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Using incompressible smoothed particle hydrodynamics (ISPH), this study examines the bioconvection flow of oxytactic microorganisms in a porous annulus populated by nano-encapsulated phase change material (NEPCM). Artificial neural network (ANN) is joined with the ISPH method to accurately predict the values of average N u ‾. Between the outside hexagonal-shaped domain and the embedded wavy cylinder, a new annulus is produced. The ranges of the pertinent parameters are wave amplitude of an embedded cylinder A = 0.1 − 0.5 , Hartmann number H a = 0 − 80 , a radius of the cylinder R c y l d = 0.05 − 0.5 , Darcy number D a = 10 − 2 − 10 − 5 , undulation number K u n d = 2 − 32 , bioconvection Rayleigh number R a b = 1 − 1000 , Rayleigh number R a = 10 3 − 10 6 , and Lewis number L e = 1 − 20. The regulated geometric characteristics of an embedded wavy cylinder, such as wavy amplitude, cylinder radius, and undulation numbers, have been found to contribute significantly to widening the cooling region and minimizing the oxytactic microorganisms. Hence, the embedded wavy cylinder can be applied for various thermal uses including cooling devices and heat exchangers. The average N u ‾ is enhanced under an increment in the geometric parameters of the embedded cylinder. Increasing Rayleigh/bioconvection Rayleigh numbers enhances the buoyancy forces that accelerate the velocity field. [ABSTRACT FROM AUTHOR]

This research communicates the thermal assessment of Sutterby nanofluid containing the gyrotactic microorganisms with solutal and Marangoni boundaries. The applications of melting phenomenon and thermal conductivity are also considered. The flow is confined by a stretched cylinder. The prospective of Brownian motion and thermophoresis diffusions are also taken account via Buongiorno nanofluid model. The problem is formulated with help of governing relations and equations which are altered into dimensionless form via appropriate variables. The numerical scheme based on shooting scheme is employed to access the solution. A comparative analysis is performed to verify the approximated solution. The observations reveal that the velocity profile enhanced with the Marangoni number while a declining velocity profile has been observed with Sutterby nanofluid parameter and Darcy resistance parameter. The nanofluid temperature get rise with thermal conductivity parameter and thermal Biot number. An arising profile of nanofluid concentration is observed for concentration conductivity parameter and buoyancy ratio parameter. [ABSTRACT FROM AUTHOR]

Owing to the magnified thermal performances of nanoparticles and essential applications in various industrial and engineering processes like heat exchangers, cooling systems, boilers, MEMS, chemical engineering, laser diode arrays and cool automobile engines, variety of research is presented in this topic. On this end, current investigation deals with the unsteady flow of Williamson nanofluid containing the gyrotactic microorganisms over a rotating cylinder. The additional features like activation energy, chemical reaction and variable thermal conductivity are also composed in the current flow problem. The whole flow model is subjected to the second order slip from which results two slip parameters that effectively control the associated boundary layers. The formulated problem is based on the utilization of governing equations which are converted into dimensionless form with help of appropriate transformation. The self similar solution of constituted equations is followed by using shooting technique. The obtained results are confirmed by comparing already reported investigations with convincible agreement. The graphical analysis for involved parameters is comprehensively presented for both circular cylinder and flat plat as a liming case. The physical aspects of each flow parameter are discussed. The numerical illustration for local Nusselt number, local Sherwood number and motile density number are also presented in tabular form. The results show that temperature ratio parameter and slip constant increase the nanofluid temperature which is more prominent in case of circular cylinder. The concentration and microorganism distributions enhances with unsteady parameter. Moreover, a declining microorganism distribution is observed with mixed convection parameter, Peclet number and bioconvection Lewis number. [ABSTRACT FROM AUTHOR]

This paper investigates the bioconvection in rotating system between two rotating plates immersed in a nanofluid with temperature dependent viscosity and thermal conductivity. The passively controlled model is introduced to characterize the nanoparticle concentration on the upper plate. By means of the similarity transformation, the proposed governing equations are reduced to a class of coupled ODEs with boundary conditions and then the numerical solutions are obtained by the Matlab bvp4c ODE solver. Some important characteristics of velocity, temperature, nanoparticle concentration and density of the motile microorganisms are displayed graphically and discussed in detail. Results show that the viscosity variation parameter has remarkable influence on the local skin friction coefficient and Sherwood number, while local Nusselt number and wall motile microorganisms flux are more sensitive to the thermal conductivity variation parameter. Higher bioconvection Péclet number leads to the aggregation of the motile microorganisms in the middle of the two plates. Moreover, the aggregation of motile microorganisms is weakened by the intense Brownian motion, but improved by the thermophoresis effect. [ABSTRACT FROM AUTHOR]

The present work focuses on the numerical investigations of the existence of oxytactic microorganisms on the bioconvection flow of nano-encapsulated phase change material (NEPCM) inside an annulus. The novel geometry of an annulus contains an inner wavy cylinder and an outer circular cylinder considering a rotational circular velocity of an inner wavy cylinder. The incompressible smoothed particle hydrodynamics (ISPH) method solved the dimensionless form of controlling equations. The novel annulus between the embedded circular cylinder and the outer circular cylinder can be applied in the tube bundles in heat exchangers. Further, rotation of an inner wavy cylinder in a circular cavity can be used in thermal fin's vibration and cooling of the electric devices. The effects of pertinent parameters such as a rotational frequency number ω , bioconvection Rayleigh number Ra b , thermal radiation Rd , Lewis number Le , and Hartmann number Ha on the contours of oxygen concentration ϕ , temperature θ , heat capacity ratio Cr , oxytactic microorganisms N , and velocity field V as well as the average Nusselt & Sherwood numbers Nu ¯ and Sh ¯ are conducted. Increasing ω enhances the maximum of V by 56.6% and lowers Nu ¯. The variations of Ra b are enhanced the contours of N and maximized the velocity field from 0.86 at Ra b = 1 to 8.22 at Ra b = 100 due to the power in bioconvection flow. Increasing Le diminishes the strength of oxygen concentration ϕ and microorganisms N. Increasing Ha from 0 to 50 slows down the velocity field's maximum by 47.2 % and enhances the value of Nu ¯. [ABSTRACT FROM AUTHOR]

[Display omitted] • Here three-dimensional radiative Maxwell nanoparticles is addressed. • Bio-convection is considered. • Non-uniform heat source and sink is inspected for heat transfer phenomenon improvement. • Porous impact and inertial forces are encountered via Darcy-Forchheimer law. The three-dimensional analysis for radiative Maxwell nanoparticles in presence of microorganisms due to rotating frame in numerically addressed numerically. The novel impact of non-uniform heat source and sink is inspected for heat transfer phenomenon improvement. The porous impact and inertial forces are also encountered via Darcy-Forchheimer law. The convective boundary conditions are utilized for the simulated problem. The modified version of Buongiorno nano-model is followed for inspecting the thermophoretic behavior and Brownian movement of nanoparticles. The shooting numerical technique is employed for simulation procedure. The fluctuated pattern of velocity, heat transfer rate, concentration change and microorganism profile is noticed. The results claimed that the presence of inertial parameter declined the velocity but enhanced the nanofluid temperature and concentration profiles. The non-uniform heat source parameters significantly improve the heat transfer rate. The change in rotation parameter reduces the velocity while reverse observations are noted for temperature and concentration profiles. [ABSTRACT FROM AUTHOR]

Velocity profile for (a) parameter M and K (b) Rb and Nr. (c) β m and factor β 1 [Display omitted] • Here Brinkman type micropolar nanoparticles over a stretched surface. • Bio-convection with gyrotactic microorganismss is considered. • Non-uniform heat source and sink is accounted. • Thermo-diffusion aspects of nano-materials are visualized for heat and mass transfer phenomenon. The thermal consequences of the Brinkman type micropolar nanoparticles are inspected theoretically in presence of microorganisms. The impact of non-uniform heat source and sink is also observed. The thermo-diffusion aspects of nano-materials are visualized for heat and mass transfer phenomenon. The appropriate transformations successfully convert the flow problem into dimensionless form. The shooting numerical computations are performed to access the solution. The accuracy of numerical data is predicted via making comparison with already performed continuations. The graphical significances for the desired parameters is addressed with aims for graphs and tables. The findings are summarized with practical applications. The novel outcomes show that velocity of fluid reduces with inclination factor and Brinkman parameter. The nanofluid temperature is enhanced with non-uniform heat source sink parameters and Brinkman parameter. The nanofluid concentration reduces with viscosity constraint. The obtained results presents applications in the era of thermal engineering, energy production, cooling and heat systems, enzymes etc. [ABSTRACT FROM AUTHOR]

A three-dimensional (3-D) investigation of micropolar nanofluid has been presented under the novel impact of nonlinear thermal radiation, activation energy and magnetohydrodynamic features. The induced flow is reflected by a rotating disk which rotates with uniform velocity along z -directions. The fundamental features of Brownian diffusion and thermophoretic assessment is determined by following Buongiorno's nanofluid model. The nanofluid contains gyrotactic microorganisms for which bioconvection pattern is examined for stability assessment. The model flow problem under the certain flow assumptions are retained into the set of dimensionless eqs. A numerical procedure is employed to achieve the solution of such equations. The prime features of parameters against velocity, temperature, concentration and microorganism profiles are graphically examined with justified physical consequences. The numerical computations for wall shear stress, effective local Nusselt number, local Sherwood number and local motile density number are elaborated in terms of numerical data. The simulated theoretical results yield dynamic applications in era of thermal engineering and bio-technology area [ABSTRACT FROM AUTHOR]

The aim of current attempt is to visualize the flow of ('modified') second-grade nanofluid with heat, motile microorganisms and mass transfer rates over stretching surface. The modified second grade fluid is utilized to analyze the rheological behavior. The energy equation is modified with presence of heat absorption and generation effects. In order to stabilize the suspension of nanoparticles, the concept of microorganisms has been introduced. Further present flow analysis is performed with Nield boundary conditions. The formulated equations are first reduced in to dimensionless form by using similarity variables. The approximate solution of these locally similar nonlinear ordinary differential equations is calculated by using shooting method through computational software MATLAB. The calculated results are carefully compared with earlier studies and found an excellent agreement. The ascendancy of interesting parameters like generalized second-grade parameter Brownian motion, thermophoresis effects, Peclet number are examined for multiple values of power law index. It is found that velocity profile declined effectively by buoyancy ratio parameter and bioconvection Rayleigh number. The temperature and concentration profiles enhanced with thermophoretic parameter. It is further observed that motile microorganism profile depressed with Brownian movement parameter and Prandtl number. A prominent demising temperature profile has been noted for shear thickening case as compared to shear thinning. • Modified second-grade nanofluid with motile microorganisms is studied. • Present flow analysis is performed with Nield boundary conditions. • The flow is considered over a stretching surface in two-dimensional channel. • MATLAB software is used to execute the numerical shooting algorithm. • A numerical comparison is also presented for the governing parameters. [ABSTRACT FROM AUTHOR]

On account of fabrication of nano bio-materials applications in various industrial and technological manufacturing systems, bioconvection in nanofluid has become famous in recent years. This investigation is made by adopting bioconvected flow of Oldroyd-B nanofluid over stretched sheet which assumed to be oscillatory. The periodically moving sheet generates the flow. The thermal radiations effects are also encountered in the energy equation. Three independent variables governed by the flow equations are diminished into two independent variables. The series solution for transformed ordinary differential equations is calculated by homotopy analysis method. In present investigation, thermal radiation for linearized Rosseland's assumption is studied in one parametric approach instead of two parametric approaches. Here, the temperature profile does not depend upon Prandtl number and radiation parameter but combination of these two which is termed as effective Prandtl number. Significance of flow parameters on effective local Nusselt number, local Sherwood number and local motile density number is evaluated in tabular form. It is noted that the temperature of nanoparticles effectively enhanced by increasing buoyancy ratio and Rayleigh number. The concentration profile increases with buoyancy ratio and bioconvected Rayleigh number. The higher values of bio-convected Peclet number lead to be decrement of motile microorganism profile. The results presented here can play effective role for enhancement of efficiency of heat transfer devices and microbial fuel cells. • Bioconvected flow of Oldroyd-B nanofluid over stretched sheet is considered. • The periodically moving sheet generates the flow. • The thermal radiations effects are also encountered in the energy equation. • Local Nusselt number, local Sherwood number and local motile density number are evaluated in tabular form. [ABSTRACT FROM AUTHOR]