density, temperature, and spacing, which is substantially different from what is known for graphene double layers. Due to the competing effects of forward and backward scattering, we identify new features of the drag dependence on the electron density, which allows us to control their relative contribution to the drag resistivity.

Activation energy on MHD flow of titanium alloy (Ti6Al4V) nanoparticle along with a cross flow and streamwise direction with binary chemical reaction and non-linear radiation: Dual Solutions

In this work, efforts are made to scrutinize the influence of MHD on nonlinear radiative flow comprising Ti6Al4V nanoparticle through streamwise direction along with a crossflow. Activation energy with binary chemical reaction is also explored through cross-flow comprising Ti6Al4V nanoparticle which has not been discussed yet. Similarity variables are employed to transform PDEs into nonlinear ODEs system. Then, it executed numerically through bvp4c from Matlab. Multiple solutions analysis is used to obtain first and second solutions. Influences of controlling non-dimensional parameters on liquid velocity and fluid temperature are scrutinized through the assist of diagrams. Results disclose that the drag surface force and rate of heat transfer increase for greater values of suction, while the rate of mass transfer decreases. Besides, multiple results are noticed for certain values of the moving parameter.

Analysis of entropy generation for MHD flow of third grade nanofluid over a nonlinear stretching surface embedded in a porous medium

The main focus of present research work is to elaborate magnetohydrodynamic flow of third grade nanofluid with activation energy and binary chemical reaction. Fluid flow is generated by a nonlinearly stretched surface. Temperature and nano-concentration distributions are analyzed in the presence of Brownian motion and thermophoresis effects. The effects of Joule heating, thermal radiation and porous medium are further investigated for current analysis. Thermodynamic second mechanism is utilized to explore entropy generation rate of the system. Newly developed condition having zero mass flux of nanoparticles at the boundary is also incorporated. Partial differential equations governing the flow problem has been converted into ordinary ones using appropriate similarity variables. Builtin Shooting technique via NDsolve has been used to construct the numerical solution of the resulting problem. Impacts of various physical flow parameters are presented graphically for temperature, nano-concentration, surface drag coefficient and rates of heat trasnfer and entropy generation. It is found that impacts of third grade parameters on the thermal and nano-concentration fields are quite similar. Temperature, concentration and associated layer thicknesses are reduced via higher third grade parameters. It is established that the magnetic field restricts the flow strongly and serves as a potent control mechanism. It can be concluded that an applied magnetic field will play a major role in applications like micropumps, actuators and biomedical sensors. The activation energy aspect reduces the concentration boundary layer thickness. Total entropy of the entire system increases against higher values temperature difference variable, Brinkman number, porosity parameter, radiation parameter and magnetic parameter.

Simulation of Cattaneo–Christov heat flux on the flow of single and multi-walled carbon nanotubes between two stretchable coaxial rotating disks

With an objective to unfold the flow and heat transfer characteristics of carbon nanotubes between two stretchable coaxial rotating disks, the present investigation has been carried out. The behavior of single- and multi-walled carbon nanotubes (SWCNTs and MWCNTs) taking water as the base fluid is analyzed. To formulate the energy equation, we have incorporated Cattaneo–Christov heat flux model. Consideration of such kind of model accounts the contribution by thermal relaxation. von Karman transformation has been implemented in order to reconstruct the governing partial differential equations into a system of ordinary differential equations. Employing optimal homotopy analysis method series solutions are obtained. Error analysis has also been performed and presented in tabular form. The physical clarifications for the behavior of fluid velocity, temperature, skin friction coefficient and Nusselt number are well demonstrated with the help of graphs and contour plots. One of the major outcomes of the present study signifies that water-based SWCNTs have a tendency to cause less drag and higher rate of heat transfer as compared to water-based MWCNTs. This investigation finds numerous applications in different mechanisms of thermal conversion for nuclear propulsion and spacecraft.