Study of heat transfer in a rotating weakly electrically conducting Newtonian fluid: Primary and Kpers-Lortz regimes
subject: Heat transfer; Kpers - Lortz instability; Magnetic field; Newtonian fluids; Rotating RayleighBard convection
description: In this paper, we study the primary and secondary (Kpers-Lortz) instabilities of rotating RayleighBard convection for a weakly electrically conducting Newtonian fluid with idealistic boundaries. The critical Rayleigh number is obtained for each instability. Fourth-order and ninth-order Lorenz model are derived using the truncated Fourier-Galerkin expansion and the onset of primary and secondary instabilities is studied. Using a non-linear analysis, we derive the expression for the Nusselt number for both primary and secondary instabilities. The analysis reveals that the heat transfer in the case of primary instability is an over-prediction when compared with that of the secondary instability. An increase in the strength of the magnetic field is to delay the onset of primary and secondary instabilities and decrease the heat transfer. These insights advance the understanding of magnetohydrodynamic stability in rotating convective systems and have implications for geophysical and astrophysical fluid dynamics. 2025 Elsevier Masson SAS
creator: Reddy, B. Sirisha; Pranesh, S.; Siddheshwar, P.G.
source: European Journal of Mechanics, B/Fluids;Volume;113;Issue;;Article No.;204283;
publisher: Elsevier Ltd
date: 01-01-2025
rights: Restricted Access; Hardcopy may be available in the library
relation: ISSN: 9977546; CODEN: EJBFE
format: online
language: English
type: Article
coverage: Reddy B.S., Centre for Mathematical Needs, Department of Mathematics, Christ University, Bengaluru 560029, India; Pranesh S., Centre for Mathematical Needs, Department of Mathematics, Christ University, Bengaluru 560029, India; Siddheshwar P.G., Centre for Mathematical Needs, Department of Mathematics, Christ University, Bengaluru 560029, India

Study of hybrid nanofluid flow in a stationary cone-disk system with temperature-dependent fluid properties
subject: 76D05; 76R05; 80A20; 82D80; cone-disk system; hybrid nanofluid; laminar flow; Nusselt number; O267; O357; variable fluid property
description: Cone-disk systems find frequent use such as conical diffusers, medical devices, various rheometric, and viscosimetry applications. In this study, we investigate the three-dimensional flow of a water-based Ag-MgO hybrid nanofluid in a static cone-disk system while considering temperature-dependent fluid properties. How the variable fluid properties affect the dynamics and heat transfer features is studied by Reynoldss linearized model for variable viscosity and Chiams model for variable thermal conductivity. The single-phase nanofluid model is utilized to describe convective heat transfer in hybrid nanofluids, incorporating the experimental data. This model is developed as a coupled system of convective-diffusion equations, encompassing the conservation of momentum and the conservation of thermal energy, in conjunction with an incompressibility condition. A self-similar model is developed by the Lie-group scaling transformations, and the subsequent self-similar equations are then solved numerically. The influence of variable fluid parameters on both swirling and non-swirling flow cases is analyzed. Additionally, the Nusselt number for the disk surface is calculated. It is found that an increase in the temperature-dependent viscosity parameter enhances heat transfer characteristics in the static cone-disk system, while the thermal conductivity parameter has the opposite effect. The Author(s) 2024.
creator: John A.S.; Mahanthesh B.; Lorenzini G.
source: Applied Mathematics and Mechanics (English Edition), Vol-45, No. 4, pp. 677-694.
publisher: Springer Science and Business Media B.V.
date: 2024-01-01
rights: All Open Access; Hybrid Gold Open Access
relation: ISSN: 2534827; CODEN: AMMEE
format: Online
language: English
type: Article
coverage: John A.S., Center for Mathematical Needs, Department of Mathematics, CHRIST (Deemed to be University), Karnataka, Bengaluru, 560029, India; Mahanthesh B., Center for Mathematical Needs, Department of Mathematics, CHRIST (Deemed to be University), Karnataka, Bengaluru, 560029, India, School of Mathematical and Statistical Sciences, The University of Texas Rio Grande Valley, Edinburg, 78539, TX, United States; Lorenzini G., Department of Engineering and Architecture, University of Parma, Parma, 43124, Italy

Study of Influence of Combustion on DarcyBard Convection with Inherent Local Thermal Non-equilibrium Between Phases
subject: Chebyshev spectral method; Chemical reaction; Combustion; Energy method; FrankKamenetskii number
description: This work deals with a DarcyBard convection problem in the presence of combustion and with local thermal non-equilibrium between the fluid and the solid phases. The effects of combustion and local thermal non-equilibrium on the onset of convection is studied in the linear and nonlinear regimes. Unlike all reported local thermal non-equilibrium problems reported so far, the present problem has a unique situation of having thermal non-equilibrium not only in the perturbed state but also in the basic state. Further, we observe that local thermal non-equilibrium does not, under any circumstance, lead to local thermal equilibrium except in an approximate sense when the combustion is quite weak. The effect of combustion is to advance the onset of convection compared to that in its absence. The effect of local thermal non-equilibrium is to reinforce the effect of combustion. In the presence of both these effects, sub-critical instability exists. The results are obtained numerically and have implication in practical porous medium convection problems. 2022, The Author(s), under exclusive licence to Springer Nature B.V.
creator: Nandal R.; Siddheshwar P.G.; Neela D.
source: Transport in Porous Media, Vol-146, No. 3, pp. 741-769.
publisher: Springer Science and Business Media B.V.
date: 2023-01-01
rights: Restricted Access
relation: ISSN: 1693913; CODEN: TPMEE
format: Online
language: English
type: Article
coverage: Nandal R., Department of Mathematics, Centre for Mathematical Needs, Christ (Deemed to be University), Bengaluru, 560029, India; Siddheshwar P.G., Department of Mathematics, Centre for Mathematical Needs, Christ (Deemed to be University), Bengaluru, 560029, India; Neela D., Department of Mathematics, NIT Warangal, Telangana, Hanamkonda, 506004, India

Study of internal heat source generated natural convection with sinusoidal and non-sinusoidal time-periodic vertical oscillations
subject: Brinkman-Bard convection; GinzburgLandau equation; Gravity modulation; Heat transport; Maclaurin series solution; Sawtooth; Sinusoidal; Square wave forms; Triangular
description: This study explores the effect of gravity modulation on natural convection induced by a uniform internal heat source within a fluid-saturated porous medium, a topic of growing relevance in advanced thermal management applications. Four distinct gravity waveforms, square, sinusoidal, triangular, and sawtooth, are examined under three boundary condition combinations: Rigid-Adiabatic-Rigid-Isothermal (RARI), Rigid-Adiabatic-Free-Isothermal (RAFI), and Free-Adiabatic-Free-Isothermal (FAFI). A novel analytical framework is developed by integrating a Maclaurin series expansion with a minimal FourierGalerkin approach to derive a generalized Lorenz model. Linear stability analysis, via a modified Venezian method, to determine the critical internal Rayleigh number and its correction due to modulation. A weakly nonlinear analysis based on the GinzburgLandau equation also provides closed-form expressions for the mean Nusselt number, capturing heat transfer characteristics. The findings demonstrate that square wave modulation most effectively enhances heat transport, followed by sinusoidal, triangular, and sawtooth forms. The influence of key physical parameters reveals that increasing porous parameter (?2) and Brinkman number (?) suppress heat transfer, as do higher Prandtl numbers (Pr) and modulation frequencies (?). FAFI yields the highest heat transfer among the boundary types, while RARI performs the least. The novelty of this work lies in the combined analytical treatment of diverse waveform modulations while considering a uniform internal heat source and boundary condition for natural convection. 2025 The Author(s)
creator: Kruthik, P.S.; Idris, Ruwaidiah; Siddheshwar, P.G.
source: Results in Engineering;Volume;27;Issue;;Article No.;106047;
publisher: Elsevier B.V.
date: 01-01-2025
rights: All Open Access; Gold Open Access; Green Open Access
relation: ISSN: 25901230;
format: online
language: English
type: Article
coverage: Kruthik P.S., Special Interest Group for Modelling and Data Analytics (SIGMDA), Faculty of Computer Science and Mathematics, Universiti Malaysia Terengganu, Kuala Nerus, Terengganu, 21030, Malaysia; Idris R., Special Interest Group for Modelling and Data Analytics (SIGMDA), Faculty of Computer Science and Mathematics, Universiti Malaysia Terengganu, Kuala Nerus, Terengganu, 21030, Malaysia; Siddheshwar P.G., Centre for Mathematical Needs, Department of Mathematics, Christ University, Bengaluru, 560029, India

Study of Kpers?Lortz Instability in a Weakly Electrically Conducting Couple-Stress Fluid
subject: couple-stress fluid; Hartmann number; heat transfer; KpersLortz instability; magnetic field
description: The study aims to investigate the Kpers?Lortz instability in rotating RayleighBard convection of a weakly electrically conducting couple-stress fluid. A novel aspect of this study is the incorporation of weakly electrically conducting couple-stress fluid in a rotating RayleighBard setup to analyze Kpers?Lortz instability and examine heat transfer in both primary and secondary regimes. The main goal is to understand how the combined effects of the couple-stress, rotation, and magnetic field alter stability thresholds and impact the heat transfer. KpersLortz instability (KLI) means the roll systems obtained during the regular convection get deformed and form an angle with each other, making the system unstable. The critical Rayleigh number for regular convection is obtained using linear stability analysis. A ninth-order Lorenz model is obtained using truncated Fourier expansions to study secondary instability. A weak magnetic field (Hartmann number) and couple-stress parameter hinders the onset-of-regular convection. We also obtain the critical values at which the KLI manifests. The critical values are found at a marginal steady state. The Hartmann number and couple-stress parameters hinder the onset-of-secondary instability. Further, the Nusselt number expression is derived, and it is observed that an increase in the couple-stress parameter and Hartmann number diminishes the heat transfer. Additionally, the Nusselt number is obtained for primary and secondary regimes, showing the impact of the parameters on the efficiency of heat transfer in each regime. To validate the results on secondary instability, the study compares its findings with existing literature in the absence of a weak magnetic field and couple-stress effects. A reasonably good agreement is observed, confirming the reliability of the results. 2025 Wiley Periodicals LLC.
creator: Reddy, B. Sirisha; Pranesh, S.; Siddheshwar, P.G.
source: Heat Transfer;Volume;54;Issue;6;pp.3947-3959
publisher: John Wiley and Sons Inc
date: 01-01-2025
rights: Restricted Access; Hardcopy may be available in the library
relation: ISSN: 26884534;
format: online
language: English
type: Article
coverage: Reddy B.S., Centre for Mathematical Needs, Department of Mathematics, Christ University, Karnataka, Bengaluru, India; Pranesh S., Centre for Mathematical Needs, Department of Mathematics, Christ University, Karnataka, Bengaluru, India; Siddheshwar P.G., Centre for Mathematical Needs, Department of Mathematics, Christ University, Karnataka, Bengaluru, India

Study of linear and non-linear analyses of rayleigh-benard chandrasekhar convection in micropolar fluid with saturated porous medium
subject: Mathematics and Statistics
description: Thermal instability of Chandrasekhar convection in a micropolar fluid, saturated porous layer is being investigated in this study. The model is confined between two horizon- tal plates of infinite length and separated by a fixed distance. A uniform temperature gradient is provided at the lower plate, while the upper plate is cooled. The study is analysed for both linear as well as non-linear cases to understand the stability, transfer of heat and mass within the model. The study is carried out in extending the model for Rayleigh-Benard and double diffusive convection with external constraints such as in-ternal heat, concentration source, gravity modulation, temperature modulation, coupled cross diffusion and throughflow. The outcome of the study is discussed in detail and presented pictorially through graphs. Linear and Non-linear Analyses of Double Diffusive Chandrasekhar Convection with Heat and Concentration Source in Micropolar Fluid with Saturated Porous Media under Gravity Modulation. A thermosolutal convective study is carried out in the presence of externally imposed magnetic field and gravity modulation together with heat and concentration source in a micropolar fluid. This problem is analysed for both linear and non-linear cases by as- suming the strength of heat and concentration source same. The expression for critical thermal Rayleigh number and correction thermal Rayleigh number are obtained using regular perturbation method to understand the stability of problem. The transfer of heat and mass transport is investigated by deriving the eighth order Lorentz equation. It is found that internal Rayleigh number and Darcy number speeds up the onset of instabil-ity while the coupling parameter and Chandrasekhar number has a reverse effect. Also, the transfer of mass is more compared to the transfer of heat. Linear and Non-linear Analyses of Double Diffusive Chandrasekhar Convection Coupled with Cross-diffusion in Micropolar Fluid over Saturated Porous Medium …
creator: Anncy, Maria S.
source: Author's Submission
publisher: Christ(Deemed to be University)
date: 2021-01-01
contributor: Joseph, T V and Pranesh, S
rights: Open Access
relation: 61000156
format: PDF
language: English
type: PhD

Study of linear and non-linear analyses of Rayleigh-Benard-Chandrasekhar convecion in micropolar fluid with saturated porous medium
subject: Mathematics
description: Thermal instability of Chandrasekhar convection in a micropolar fluid, saturated porous layer is being investigated in this study. The model is confined between two horizontal plates of infinite length and separated by a fixed distance. A uniform temperature gradient is provided at the lower plate, while the upper plate is cooled. The study is analysed for both linear as well as non-linear cases to understand the stability, transfer of heat and mass within the model. The study is carried out in extending the model for Rayleigh-Benard and double diffusive convection with external constraints such as in- ´ ternal heat, concentration source, gravity modulation, temperature modulation, coupled cross diffusion and throughflow. The outcome of the study is discussed in detail and presented pictorially through graphs.
creator: S, Maria Anncy - 1540086
publisher: CHRIST (Deemed to be University)
language: English
type: PhD

Study of Low-Mass Stars and Brown Dwarfs In Star Forming Regions of Diverse Environments
subject: Physics and Electronics
description: The formation and evolution of low-mass stars and brown dwarfs is an intricate process orchestrated by the environmental conditions in which they form. As a natural byproduct of this process, circumstellar disks are formed, whose dynamic relationship with the environment plays a pivotal role in determining the fate of the star and the timescale for planet formation. While low-mass stars are a dominant product of the star formation process, brown dwarfs occupy a unique position, bridging the gap between newlinelow-mass stars and planets. In this thesis, we have examined the low-mass stars and brown dwarfs in young clusters located at different distances with diverse UV radiation felds and stellar densities to decode the role of environment in shaping the IMF, its inand#64258;uence on disk evolution and to understand the formation of brown dwarfs. We have targeted three young star forming regions for the newlinestudy namely and#963; Orionis, twin clusters IC 1848-East and West, and IC 1396 using deep multi-wavelength photometry as well as near-IR spectroscopy with 4m and 10m class facilities. For the and#963; Orionis cluster we used deep CFHT-WIRCAM near-IR data and the novel water-band photometry technique along with Gaia DR3 to identify the candidate low-mass members. Spectroscopic follow-up observations conducted with IRTF-SpeX validated the selection of the candidates by this technique with a 100% effcacy. We then compiled a comprehensive membership catalog for a mass range and#8764;19-0.004 Mand#8857;. The form of the stellar-substellar IMF was found to be consistent with other nearby star forming regions suggesting a lack of signifcant environmental inand#64258;uence. Further, we analysed the evolutionary class of the members based on the mid-IR slope of the SED to study their disk properties. We estimated the disk fraction of the low-mass sources to be consistent with other star form ing regions considering the age of the cluster. This showed that in this regio…
creator: Damian, Belinda
source: Author's Submission
publisher: Christ(Deemed to be University)
date: 2024-01-01
contributor: S Kartha, Sreeja and Jose, Jessy
rights: Open Access
relation: 61000366
format: PDF
language: English
type: PhD

Study of magnetoconvection with maxwell cattaneo law
subject: Mathematics and Statistics
description: This thesis deals with the study of Rayleigh-Bard-convection in a Newtonian fluid and micropolar fluid by replacing the classical Fourier law by non-classical Maxwell-Cattaneo heat flux law. The effects of second sound, non-uniform basic temperature gradients, suctioninjection-combination, temperature modulation and gravity modulation in newlinepresence of external constraints like magnetic field and rotation are studied. newlineThe problems investigated in this thesis throw light on externally controlled convection in Newtonian and micropolar fluids in the presence of Maxwell-Cattaneo law. The problems investigated in this thesis deal newlinewith practical problems with very large heat fluxes and/or short time duration. With this motivation, we investigate in this thesis five problems and their summary is given below. (i) Effects of Coriolis force and non-uniform basic temperature gradients on the onset of Rayleigh-Bard-Chandrasekhar newlineconvection with Maxwell-Cattaneo law The effect of non-uniform temperature gradient on RayleighBard-Chandrasekhar convection in a rotating Newtonian fluid with Maxwell-Cattaneo law is studied using the Galerkin technique. The eigenvalues is obtained for free-free, rigid-free and rigid-rigid velocity boundary combinations with isothermal and adiabatic boundaries. A linear stability analysis is performed. The influence of various parameters on the onset of convection has been analyzed. One linear and five non-linear temperature profiles are considered and their comparative influence on onset is discussed. It is found that the results are noteworthy at short times and the critical eigenvalues are less than the classical ones. It is shown that the system having magnetic field will delay in the onset newlineof instability. In general, it is observed that step function and inverted parabolic temperature profile are the most destabilizing and stabilizing profiles.
creator: Kiran, R V.
source: Author's Submission
publisher: Christ(Deemed to be University)
date: 2013-01-01
contributor: Pranesh, S
rights: Open Access
relation: No Thesis
format: PDF
language: English
type: PhD

Study of magnetoconvection with maxwell cattaneo law /
subject: Mathematics
description: This thesis deals with the study of Rayleigh-Bénard-convection in a Newtonian fluid and micropolar fluid by replacing the classical Fourier law by non-classical Maxwell-Cattaneo heat flux law. The effects of second sound, non-uniform basic temperature gradients, suctioninjection-combination, temperature modulation and gravity modulation in presence of external constraints like magnetic field and rotation are studied. The problems investigated in this thesis throw light on externally controlled convection in Newtonian and micropolar fluids in the presence of Maxwell-Cattaneo law. The problems investigated in this thesis deal with practical problems with very large heat fluxes and/or short time duration. With this motivation, we investigate in this thesis five problems and their summary is given below. (i) Effects of Coriolis force and non-uniform basic temperature gradients on the onset of Rayleigh-Bénard-Chandrasekhar convection with Maxwell-Cattaneo law The effect of non-uniform temperature gradient on RayleighBénard-Chandrasekhar convection in a rotating Newtonian fluid with Maxwell-Cattaneo law is studied using the Galerkin technique. The eigenvalues is obtained for free-free, rigid-free and rigid-rigid velocity boundary combinations with isothermal and adiabatic boundaries. A linear stability analysis is performed. The influence of various parameters on the onset of convection has been analyzed. One linear and fiveix non-linear temperature profiles are considered and their comparative influence on onset is discussed. It is found that the results are noteworthy at short times and the critical eigenvalues are less than the classical ones. It is shown that the system having magnetic field will delay in the onset of instability. In general, it is observed that step function and inverted parabolic temperature profile are the most destabilizing and stabilizing profiles. The range of values of the parameters of the problem for which oscillatory convection in the case o…
creator: Kiran, R.V. - 0944302
publisher: CHRIST (Deemed to be University)
date: 2013-12-22
language: English
type: PhD

Study of micro and small enterprises' readiness in implementing industry 4.0: A study in marathwada district of maharashtra, india
description: Industry 4.0 aims tp transform the development of global value chains and the development of a digital revolution, with intelligent machines capable of communicating via wireless connections and a connection thought system, resulting in autonomous decision-making. Although large sized firms are adopting Industry 4.0, the small and micro enterprises are facing great difficulties in adopting them. This study aims to identify the areas in which Enterprises need to focus for improving their level of readiness and develop strategies and plans to adopt Industry 4.0 technologies successfully. 219 samples were collected using snowball sampling from Marathwada District in Maharashtra, India. factor analysis was conducted using SPSS and different factors acting as barriers to implementation of Industry 4.0 technologies were identified. 2023 by IGI Global. All rights reserved.
creator: Saha S.K.; Deshmukh J.R.; Ramakrishnan N.
source: Developing Skills and Competencies for Digital and Green Transitions, pp. 263-280.
publisher: IGI Global
date: 2023-01-01
rights: Restricted Access
relation: ISBN: 978-166849090-7; 978-166849089-1
format: Online
language: English
type: Book chapter
coverage: Saha S.K., Christ University, India; Deshmukh J.R., Christ University, India; Ramakrishnan N., Christ University, India

Study of mineral and nutritional composition of some seaweeds found along the coast of Gulf of Mannar, India
subject: Food industry; Gulf of Mannar; Seaweeds; Trace minerals
description: The presence of Algae on the Earth is ubiquitous. The industry that widely uses algae is food industry, where the algae are used as a food supplement and also as an addition to the nutrient rich food. This study emphasizes on the mineral and nutritional composition of the selected fourteen algal species which are abundantly found along the coast of the Gulf of Mannar. The selected species of algae belong to different algal families such as Chlorophyta, Phaeophyta and Rhodophyta. The amount of minerals such as Ca, Zn, Fe, K, Mg, Mn, and Cu were estimated by employing the method of acid digestion followed by atomic absorption spectroscopy. We estimated the nutritional content based on the assessment of total protein, carbohydrate, phenol, ash and moisture contents of the algal species. The results based on the analysis of the mineral content in the algal seaweeds depicted that the seaweeds comprised of high amount of the macro minerals and trace minerals. Estimation of nutritional composition revealed that these algal species are rich in protein and carbohydrate. The ash contents were found to be very high in Jania rubens (86.66%), Padina boergesenii (85%) and Valoniopsis pachynema (84%). Based on the present study we infer that the algal seaweeds contained high amount of the nutritional compounds, which might pave the way for a higher standard of nutritional supply to the humans in the future. Jose & Xavier (2020). This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited (https://creativecommons.org/licenses/by/4.0/).
creator: Jose J.; Xavier J.
source: Plant Science Today, Vol-7, No. 4, pp. 631-637.
publisher: Horizon e-Publishing Group
date: 2020-01-01
rights: All Open Access; Gold Open Access
relation: ISSN: 23481900
format: Online
language: English
type: Article
coverage: Jose J., Department of Life Sciences, CHRIST (Deemed to be University), Bangalore, Karnataka, 560 029, India; Xavier J., Department of Life Sciences, CHRIST (Deemed to be University), Bangalore, Karnataka, 560 029, India

Study of multilayer flow of a bi-viscous Bingham fluid sandwiched between hybrid nanofluid in a vertical slab with nonlinear Boussinesq approximation
description: Bi-viscosity Bingham plastic fluids are used to understand the rheological characteristics of pigment-oil suspensions, polymeric gels, emulsions, heavy oil, etc. In many industrial and engineering problems involving high-temperature situation, a linear density-temperature variation is inadequate to describe the convective heat transport. Therefore, the characteristics of the nonlinear convective flow of a bi-viscous Bingham fluid (BVBF) through three layers in a vertical slab are studied. The two outer layers of the oil-based hybrid nanofluid and the intermediate layer of BVBF are considered. The thermal buoyancy force is governed by the nonlinear Boussinesq approximation. Continuity of heat flux, velocity, shear stress, and temperature are imposed on the interfaces. The governing equations are derived from the Navier-Stokes equation, conservation of energy, and conservation of mass for three layers. The nonlinear multi-point (four-point) boundary value problem is solved using the differential transform method (DTM). Converging DTM solutions are obtained, and they are validated. The entropy equation and Bejan number were also derived and analyzed. It is established that the nonlinear density-temperature variation leads to a significant improvement in the magnitude of the velocity and temperature profiles due to the increased buoyancy force, and as a result, the drag force on the walls gets reduced. The drag force on the slab gets reduced by decreasing the volume fraction of nanoparticles. Furthermore, nonlinear convection and mixed convection give rise to an advanced rate of heat transport on the walls and thereby to an enhanced heat transport situation. 2022 Author(s).
creator: Basavarajappa M.; Myson S.; Vajravelu K.
source: Physics of Fluids, Vol-34, No. 12
publisher: American Institute of Physics Inc.
date: 2022-01-01
rights: Restricted Access
relation: ISSN: 10706631; CODEN: PHFLE
format: Online
language: English
type: Article
coverage: Basavarajappa M., School of Mathematical and Statistical Sciences, The University of Texas Rio Grande Valley, Edinburg, 78531, TX, United States; Myson S., Center for Mathematical Needs, Department of Mathematics, Christ (Deemed to Be University), Karnataka, Bengaluru, 560029, India; Vajravelu K., Department of Mathematics, University of Central Florida, Orlando, 32816, FL, United States

Study of multilayer flow of non-Newtonian fluid sandwiched between nanofluids
subject: Differential transform method; Entropy generation analysis; Hybrid nanofluid; Multilayer flow; Nonlinear Boussinesq approximation; Third-grade fluid
description: This theoretical investigation examines the nonlinear convective heat transport and multilayer flow of a non-Newtonian fluid within a vertical slab, incorporating viscous heating effects. The middle layer of the slab contains a third-grade fluid, while the outer layers are filled with a water-based Ag-MgO hybrid nanoliquid. Continuity in temperature, heat flux, velocity, and shear stress is maintained at the interfaces of the fluid layers. The thermal buoyancy force is modeled using the nonlinear Boussinesq approximation. The governing system comprises conservation equations for mass, momentum (Navier-Stokes), and energy for each of the three layers. These differential equations are non-dimensionalized, and the resulting dimensionless four-point nonlinear boundary value problem is transformed into a two-point boundary value problem before being solved numerically. For limiting cases, analytical and semi-analytical solutions are computed and used as benchmark results to validate the numerical method employed. Entropy generation analysis indicates that higher third-grade fluid parameters reduce the magnitude of velocity and temperature fields, as well as entropy production across all regions. The third-grade fluid parameter shows a decreasing influence on velocity and temperature fields throughout the system. The continuity of interfacial conditions induces a dragging effect; despite the absence of third-grade fluid parameters in regions I and III, their influence is apparent in these regions. The Bejan number slightly decreases at the walls with increasing third-grade fluid parameters, exhibiting a dual effect in the third-grade fluid layer. Near the walls, the Bejan number decreases as the nanoparticle volume fraction increases. Findings of this work may have applications in polymer industries and processes involving high temperatures. 2024
creator: Myson S.; Basavarajappa M.; Vajravelu K.
source: Partial Differential Equations in Applied Mathematics, Vol-13
publisher: Elsevier B.V.
date: 2025-01-01
rights: Restricted Access
relation: ISSN: 26668181
format: Online
language: English
type: Article
coverage: Myson S., Center for Mathematical Needs, Department of Mathematics, CHRIST (Deemed to be University), Karnataka, Bengaluru, 560029, India; Basavarajappa M., Center for Mathematical Needs, Department of Mathematics, CHRIST (Deemed to be University), Karnataka, Bengaluru, 560029, India, Department of Mathematics and Physics, Texas A&M International University, Laredo, 78041, TX, United States; Vajravelu K., Department of Mathematics, University of Central Florida, Orlando, 32816, FL, United States

Study of multilayer flow of non-Newtonian fluid sandwiched between nanofluids
subject: Differential transform method; Entropy generation analysis; Hybrid nanofluid; Multilayer flow; Nonlinear Boussinesq approximation; Third-grade fluid
description: This theoretical investigation examines the nonlinear convective heat transport and multilayer flow of a non-Newtonian fluid within a vertical slab, incorporating viscous heating effects. The middle layer of the slab contains a third-grade fluid, while the outer layers are filled with a water-based Ag-MgO hybrid nanoliquid. Continuity in temperature, heat flux, velocity, and shear stress is maintained at the interfaces of the fluid layers. The thermal buoyancy force is modeled using the nonlinear Boussinesq approximation. The governing system comprises conservation equations for mass, momentum (Navier-Stokes), and energy for each of the three layers. These differential equations are non-dimensionalized, and the resulting dimensionless four-point nonlinear boundary value problem is transformed into a two-point boundary value problem before being solved numerically. For limiting cases, analytical and semi-analytical solutions are computed and used as benchmark results to validate the numerical method employed. Entropy generation analysis indicates that higher third-grade fluid parameters reduce the magnitude of velocity and temperature fields, as well as entropy production across all regions. The third-grade fluid parameter shows a decreasing influence on velocity and temperature fields throughout the system. The continuity of interfacial conditions induces a dragging effect; despite the absence of third-grade fluid parameters in regions I and III, their influence is apparent in these regions. The Bejan number slightly decreases at the walls with increasing third-grade fluid parameters, exhibiting a dual effect in the third-grade fluid layer. Near the walls, the Bejan number decreases as the nanoparticle volume fraction increases. Findings of this work may have applications in polymer industries and processes involving high temperatures. 2024
creator: Myson, Shruthy; Basavarajappa, Mahanthesh; Vajravelu, Kuppalapalle
source: Partial Differential Equations in Applied Mathematics;Volume;13;Issue;;Article No.;101053;
publisher: Elsevier B.V.
date: 01-01-2025
rights: All Open Access; Gold Open Access; Green Open Access
relation: ISSN: 26668181;
format: online
language: English
type: Article
coverage: Myson S., Center for Mathematical Needs, Department of Mathematics, CHRIST (Deemed to be University), Karnataka, Bengaluru, 560029, India; Basavarajappa M., Center for Mathematical Needs, Department of Mathematics, CHRIST (Deemed to be University), Karnataka, Bengaluru, 560029, India, Department of Mathematics and Physics, Texas A&M International University, Laredo, 78041, TX, United States; Vajravelu K., Department of Mathematics, University of Central Florida, Orlando, 32816, FL, United States

Study of multilayer flow of two immiscible nanofluids in a duct with viscous dissipation
description: Numerical simulations for the mixed convective multilayer flow of two different immiscible nanofluids in a duct with viscous heating effects were performed in this study. The left and right faces of the duct are maintained to be isothermal, while other side faces are insulated. The mathematical governing system for each layer consists of an incompressibility condition equation, the Navier-Stokes momentum equation, and the conservation of energy equation. At the interface of the immiscible layer, the continuity of velocity, shear stress, temperature, and heat flux are considered. The dimensionless equations governing each layer were numerically integrated using the finite difference method and the Southwell-over-relaxation method. A mesh independence test is conducted. Furthermore, a parametric study is performed to analyze how the different nanoparticle volume fractions and viscous heating affect the transport characteristics of engine oil-copper and mineral oil-silver nanofluids. The study also examined the effects of various types of nanoparticles and base fluids. The results demonstrated that heat transport could be efficiently controlled by considering the viscous heating aspect. Moreover, the effects of different nanoparticles on heat transport were found to be more significant than those of base fluids. Finally, a point-wise comparison of our numerical results demonstrates a good agreement with existing studies in the literature. 2023 Author(s).
creator: Umavathi J.C.; Basavarajappa M.
source: Physics of Fluids, Vol-35, No. 9
publisher: American Institute of Physics Inc.
date: 2023-01-01
rights: Restricted Access
relation: ISSN: 10706631; CODEN: PHFLE
format: Online
language: English
type: Article
coverage: Umavathi J.C., Department of Mathematics, Gulbarga University, Karnataka, Gulbarga, 585106, India; Basavarajappa M., School of Mathematical and Statistical Sciences, The University of Texas Rio Grande Valley, Edinburg, 78539, TX, United States, Center for Mathematical Needs, Department of Mathematics, CHRIST (Deemed to be University), Karnataka, Banglore, 560029, India

Study of nanofluid flow and heat transfer in a stationary cone-disk system
subject: Buongiorno model; Cone-disk system; Nanofluid; Nusselt number; Swirling flow
description: Rheometric, viscosimetric, bio-medical, and several other pharmaceutical machineries utilize the structural advantages provided by the geometry of a stationary conical diffuser. The problem of the Buongiorno nanofluid flow in the conical gap of a stationary cone-disk system for isothermal boundaries is studied. The governing system, comprising the incompressibility condition, NavierStokes equation, energy conservation equation, and conservation of Nanoparticle Volume Fraction (NVF) equation, is analyzed. The Lie-group theory has been used to derive a self-similar model. Solutions of the self-similar equations were computed numerically, and the expressions for the Nusselt number and Sherwood number are obtained. The parametric investigation reveals that the heat and mass transfer rate subside significantly when pre-swirl is introduced to the flow. Furthermore, the nanofluid slip mechanisms enhance the effective temperature of the system. 2023 Elsevier Ltd
creator: John A.S.; Mahanthesh B.; Shevchuk I.V.
source: Thermal Science and Engineering Progress, Vol-46
publisher: Elsevier Ltd
date: 2023-01-01
rights: Restricted Access
relation: ISSN: 24519049
format: Online
language: English
type: Article
coverage: John A.S., Center for Mathematical Needs, Department of Mathematics, CHRIST (Deemed to be University), Karnataka, Bangalore, 560029, India; Mahanthesh B., Center for Mathematical Needs, Department of Mathematics, CHRIST (Deemed to be University), Karnataka, Bangalore, 560029, India, School of Mathematical and Statistical Sciences, The University of Texas Rio Grande Valley, Edinburg, 78539, TX, United States; Shevchuk I.V., Faculty of Computer Science and Engineering Science, TH Koln-University of Applied Sciences, Gummersbach, 51643, Germany

Study of nanofluid flow in a stationary cone-disk system with temperature-dependent viscosity and thermal conductivity
description: The substantial temperature gradient experienced by systems operating at relatively high temperatures significantly impacts the transport characteristics of fluids. Hence, considering temperature-dependent fluid properties is critical for obtaining realistic prediction of fluid behavior and optimizing system performance. The current study focuses on the flow of nanofluids in a stationary cone-disk system (SCDS), taking into account temperature-dependent thermal conductivity and viscosity. The influence of Brownian motion, thermophoresis, and Rosseland radiative flux on the heat transport features are also examined. The Reynolds model for viscosity and Chiam's model for thermal conductivity are employed. The Navier-Stokes equation, the energy equation, the incompressibility condition, and the continuity equation for nanoparticles constitute the governing system. The Lie-group transformations lead the self-similar ordinary differential equations, which are then solved numerically. Multi-variate non-linear regression models for the rate of heat and mass transfers on the disk surface were developed. Our study reveals a notable decrease in the rate of heat and mass transfer when pre-swirl exists in the flow. The significant influence of nanofluid slip mechanisms on the effective temperature and nanofluid volume fraction (NVF) within the system is highlighted. Furthermore, the variable viscosity property enhances the temperature and NVF of the SCDS. 2024 Author(s).
creator: John A.S.; Basavarajappa M.; Shevchuk I.V.
source: Physics of Fluids, Vol-36, No. 5
publisher: American Institute of Physics
date: 2024-01-01
rights: Restricted Access
relation: ISSN: 10706631; CODEN: PHFLE
format: Online
language: English
type: Article
coverage: John A.S., Center for Mathematical Needs, Department of Mathematics, CHRIST (Deemed to be University), Karnataka, Bangalore, 560029, India; Basavarajappa M., Center for Mathematical Needs, Department of Mathematics, CHRIST (Deemed to be University), Karnataka, Bangalore, 560029, India, School of Mathematical and Statistical Sciences, The University of Texas Rio Grande Valley, Edinburg, 78539, TX, United States; Shevchuk I.V., Faculty of Computer Science and Engineering Science, TH Koln-University of Applied Sciences, Gummersbach, 51643, Germany

Study of Nanolayered Structure of Commercially Available Carbon Materials and Soot
description: Developments in the modern world periodically call for the discovery or invention of new and exotic materials. In the present situation, to develop unique and novel materials, which move beyond the barriers of the physical limits of the amount of micro- miniaturization possible as well as the current technology and take advantage of the opportunities not yet imagined, is not at all a need but a necessity. The advent of Nano technology of carbon allotropes is a giant leap towards this goal. The starting of the era of carbon nanomaterials traces back to 1985 when the fullerenes with a foot ball structure were accidently discovered. From then on, the field of carbon nanotechnology was in the constant limelight on account of the amazing properties displayed by the various allotropes of carbon. These properties are dependent mainly on the type of hybridization present in the nanostructures, which categorizes them to amorphous or crystalline. Also, there exist some structures which are the combination of these two and are termed as nanocrystalline or turbostratic structures. The discovery of graphene, which has a turbostratic structure and is the thinnest material known and the strongest ever measured, with outstanding properties such as highest room temperature electrical conductivity; high mechanical robustness etc was a ground breaking one. These remarkable properties open up a wide range of potential applications ranging from clean energy to nano-electronics to bio-medical devices. Thus, it is a necessity to explore and characterize various effective sources of these nanomaterials. The present study is an attempt to investigate such efficient, easily available and cost-effective precursors. Soot, also known as black carbon, is a fine-grained solid residue that results from incomplete combustion of hydrocarbons and is a widely used precursor for the production of carbon nanomaterials. Carbon soot is a major component of smoke from the combustion of carbon-rich organic …
creator: .N.Mohan Anu
source: Physics
date: 2012

Study of Natural Convection with Local Thermal Non Equilibrium Effects in Nanoliquid-Saturated Low Porosity Enclosures
subject: Darcy model; Enclosures; Local thermal non-equilibrium (LTNE); Nanoliquid; Natural convection; Porous medium; Single-phase model
description: Natural convection of nanoliquid in densely packed vertical porous enclosure is studied by subjecting the vertical walls to constant heat flux under local thermal non-equilibrium (LTNE) assumptions. Water, copper nanoparticles and porous material made of aluminum foam, glass balls and sand are considered for the study. The governing equations are modelled using single-phase model. Thermophysical properties of nanoliquid and nanoliquid-saturated porous medium are calculated using phenomenological laws and mixture theory. An analytical expression for velocity and temperature profiles of nanoliquid (base liquid+nanoparticles) and solid (porous medium) phases has been obtained. Weighted average Nusselt number is expressed as a function of aspect ratio, volume fraction, and properties concerning LTNE effects. LTNE effect is shown to be a heat transfer enhancing mechanism. The presence of nanoparticles is to enhance the heat transfer in water. Local thermal equilibrium results are obtained as a limiting case of the present study and so obtained results are compared with previously published paper in the literature. 2022, The Author(s), under exclusive licence to Springer Nature India Private Limited.
creator: Siddheshwar P.G.; Veena B.N.
source: International Journal of Applied and Computational Mathematics, Vol-8, No. 1
publisher: Springer
date: 2022-01-01
rights: Restricted Access
relation: ISSN: 23495103
format: Online
language: English
type: Article
coverage: Siddheshwar P.G., Centre for Mathematical Needs, Department of Mathematics, Christ (Deemed to be University), Bengaluru, 560029, India; Veena B.N., Department of Mathematics, M. S. Ramaiah Institute of Technology, M S Ramaiah Nagar, Bengaluru, 560054, India