Stagnation point flows in analytical chemistry and life sciences

Brimmo, Ayoola T.; Qasaimeh, Mohammad A.

doi:10.1039/c7ra11155j

“…Brimmo and Qasaimeh [5] defined stagnation point flow as the scenario where a body of fluid lacks mobility through a given region such that the region has a zero local velocity. Stagnationpoint flow, describing the fluid motion over a continuously stretching surface in presence of electromagnetic fields are significant in many engineering processes with applications in industries such as the metallurgy, polymer processing, glass blowing, glass-fibre production, paper production, plastic films drawing, filaments drawn through a quiescent electrically conducting fluid subject to a magnetic field and the purification of molten metal from non-metallic inclusions.…”

Section: Introductionmentioning

confidence: 99%

Buoyancy-Induced MHD Stagnation Point Flow of Williamson Fluid with Thermal Radiation

Ouru

¹

,

Mutuku

²

,

Oke

³

2020

JERR

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Flow of fluids subjected to thermal radiation has enormous application in polymer processing, glass blowing, cooling of nuclear reactant and harvesting solar energy. This paper considers the MHD stagnation point flow of non-Newtonian pseudoplastic Williamson fluid induced by buoyancy in the presence of thermal radiation. A system of nonlinear partial differential equations suitable to describe the MHD stagnation point flow of Williamson fluid over a stretching sheet is formulated and then transformed using similarity variables to boundary value ordinary differential equations. The graphs depicting the effect of thermal radiation parameter, buoyancy and electromagnetic force on the fluid velocity and temperature of the stagnation point flow are given and the results revealed that increase in buoyancy leads to an increase in the overall velocity of the flow but a decrease in the temperature of the flow.

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“…Implementing the transformations given in Eqn. (10), into the nano-polymer boundary layer Eqns. Stream function is re-defined [49] as:…”

Section: Introductionmentioning

confidence: 99%

Thermal Slip in Oblique Radiative Nano-polymer Gel Transport with Temperature-Dependent Viscosity: Solar Collector Nanomaterial Coating Manufacturing Simulation

Mehmood

¹

,

Tabassum

²

,

Kuharat

³

et al. 2018

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“… With increasing thermophoresis parameter ( Nt ), there is a significant reduction in local micro-organism reduced density numbers ( Nnr ) and this is magnified with increasing Lewis numbers. The computational results achieved with the finite difference method (FDM) are numerically stable and accurate and this technique has been found to be very appropriate for nonlinear stagnation thin film nano-bio coating flow simulations of relevance to achieving good film growth in bio-inspired nanotechnological manufacturing 60 , 61 . …”

Section: Discussionmentioning

confidence: 99%

“…The computational results achieved with the finite difference method (FDM) are numerically stable and accurate and this technique has been found to be very appropriate for nonlinear stagnation thin film nano-bio coating flow simulations of relevance to achieving good film growth in bio-inspired nanotechnological manufacturing 60 , 61 .…”

Section: Discussionmentioning

confidence: 99%

Numerical study of nano-biofilm stagnation flow from a nonlinear stretching/shrinking surface with variable nanofluid and bioconvection transport properties

Alsenafi

¹

,

Bég

²

,

Ferdows

³

et al. 2021

Sci Rep

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A mathematical model is developed for stagnation point flow toward a stretching or shrinking sheet of liquid nano-biofilm containing spherical nano-particles and bioconvecting gyrotactic micro-organisms. Variable transport properties of the liquid (viscosity, thermal conductivity, nano-particle species diffusivity) and micro-organisms (species diffusivity) are considered. Buongiorno’s two-component nanoscale model is deployed and spherical nanoparticles in a dilute nanofluid considered. Using a similarity transformation, the nonlinear systems of partial differential equations is converted into nonlinear ordinary differential equations. These resulting equations are solved numerically using a central space finite difference method in the CodeBlocks Fortran platform. Graphical plots for the distribution of reduced skin friction coefficient, reduced Nusselt number, reduced Sherwood number and the reduced local density of the motile microorganisms as well as the velocity, temperature, nanoparticle volume fraction and the density of motile microorganisms are presented for the influence of wall velocity power-law index (m), viscosity parameter $$({c}_{2})$$ ( c 2 ) , thermal conductivity parameter (c4), nano-particle mass diffusivity (c6), micro-organism species diffusivity (c8), thermophoresis parameter $$(Nt)$$ ( N t ) , Brownian motion parameter $$(Nb)$$ ( N b ) , Lewis number $$(Le)$$ ( L e ) , bioconvection Schmidt number $$(Sc)$$ ( S c ) , bioconvection constant (σ) and bioconvection Péclet number $$(Pe)$$ ( P e ) . Validation of the solutions via comparison related to previous simpler models is included. Further verification of the general model is conducted with the Adomian decomposition method (ADM). Extensive interpretation of the physics is included. Skin friction is elevated with viscosity parameter ($${\mathrm{c}}_{2})$$ c 2 ) whereas it is suppressed with greater Lewis number and thermophoresis parameter. Temperatures are elevated with increasing thermal conductivity parameter ($${\mathrm{c}}_{4})$$ c 4 ) whereas Nusselt numbers are reduced. Nano-particle volume fraction (concentration) is enhanced with increasing nano-particle mass diffusivity parameter ($${c}_{6}$$ c 6 ) whereas it is markedly reduced with greater Lewis number (Le) and Brownian motion parameter (Nb). With increasing stretching/shrinking velocity power-law exponent ($$m),$$ m ) , skin friction is decreased whereas Nusselt number and Sherwood number are both elevated. Motile microorganism density is boosted strongly with increasing micro-organism diffusivity parameter ($${\mathrm{c}}_{8}$$ c 8 ) and Brownian motion parameter (Nb) but reduced considerably with greater bioconvection Schmidt number (Sc) and bioconvection Péclet number (Pe). The simulations find applications in deposition processes in nano-bio-coating manufacturing processes.

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Stagnation point flows in analytical chemistry and life sciences

Abstract: Isolated microfluidic stagnation points – formed within microfluidic interfaces – have come a long way as a tool for characterizing materials, manipulating micro particles, and generating confined flows and localized chemistries.

Cited by 39 publications

References 283 publications

Buoyancy-Induced MHD Stagnation Point Flow of Williamson Fluid with Thermal Radiation

Buoyancy-Induced MHD Stagnation Point Flow of Williamson Fluid with Thermal Radiation

Thermal Slip in Oblique Radiative Nano-polymer Gel Transport with Temperature-Dependent Viscosity: Solar Collector Nanomaterial Coating Manufacturing Simulation

Numerical study of nano-biofilm stagnation flow from a nonlinear stretching/shrinking surface with variable nanofluid and bioconvection transport properties

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