scholarly journals Influence of Chemically Reacting Ferromagnetic Carreau Nanofluid over a Stretched Sheet with Magnetic Dipole and Viscous Dissipation

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
R. M. Akram Muntazir ◽  
M. Mushtaq ◽  
S. Shahzadi ◽  
K. Jabeen
Keyword(s):  
Boundary Layer ◽  
Magnetic Dipole ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Nusselt Numbers ◽  
Similarity Transformations ◽  
Highly Nonlinear ◽  
Shear Thickening Fluids ◽  
Carreau Nanofluid ◽  
Chemically Reacting

Due to potential implications, boundary layer analysis of chemically reacting Carreau nanofluid has been carried out to examine flow properties of ferromagnetic fluid over a stretched sheet in the presence of magnetic dipole, for shear thinning and shear thickening fluids. Furthermore, the transportation of heat under thermal radiation, heat generation, the Brownian, and thermophoresis aspects has been evaluated. The dimensionless form of highly nonlinear coupled partial differential equations is obtained using suitable similarity transformations and then solved numerically by well-known bvp 4 c technique via MATLAB based on the shooting method. The outcomes of physical quantities are presented through graphs and numerical benchmarks. Moreover, outcomes for skin fraction, Sherwood and Nusselt numbers for velocity, concentration, and temperature are also estimated in this study. The present study reveals that the concentration and thermal boundary layer thicknesses were higher for shear thinning n < 1 fluid when compared with shear thickening n > 1 fluids, but reverse effects are to be observed for momentum boundary layer thickness.

Spread of a non-Newtonian liquid jet over a horizontal plate

2008 ◽  
Vol 613 ◽  
pp. 411-443 ◽  
Author(s):  
JIANGANG ZHAO ◽  
ROGER E. KHAYAT
Keyword(s):  
Boundary Layer ◽  
Power Law ◽  
Hydraulic Jump ◽  
Shear Thickening ◽  
Flow Region ◽  
Shear Thinning ◽  
Similarity Solutions ◽  
Viscous Boundary Layer ◽  
Power Law Fluids ◽  
Shear Thickening Fluids

The flow of an impinging non-Newtonian jet onto a solid flat plate is examined theoretically in this study. Similarity solutions are sought for both shear-thinning and shear-thickening fluids of the power-law type. The jet is assumed to spread out in a thin layer bounded by a hydraulic jump. In addition to the stagnation-flow region, the flow domain is divided into three main regions: a developing boundary layer, fully viscous boundary layer and hydraulic jump. The anomalous behaviour of power-law fluids at small shear rate is remedied by seeking a two-layer solution in each domain. Such anomalies include the singularity of viscosity for shear-thinning fluids, and the vanishing of viscosity as well the overshoot in velocity for shear-thickening fluids. Although the rate of shear-thinning appears to affect significantly the film profile and velocity, only the overall viscosity influences the position of the hydraulic jump.

Stability of Shear-Thickening Liquids Between Rotating Cylinders

2010 ◽  
Author(s):  
Nariman Ashrafi ◽  
Habib Karimi Haghighi
Keyword(s):  
Couette Flow ◽  
Dynamical Behavior ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Taylor Vortex ◽  
Shear Dependent Viscosity ◽  
Shear Thinning Fluids ◽  
Shear Thickening Fluids ◽  
The Stability ◽  
Dependent Viscosity

The effects of nonlinearities on the stability are explored for shear thickening fluids in the narrow-gap limit of the Taylor-Couette flow. It is assumed that shear-thickening fluids behave exactly as opposite of shear thinning ones. A dynamical system is obtained from the conservation of mass and momentum equations which include nonlinear terms in velocity components due to the shear-dependent viscosity. It is found that the critical Taylor number, corresponding to the loss of stability of Couette flow becomes higher as the shear-thickening effects increases. Similar to the shear thinning case, the Taylor vortex structure emerges in the shear thickening flow, however they quickly disappear thus bringing the flow back to the purely azimuthal flow. Naturally, one expects shear thickening fluids to result in inverse dynamical behavior of shear thinning fluids. This study proves that this is not the case for every point on the bifurcation diagram.

Drops of power-law fluids falling on a coated vertical fibre

2014 ◽  
Vol 751 ◽  
pp. 184-215
Author(s):  
Liyan Yu ◽  
John Hinch
Keyword(s):  
Solitary Waves ◽  
Power Law ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Bond Number ◽  
Power Law Fluid ◽  
Shear Thinning Fluids ◽  
Power Law Fluids ◽  
Shear Thickening Fluids ◽  
The Stability

AbstractWe study the solitary wave solutions in a thin film of a power-law fluid coating a vertical fibre. Different behaviours are observed for shear-thickening and shear-thinning fluids. For shear-thickening fluids, the solitary waves are larger and faster when the reduced Bond number is smaller. For shear-thinning fluids, two branches of solutions exist for a certain range of the Bond number, where the solitary waves are larger and faster on one and smaller and slower on the other as the Bond number decreases. We carry out an asymptotic analysis for the large and fast-travelling solitary waves to explain how their speeds and amplitudes change with the Bond number. The analysis is then extended to examine the stability of the two branches of solutions for the shear-thinning fluids.

scholarly journals Thermophoresis and Brownian Effect for Chemically Reacting Magneto-Hydrodynamic Nanofluid Flow across an Exponentially Stretching Sheet

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 143
Author(s):  
Mubashar Arshad ◽  
Azad Hussain ◽  
Ali Hassan ◽  
Qusain Haider ◽  
Anwar Hassan Ibrahim ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Chemical Reaction ◽  
Chemical Change ◽  
Fluid Motion ◽  
Fluid Temperature ◽  
Similarity Transformations ◽  
Chemically Reacting ◽  
First Order Chemical Reaction ◽  
Buongiorno Model

This comparative research investigates the influence of a flexible magnetic flux and a chemical change on the freely fluid motion of a (MHD) magneto hydrodynamic boundary layer incompressible nanofluid across an exponentially expanding sheet. Water and ethanol are used for this analysis. The temperature transmission improvement of fluids is described using the Buongiorno model, which includes Brownian movement and thermophoretic distribution. The nonlinear partial differential equalities governing the boundary layer were changed to a set of standard nonlinear differential equalities utilizing certain appropriate similarity transformations. The bvp4c algorithm is then used to tackle the transformed equations numerically. Fluid motion is slowed by the magnetic field, but it is sped up by thermal and mass buoyancy forces and thermophoretic distribution increases non-dimensional fluid temperature resulting in higher temperature and thicker boundary layers. Temperature and concentration, on the other hand, have the same trend in terms of the concentration exponent, Brownian motion constraint, and chemical reaction constraint. Furthermore, The occurrence of a magnetic field, which is aided by thermal and mass buoyancies, assists in the enhancement of heat transmission and wall shear stress, whereas a smaller concentration boundary layer is produced by a first-order chemical reaction and a lower Schmidt number.

Shear-Thickening Flow Between Coaxial Cylinders

2011 ◽  
Author(s):  
Nariman Ashrafi ◽  
Habib Karimi Haghighi
Keyword(s):  
Couette Flow ◽  
Dynamical Behavior ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Taylor Vortex ◽  
Shear Dependent Viscosity ◽  
Shear Thinning Fluids ◽  
Shear Thickening Fluids ◽  
The Stability ◽  
Dependent Viscosity

The effects of nonlinearities on the stability are explored for shear thickening fluids in the narrow-gap limit of the Taylor-Couette flow. A dynamical system is obtained from the conservation of mass and momentum equations which include nonlinear terms in velocity components due to the shear-dependent viscosity. It is found that the critical Taylor number, corresponding to the loss of stability of Couette flow becomes higher as the shear-thickening effects increases. Similar to the shear thinning case, the Taylor vortex structure emerges in the shear thickening flow; however they quickly disappear thus bringing the flow back to the purely azimuthal flow. Naturally, one expects shear thickening fluids to result in inverse dynamical behavior of shear thinning fluids. This study proves that this is not the case for every point on the bifurcation diagram.

First instability of the flow of shear-thinning and shear-thickening fluids past a circular cylinder

2012 ◽  
Vol 701 ◽  
pp. 201-227 ◽  
Author(s):  
Iman Lashgari ◽  
Jan O. Pralits ◽  
Flavio Giannetti ◽  
Luca Brandt
Keyword(s):  
Circular Cylinder ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Base Flow ◽  
Rheological Parameters ◽  
Recirculation Bubble ◽  
The Core ◽  
Shear Dependent Viscosity ◽  
Shear Thickening Fluids ◽  
Dependent Viscosity

AbstractThe first bifurcation and the instability mechanisms of shear-thinning and shear-thickening fluids flowing past a circular cylinder are studied using linear theory and numerical simulations. Structural sensitivity analysis based on the idea of a ‘wavemaker’ is performed to identify the core of the instability. The shear-dependent viscosity is modelled by the Carreau model where the rheological parameters, i.e. the power-index and the material time constant, are chosen in the range $0. 4\leq n\leq 1. 75$ and $0. 1\leq \lambda \leq 100$. We show how shear-thinning/shear-thickening effects destabilize/stabilize the flow dramatically when scaling the problem with the reference zero-shear-rate viscosity. These variations are explained by modifications of the steady base flow due to the shear-dependent viscosity; the instability mechanisms are only slightly changed. The characteristics of the base flow, drag coefficient and size of recirculation bubble are presented to assess shear-thinning effects. We demonstrate that at critical conditions the local Reynolds number in the core of the instability is around 50 as for Newtonian fluids. The perturbation kinetic energy budget is also considered to examine the physical mechanism of the instability.

scholarly journals Convective Hydromagentic Slip Flow with Variable Properties Due to a Porous Rotating Disk

2010 ◽  
Vol 15 ◽  
pp. 55 ◽  
Author(s):  
Mohammad M. Rahman
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Slip Flow ◽  
Rotating Disk ◽  
Heat Transfer Characteristics ◽  
Temperature Dependent ◽  
Transfer Characteristics ◽  
Similarity Transformations ◽  
Flow And Heat Transfer ◽  
Highly Nonlinear

In this paper we investigate convective heat transfer characteristics of steady hydromagnetic slip flow over a porous rotating disk taken into account the temperature dependent density, viscosity and thermal conductivity  in the presence of  Hall current, viscous dissipation and Joule heating. Using von-Karman similarity transformations we reduce the governing equations for flow and heat transfer into a system of ordinary differential equations which are highly nonlinear and coupled. The resulting nondimensional equations are solved numerically by applying Nachtsheim-Swigert iteration technique. The results show that when modeling a thermal boundary layer, with temperature dependent fluid properties, consideration of Prandtl number as constant within the boundary layer, produces unrealistic results.   therefore  Therefore it must be treated as variable throughout the boundary layer. Results also show that the slip factor significantly controls the flow and heat transfer characteristics.  

Power-Law Fluid Flow Passing Two Square Cylinders in Tandem Arrangement

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Izadpanah Ehsan ◽  
Sefid Mohammad ◽  
Nazari Mohammad Reza ◽  
Jafarizade Ali ◽  
Ebrahim Sharifi Tashnizi
Keyword(s):  
Reynolds Number ◽  
Power Law ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Newtonian Fluids ◽  
Power Law Fluid ◽  
Tandem Arrangement ◽  
Square Cylinders ◽  
Shear Thickening Fluids ◽  
Power Law Index

Two-dimensional laminar flow of a power-law fluid passing two square cylinders in a tandem arrangement is numerically investigated in the ranges of 1< Re< 200 and 1 ≤ G ≤ 9. The fluid viscosity power-law index lies in the range 0.5 ≤ n ≤ 1.8, which covers shear-thinning, Newtonian and shear-thickening fluids. A finite volume code based on the SIMPLEC algorithm with nonstaggered grid is used. In order to discretize the convective and diffusive terms, the third order QUICK and the second-order central difference scheme are used, respectively. The influence of the power-law index, Reynolds number and gap ratio on the drag coefficient, Strouhal number and streamlines are investigated, and the results are compared with other studies in the literature to validate the methodology. The effect of the time integration scheme on accuracy and computational time is also analyzed. In the ranges of Reynolds number and power-law index studied here, vortex shedding is known to occur for square cylinders in tandem. This study represents the first systematic investigation of this phenomenon for non-Newtonian fluids in the open literature. In comparison to Newtonian fluids, it is found that the onset of leading edge separation occurs at lower Reynolds number for shear-thinning fluids and is delayed to larger values for shear-thickening fluids.

Formation of Boundary Layer in the Flow of Shear-Dependent-Viscosity Fluids Between Parallel Plates

2017 ◽  
Author(s):  
Nariman Ashrafi ◽  
Ali Sadeghi ◽  
Mehdi Shafahi
Keyword(s):  
Boundary Layer ◽  
Flow Behavior ◽  
Vertical Wall ◽  
Shear Thickening ◽  
Finite Volume Scheme ◽  
Parallel Plates ◽  
Flow Behavior Index ◽  
Shear Dependent Viscosity ◽  
Shear Thickening Fluids ◽  
Dependent Viscosity

Formation of the boundary layer in the laminar flow of Herschel–Bulkley fluid between parallel plates is taken into consideration. In particular, the study is focused on the flow of the shear thinning and shear thickening fluids past a partial vertical wall in between the plates. Upon numerically solving the continuity and momentum equations the flow is analyzed throughout the domain using a finite volume scheme. The shear stress at the wall together with velocity distribution are evaluated and compared with experimental results for several values of Herschel-Bulkley coefficients for fluidity and flow behavior index.

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