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Biomathematical model for gyrotactic free-forced bioconvection with oxygen diffusion in near-wall transport within a porous medium fuel cell

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International Journal of Biomathematics 2020年第4期13卷 141-165页

作者： Nayema Islam Nima M.Ferdows o.anwar beg S.Kuharatt Faris Alzahranit Research Group of Fluid Flow Modeling and Simulation Department of Applied Mathematics University of Dhaka Dhaka-100Bangladesh Multi-Physical Engineering Sciences Group Aeronautical/Mechanical Engineering School of Science Engineering and Environment(SEE)University of SalfordManchesterUK

Bioconvection has shown significant promise for environmentally friendly,sustainable“green”fuel cell *** improved design of such systems requires continuous refinements in biomatheatical modeling in conjunction with laboratory and *** by exploring deeper the near-wall transport phenomena involved inbio-inspired fuel cells,in the present paper,we examine analytically and numericallythe combined free-forced convective steady boundary layer flow from a solid verticalflat plate embedded in a Darcian porous medium containing gyrotactic *** is one of the many taxes exhibited in biological microscale transport,andother examples include magneto-taxis,photo-taxis,chemotaxis and geo-taxis (reflecting the response of microorganisms to magnetic field,light,chemical concentration orgravity,respectively). The bioconvection fuel cell also contains difusing oxygen specicswhich mimics the cathodic behavior in a proton exchange membrane(PEM) *** wall is maintained at isosolutal (constant oxygen volume fraction and motilemicroorganism density) and iso-thermal conditions. Wall values of these quantities aresustained at higher values than the ambient temperature and concentration of oxygenand biological microorganism *** transformations are applied to renderthe governing partial differential equations for mass,momentum,energy,oxygen speciesand microorganism species density into a system of ordinary differential equations. Theemerging eight order nonlinear coupled,ordinary differential boundary value problemfeatures several important dimensionless control parameters,namely Lewis number(Le),buoyancy ratio paraneter i.e. ratio of oxygen species buoyancy force to thermal buoy-ancy force(Nr), bioconvection Rayleigh number(Rb), bioconvection Lewis number(Lb),bioconvection Peclet number(Pe) and the mixed convection parameter(e) spanning theentire range of free and forced convection. The transformed nonlinear sys

关键词： Bioconvection gyrotactic microorganisms oxygen diffusion buoyancy Lewis number boundary layers fuel cells numerical solution Nusselt nurnber Sherwood number

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Numerical simulation of self-similar thermal convection from a spinning cone in anisotropic porous medium

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Journal of Hydrodynamics 2016年第2期28卷 184-194页

作者： o. anwar beg M. J. UDDIN T. beg R. Reddy GoRLA Spray Research Group Petroleum and Gas Engineering Division Room G77 Newton Building School of Computing Science and Engineering (CSE) University of Salford M54WT UK Department of Mathematics American International University-Bangladesh Dhaka Bangladesh Engineering Mechanics Associates Dickenson Road Manchester M 16 England UK Department Mechanical Engineering Cleveland State University Cleveland Ohio USA

Self-similar steady natural convection thermal boundary layer flow from a rotating vertical cone to anisotropic Darcian porous medium is investigated theoretically and numerically. The transformed non-dimensional two-point boundary value problem is reduced to a system of coupled, highly nonlinear ordinary differential equations, which are solved subject to robust surface and free stream boundary conditions with the MAPLE 17 numerical quadrature software. Validation with earlier non-rotating studies is included, and also further verification of rotating solutions is achieved with a variational finite element method （FEM）. The rotational （spin） parameter emerges as an inverse function of the Grashof number. The influence of this parameter, primary Darey number, secondary Darcy number and Prandtl number on tangential velocity and swirl velocity, temperature and heat transfer rate are studied in detail. It is found that the dimensionless tangential velocity increases whilst the dimensionless swirl velocity and temperature decrease with the swirl Darcy number, tangential Darcy number and the rotational parameters. The model finds applications in chemical engineering filtration processing, liquid coating and spinning cone distillation columns.

关键词： self-similarity spinning cone finite element method (FEM) anisotropic porous medium heat transfer MAPLE FEM

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DTM Simulation of Peristaltic Viscoelastic Biofluid Flow in Asymmetric Porous Media： A Digestive Transport Model

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Journal of Bionic Engineering 2015年第4期12卷 643-655页

作者： Dharmendra Tripathi osman anwar beg Praveen Kumar Gupta Ganjam Radhakrishnamacharya Jagannath Mazumdar Department of Mechanical Engineering Manipal University Jaipur Jaipur 303007 India Gort Engovation-Bio-Propulsion Research Gabriel's Wing House Bradford BD6 1FA UK Department of Mathematics National Institute of Technology Silchar Silchar 788010 India Department of Mathematics National Institute of Technology Warangal 506004 India School of Electrical & Electronic Engineering The University of Adelaide Adelaide SA 5005 Australia

A biofluid dynamics mathematical model is developed to study peristaltic flow of non-Newtonian physiological liquid in a two-dimensional asymmetric channel containing porous media as a simulation of obstructed digestive （intestinal） transport. The fractional oldroyd-B viscoelastic rheological model is utilized. The biophysical flow regime is constructed as a wave-like motion and porous medium is simulated with a modified Darcy-Brinkman model. This model is aimed at describing the diges- tive transport in intestinal tract containing deposits which induce impedance. A low Reynolds number approximation is em- ployed to eliminate inertial effects and the wavelength to diameter ratio is assumed to be large. The differential transform method （DTM）, a semi-computational technique is employed to obtain approximate analytical solutions to the boundary value problem. The influences of fractional （rheological material） parameters, relaxation time, retardation time, amplitude of the wave, and permeability parameter on peristaltic flow characteristics such as volumetric flow rate, pressure difference and wall friction force are computed. The present model is relevant to flow in diseased intestines.

关键词： peristaltic transport fractional oldroyd-B model porous medium differential transform method asymmetricchannel obstructed digestive flow

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Transient analysis of Casson fluid thermo-convection from a vertical cylinder embedded in a porous medium: Entropy generation and thermal energy transfer visualization

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Journal of Central South University 2019年第5期26卷 1342-1361页

作者： JANARDHANA REDDY G BHASKERREDDY Kethireddy MAHESH Kumar anwar beg o Department of Mathematics Central University of KarnatakaKalaburagi585367India Fluid Mechanics Aeronautical and Mechanical Engineering DepartmentSchool of ComputingScience and EngineeringUniversity of SalfordManchester M54WTUK

Thermal transport in porous media has stimulated substantial interest in engineering sciences due to increasing applications in filtration systems,porous bearings,porous layer insulation,biomechanics,geomechanics *** by such applications,in this article,a numerical study of entropy generation impacts on the heat and momentum transfer in time-dependent laminar incompressible boundary layer flow of a Casson viscoplastic fluid over a uniformly heated vertical cylinder embedded in a porous medium is ***’s law is used to simulate bulk drag effects at low Reynolds number for an isotropic,homogenous porous *** line visualization is also *** mathematical model is derived and normalized using appropriate transformation *** resulting non-linear time-dependent coupled governing equations with associated boundary conditions are solved via an implicit finite difference method which is efficient and unconditionally *** outcomes show that entropy generation and Bejan number are both elevated with increasing values of Darcy number,Casson fluid parameter,group parameter and Grashof *** analyze the heat transfer process in a two-dimensional domain,plotting heat lines provides an excellent approach in addition to streamlines and *** is remarked that as the Darcy number increases,the deviations of heat lines from the hot wall are reduced.

关键词： vertical cylinder entropy generation Casson fluid finite difference method heat function porous medium

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Adomian decomposition method simulation of von Kármán swrling bioconvection nanofluid flow

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Journal of Central South University 2019年第10期26卷 2797-2813页

作者： M D SHAMSHUDDIN S R MISHRA o.anwar beg A KADIR Department of Mathematics Vaagdevi College of EngineeringWarangalTelanganaIndia Department of Mathematics Siksha'O’Anusandhan Deemed to be UniversityKhandagiriBhubaneswarOdishaIndia Department of Aeronautical and Mechanical Engineering University of SalfordManchesterEnglandUK

The study reveals analytically on the 3-dimensional viscous time-dependent gyrotactic bioconvection in swirling nanofluid flow past from a rotating *** is known that the deformation of the disk is along the radial *** addition to that Stefan blowing is *** Buongiorno nanofluid model is taken care of assuming the fluid to be dilute and we find Brownian motion and thermophoresis have dominant role on nanoscale *** primitive mass conservation equation,radial,tangential and axial momentum,heat,nano-particle concentration and micro-organism density function are developed in a cylindrical polar coordinate system with appropriate wall(disk surface)and free stream boundary *** highly nonlinear,strongly coupled system of unsteady partial differential equations is normalized with the classical von Kármán and other transformations to render the boundary value problem into an ordinary differential *** emerging 11th order system features an extensive range of dimensionless flow parameters,i.e.,disk stretching rate,Brownian motion,thermophoresis,bioconvection Lewis number,unsteadiness parameter,ordinary Lewis number,Prandtl number,mass convective Biot number,Péclet number and Stefan blowing *** of the system are obtained with developed semi-analytical technique,i.e.,Adomian decomposition *** of the said problem is also conducted with earlier literature computed by Runge-Kutta shooting technique.

关键词： nanofluids bioconvection rotating disk bioreactors von Kármán swirling flow Stefan blowing Adomian decomposition method(ADM)

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Numerical Modeling of Non-Similar Mixed Convection Heat Transfer over a Stretching Surface with Slip Conditions

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World Journal of Mechanics 2015年第6期5卷 117-128页

作者： A. Subba Rao V. R. Prasad N. Nagendra K. V. N. Murthy N. Bhaskar Reddy o. anwar beg Department of Mathematics Madanapalle Institute of Technology and Science Madanapalle India Department of Mathematics Sri Venkateswara University Tirupathi India Gort Engovation Research (Propulsion and Biomechanics) Bradford UK

In this paper, the heat transfer effect on the steady boundary layer flow of a Casson fluid past a stretching surface in the presence of slip conditions was analyzed. The stretching surface is maintained at a constant temperature. The boundary layer conservation equations, which are parabolic in nature, are normalized into non-similar form and then solved numerically with the well-tested, efficient, implicit, stable Keller-box finite difference scheme. The resulting equations are solved numerically by using the Kellerbox finite-difference method, and the expressions for velocity and temperature are obtained. They satisfy all imposed initial and boundary conditions and reduce to some well-known solutions for non-Newtonian fluids. Numerical results for velocity, temperature, skin friction and Nusselt number are shown in various graphs and discussed for embedded flow parameters. It is found that both velocity and temperature decrease with an increase of the Casson fluid parameter.

关键词： Stretching Surface Non-Newtonian Fluid Slip Condition Keller-Box Numerical Method Heat Transfer Skin Friction Coefficient

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Comparison of Shisha Smoking Behavior among Medical and Pharmacy Students

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Journal of Behavioral and Brain Science 2016年第7期6卷 269-279页

作者： Ashok Kumar Salman Baig Sana Ansari Nadeem Rizvi Huma Sharif anwar Ejaz beg Ammara Rauf Faraz Ahmed Baig Ammara Abdul Majeed Ziauddin Hospital Karachi Pakistan Sindh Medical College Karachi Pakistan

Background: Health care workers are respected in every society and have a strong influence on the behaviour of the community. In order to reduce the shisha dependence in the Pakistani population, it is necessary to evaluate the perspective of future doctors and pharmacists regarding this addiction as they become role models for the future generations. objective: The aim is to compare the knowledge, attitudes, and practices of shisha use among medical students and pharmacy students in order to assess their support in the anti-shisha campaigns of Pakistan. Methodology: Cross sectional study was performed in four major medical universities of Karachi, Pakistan through a modification of the WHo global health survey questionnaire. Result: 398 medical students and 470 pharmacy students were included in the study which showed that currently 9.6% pharmacy students and 4.8% medical students used shisha daily (p = 0.000). Pharmacy students started shisha use in less than 15 years of age while this number was 29.5% among medical students (P = 0.000). Moreover, 44.6% pharmacy students and 50% medical students were not planning to quit this addiction within the next six months. 14% of pharmacy students and 20.4% in medical students (P = 0.002) were unaware that passive smoking caused lung cancer, while 23.4% pharmacy students and 33.5% medical students rejected it as cause of heart diseases (p = 0.006). Conclusion: A significant number of medical and pharmacy students were unaware about some of the serious consequences of shisha smoking. Therefore, both groups of students need to be educated about the health hazards of shisha use, in order to control this growing menace.

关键词： Shisha Smoking Tobacco Students

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