Significance of activation energy and Wu's slip features in Cross nanofluid with motile microorganisms

The current article investigates the impact of the bioconvection in an unsteady flow of magnetized Cross nanofluid with gyrotactic microorganisms and activation energy over a linearly stretched configuration. The analysis has been performed by utilizing the realistic Wu's slip boundary and zero mass flux conditions. The effects of nonlinear thermal radiation and the activation energy are also addressed. The governing flow equations are deduced to a dimensionless form by considering suitable transformations which are numerically targeted via a shooting algorithm. The physical visualization of each physical parameter governing the flow problem has been displayed graphically for distribution of velocity, temperature, concentration and motile microorganisms. The numerical treatment for the variation of skin friction coefficient, local Nusselt number, local Sherwood number and motile density number is performed in tabular forms.     

Influence of bioconvection on Maxwell nanofluid flow with the swimming of motile microorganisms over a vertical rotating cylinder

In recent times, bioconvection phenomenon through the use of nanomaterials has encountered significant manufacturing and technical applications. Bioconvection has several applications in bio-micro-system, due to the enhancement in mass transformation and mixing, which are crucial problems in different micro-systems. The aim of current article is to scrutinize the bioconvection phenomenon in 3D Maxwell nanofluid flow with useful characteristics of mixed convection, activation energy, motile microorganisms and solutal boundary conditions. The flow problem focused on the related laws, outcomes in a series of PDEs which have also been delayed in ODE's structure. The numerical method based on a shooting technique is applied to implement a bvp4c solver using the computational software MATLAB. Shooting tactic is utilized to construct the numerical arrangement of subsequent problem. The mathematical division for the local Nusselt number, the motile microorganism's number, and the local Sherwood number is provided when applying different characteristics to the concerned parameters. The hypothetical simulations mentioned may be more successful in enhancing thermal extrusion mechanisms and solar energy structures. The numerical results regarding flow, thermal field, solutal field and concentration of microorganisms are revealed for growing values of interesting parameters. Furthermore, it is inspected that velocity field dwindles with enlarged variation of Maxwell fluid parameter. It is analyzed that radial velocity of Maxwell nanofluid reduces for larger magnitude of mixed convection parameter. Additionally, temperature profile of species upsurges for larger values of thermal stratification Biot number. Moreover, it is inspected that concentration of species decline for higher estimation of Lewis number while enhanced for activation energy parameter. Microorganisms concentration field of Maxwell nanofluid is detected to be an declining function of Peclet number and bioconvection Lewis number. Angorgeous concurrence is obtained when our accomplished numerical results are compared with an already existed magnitudes in limiting condition; hence dependable results are being eliminated.     

Swimming of micro-organism over an oscillatory stretched surface filled with a magnetic third-grade nanofluid: An application of activation energy

During the past few years, abundant involvement of nanoparticles in improving the thermal extrusion systems and energy resources attracted the attention of numerous scientists recently. The significance of nanofluid in terms of working liquid directed for the enhancement of solar energy and thermal extrusion performances. Therefore, the present analysis deals with the thermal performances of bioconvection flow with nanoparticles suspended in a non-Newtonian fluid. Considering that the flow has been induced due to periodically accelerated surface. The activation energy consequences are also employed in the concentration equation. The flow problem is initially formulated in the form of partial differential equations. The dimensionless variables are reported to renovate such equations in the dimensionless style, which are tackled analytically by employing the homotopy analysis method. The significance of various physical parameters is estimated for the relevant distribution of velocity, temperature, concentration, and motile micro-organisms. The dimensionless local Nusselt number, local Sherwood number, and motile density number are numerically iterated via flow parameters. A convergence analysis is also presented. The detected observation can involve theoretical significance in various engineering processes, bio-fuel cells, solar energy systems, and enhancement of extrusion systems.     

Transition from periodic to non-periodic oscillation observed in a mathematical model of bioconvection by motile micro-organisms

Bioconvection observed in a culture of motile micro-organisms was analyzed numerically. The governing equations are the Navier-Stokes equations with the Boussinesq approximation and a diffusion equation for the motile micro-organism. A transition from a static condition to periodic oscillation was observed according to the increase of the Rayleigh number. It was found that the system of bioconvection could be led into chaotic conditions via a single-frequency oscillatory behavior to a sequence of period-doubling bifurcations by increasing the Rayleigh number, which is analogous to Bénard convection.     

Simultaneous features of Wu's slip,nonlinear thermal radiation and activation energy in unsteady bio-convective flow of Maxwell nanofluid configured by a stretching cylinder

This continuation deals with the bioconvection flow of magnetized Maxwell nanofluid over a stretched cylinder in presence of slip effects. The novel features of activation energy and thermal radiation are also encountered to analyze the flow. The higher order slip relations are introduced to inspect the thermal flow problem. The flow model is developed in terms of dimensionless equations via appropriate variables. The numerical simulations are presented with shooting scheme by using MATLAB software. The physical outcomes of interesting parameters are visualized. The observations show that velocity profile reduces with unsteady parameter, curvature constant and second order slip factor. The temperature profile enhanced with first order velocity slip parameter and curvature constant. Moreover, nanofluid concentration reduces with Lewis number and Brownian constant.     

Study of radiative Reiner–Philippoff nanofluid model with gyrotactic microorganisms and activation energy: A Cattaneo–Christov Double Diffusion (CCDD) model analysis

The nanoparticles play a vital role in the enhancement heat transfer process which is substantial in many industrial and engineering phenomenon's. Moreover, the suspension of nanoparticles with microorganisms is another motivating research area which referred importance in the biotechnology, health sciences and biomedical applications. The aim of this investigation is to present analysis of bioconvection phenomenon for Darcy-Forchheimer flow of Reiner-Philippoff nanofluid induced by a stretched a surface. The contribution of slip via higher relations is dissected for the flow. The radiative pattern is examined for the thermally developed flow. The heat and mass assessment has been examined with help of modified CattaneoChristov expressions. The flow equations associated with momentum, volumetric friction and motile microorganism density is transformed into dimensionless form. Transmuted dimensionless non-linear equations are tracked with shooting technique and results of prominent parameters are sketched via different graphs by using computational software MATLAB. Numerical and graphical tests across macroscopic particles, such as velocity temperature, and the profile of microorganisms, are accessed behind the influence of prominent physical parameters.     

Analysis of onset of bio-thermal convection in a fluid containing gravitactic microorganisms by the energy method

The bio-thermal convection in a suspension containing gravitactic microorganisms saturated by a fluid is investigated within the framework of linear and nonlinear stability theory. Energy method is used for nonlinear stability analysis. Effect of Péclet number (swimming speed of microorganisms) and bioconvection Rayleigh number (concentration of microorganisms) on the stability of the system is analyzed numerically by using the Galerkin weighted residual method. The subcritical region of instability for faster swimmers is large as compared to slowly swimmers. Bioconvection Rayleigh number destabilizes the onset of bio- thermal convection and this effect is more predominant for high speed of microorganisms. The Péclet number, bioconvection Rayleigh number increase the size of cell.     

Thermo-bioconvection transport of nanofluid over an inclined stretching cylinder with Cattaneo–Christov double-diffusion

In this paper, Newtonian nanofluid flow is observed under the effects of the magnetic field, activation energy and motile microorganisms over an inclined stretchable cylinder. The magnificent aspects of nanoliquid are demonstrated by enduring the Brownian motion and thermophoresis diffusion features.Nonlinear higher order partial differential equations are transformed into first-order ordinary differential equations with suitable similarity variables. The attained sets of governing equations are then cracked by bvp4 c procedure in MATLAB mathematical software. The numerical and graphical outcomes of controlling parameters such as Prandtl number, mixed convection, activation energy, thermophoresis,Brownian parameter, Biot number, Lewis number, Peclet number and motile concentration parameter against the velocity, temperature, volumetric concentration and motile concentration of nanoparticles of the fluid are discussed. The velocity is enhanced with the growth valuation in mixed convection and decay by rising variation of buoyancy ratio parameter, magnetic parameter and bio-convective Rayleigh parameter. The evolution in motile microorganisms is due to the increasing values of microorganisms Biot number. The presented data can be helpful in enhancement of manufacturing processes, biomolecules, extrusion systems applications and energy production improvement.     

Transport phenomena of carbon nanotubes and bioconvection nanoparticles on stagnation point flow in presence of induced magnetic field

This article is a numerical study of stagnation point flow of carbon nanotubes over an elongating sheet in presence of induced magnetic field submerged in bioconvection nanoparticles. Two types of carbon nanotubes are considered i.e. single wall carbon nanotube and multi wall carbon nanotube mixed in based fluid taken to be water as well as kerosene-oil. The emphasis of present study is to examine effect of induced magnetic field on boundary layer flows along with influence of SWCNT and MWCNT. Physical problem is mathematically modeled and simplified by using appropriate similarity transformations. Shooting method with Runge-Kutta of order 5 is employed to compute numerical results for non-dimensional velocity, induced magnetic field and temperature. The effects of pertinent parameters are portrayed through graphs. Numerical values of skinfriction coefficient and Nusselt number are tabulated to study the behaviors at the stretching surface. It is depicted that induced magnetic field is an increasing function of solid nanoparticles volumetric fraction. Moreover, MWCNT contributes in rising induced magnetic field more as compared to SWCNT for both water and kerosene-oil based fluids.     

Entropy generation (irreversibility) associated with flow and heat transport mechanism in Sisko nanomaterial

Here a novel applications of entropy generation optimization is presented for nonlinear Sisko nanomaterial flow by rotating stretchable disk. Flow is examined in the absence of magnetohydrodynamics and Joule heating. Total irreversibility rate (entropy generation rate) is investigated for different flow parameters. Heat source/sink and viscous dissipation effects are considered. Impacts of Brownian motion and thermophoresis on irreversibility have been analyzed. Governing flow equations comprise momentum, energy and nanoparticle concentration. Von Karman's similarity variables are implemented for reduction of PDEs into ODEs. Homotopy analysis technique for series solutions is implemented. Attention is given to the irreversibility. The impacts of different flow parameters on velocity, nanoparticle concentration, temperature and irreversibility rate are graphically presented. From obtained results it is examined that irreversibility rate enhances for larger estimation of Brinkman number and diffusion. Furthermore it is also examined that temperature and nanoparticle concentration show contrast behavior through Prandtl number and Brownian motion.     

New thermodynamics of entropy generation minimization with nonlinear thermal radiation and nanomaterials

This research addressed entropy generation for MHD stagnation point flow of viscous nanofluid over a stretching surface. Characteristics of heat transport are analyzed through nonlinear radiation and heat generation/absorption. Nanoliquid features for Brownian moment and thermophoresis have been considered. Fluid in the presence of constant applied inclined magnetic field is considered. Flow problem is mathematically modeled and governing expressions are changed into nonlinear ordinary ones by utilizing appropriate transformations. The effects of pertinent variables on velocity, nanoparticle concentration and temperature are discussed graphically. Furthermore Brownian motion and thermophoresis effects on entropy generation and Bejan number have been examined. Total entropy generation is inspected through various flow variables. Consideration is mainly given to the convergence process. Velocity, temperature and mass gradients at the surface of sheet are calculated numerically.     

An Optimal Analysis for 3D Flow of Prandtl Nanofluid with Convectively Heated Surface

In this paper,the magnetohydrodynamic 3 D flow of Prandtl nanoliquid subject to convectively heated extendable surface has been discussed.A linear stretching surface makes the flow.Thermophoretic and Brownian motion impacts are explored.Heat transfer for convective procedure is considered.Prandtl liquid is taken electrically conducted through applied magnetic field.Suitable non-dimensional variables lead to strong nonlinear ordinary differential system.The obtained nonlinear differential systems are solved through optimal homotopic technique.Physical quantities like skin friction coefficients and Nusselt number are explored via plots.It is observed that effects of Hartman parameter and Biot number on temperature and concentration are quite similar.Both temperature and concentration are enhanced for larger values of Hartman parameter and Biot number.     

Numerical simulation and experimental validation of multiphysics field coupling mechanisms for a high power ICP wind tunnel

We take the established inductively coupled plasma(ICP) wind tunnel as a research object to investigate the thermal protection system of re-entry vehicles. A 1.2-MW high power ICP wind tunnel is studied through numerical simulation and experimental validation. The distribution characteristics and interaction mechanism of the flow field and electromagnetic field of the ICP wind tunnel are investigated using the multi-field coupling method of flow, electromagnetic, chemical, and thermodynamic field. The accuracy of the numerical simulation is validated by comparing the experimental results with the simulation results. Thereafter, the wind tunnel pressure, air velocity, electron density, Joule heating rate, Lorentz force, and electric field intensity obtained using the simulation are analyzed and discussed. The results indicate that for the 1.2-MW ICP wind tunnel, the maximum values of temperature, pressure, electron number density, and other parameters are observed during coil heating. The influence of the radial Lorentz force on the momentum transfer is stronger than that of the axial Lorentz force. The electron number density at the central axis and the amplitude and position of the Joule heating rate are affected by the radial Lorentz force. Moreover, the plasma in the wind tunnel is constantly in the subsonic flow state, and a strong eddy flow is easily generated at the inlet of the wind tunnel.     

Modeling Chemically Reactive Flow of Sutterby Nanofluid by a Rotating Disk in Presence of Heat Generation/Absorption

In this article we investigate the flow of Sutterby liquid due to rotating stretchable disk. Mass and heat transport are analyzed through Brownian diffusion and thermophoresis. Further the effects of magnetic field, chemical reaction and heat source are also accounted. We employ transformation procedure to obtain a system of nonlinear ODE's. This system is numerically solved by Built-in-Shooting method. Impacts of different involved parameter on velocity, temperature and concentration are described. Velocity, concentration and temperature gradients are numerically computed. Obtained results show that velocity is reduced through material parameter. Temperature and concentration are enhanced with thermophoresis parameter.     

Entropy generation in radiative motion of tangent hyperbolic nanofluid in presence of activation energy and nonlinear mixed convection

In this communication, an optimization of entropy generation is performed through thermodynamics second law. Tangent hyperbolic nanomaterial model is used which describes the important slip mechanism namely Brownian and thermophoresis diffusions. MHD fluid is considered. The novel binary chemical reaction model is implemented to characterize the impact of activation energy. Nonlinear mixed convection, dissipation and Joule heating are considered. Appropriate similarity transformations are implemented to get the required coupled ODEs system. The obtained system is tackled for series solutions by homotopy method. Graphs are constructed to analyze the impact of different flow parameters on entropy number, nanoparticle volume concentration, temperature and velocity fields. Total entropy generation rate is calculated via various flow variables. It is noticed from obtained results that entropy number depend up thermal irreversibility, viscous dissipation and Joule heating irreversibility and concentration irreversibility. Decreasing behavior of concentration is witnessed for higher estimations of chemical reaction variable. Entropy number is more for higher Hartmann number, Weissenberg number and chemical reaction variable while contrast behavior is noted for Bejan number.     

Effect of Hall and ion-slip on the peristaltic transport of nanofluid: A biomedical application

The peristaltic flow of viscous nanofluid in a channel with compliant walls is examined. The flow analysis is presented in the presence of Hall and ion-slip effects. The resulting equations through long wavelength and low Reynolds number approaches are solved. Stream function is obtained in closed form. Attention has been given to the influence of Brownian motion, thermophoresis and Hall and ion slip parameters on the velocity, temperature and concentration profiles. The results show an affective increase in the temperature and nanoparticles concentration with the increase in the strength of Brownian motion effects. Similar results are observed for Hall and ion slip parameters. Further heat transfer coefficient is an increasing function of Hall and ion-slip parameters. Also decrease in the size of trapped bolus is shown for Hall and ion-slip parameters.     

Gas flow through a slit into a vacuum in a wide range of rarefaction

Gas flow through a two-dimensional slit into a vacuum is investigated by a direct simulation Monte Carlo method. Results for the mass flow rate are obtained as a function of the rarefaction parameter, which is inversely proportional to the Knudsen number. The distributions of density, temperature and mass velocity, and streamlines are presented. In the free molecular flow regime and in the hydrodynamic limit, our results agree with theoretical asymptotes, and in the transition regime, they compare well with numerical simulations by other authors. The text was submitted by the author in English.     

Advanced Study of Unsteady Heat and Chemical Reaction with Ramped Wall and Slip Effect on a Viscous Fluid

This paper investigate the effect of slip boundary condition, thermal radiation, heat source, Dufour number,chemical reaction and viscous dissipation on heat and mass transfer of unsteady free convective MHD flow of a viscous fluid past through a vertical plate embedded in a porous media. Numerical results are obtained for solving the nonlinear governing momentum, energy and concentration equations with slip boundary condition, ramped wall temperature and ramped wall concentration on the surface of the vertical plate. The influence of emerging parameters on velocity,temperature and concentration fields are shown graphically.     

实验条件对二氧化钛纳米棒形貌和光电流密度的影响

采用简单的水热合成法,以四异丙醇钛为钛源,制备出整齐有序的二氧化钛纳米棒阵列。探索了钛源浓度、反应液酸度、反应时间、温度等实验条件对纳米棒的形貌和光电流密度的影响。实验结果表明:钛源浓度和反应液酸度对纳米棒的生长有非常大的影响,最佳反应液的组分为10 mL去离子水、10 mL盐酸和0.4 mL钛源。另外,随着反应时间的增加,纳米棒的长度会明显的增加,但纳米棒的直径和光电流密度却变化不大。同时,纳米棒的长度也随着反应温度的增高而增加,其光电流密度随之呈现先增大后减小的趋势,但其直径没有明显改变。