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V. Ramachandra Prasad - One of the best experts on this subject based on the ideXlab platform.

  • Entropy generation of tangent hyperbolic nanofluid flow over a circular cylinder in the presence of nonlinear Boussinesq Approximation: a non-similar solution
    Journal of Thermal Analysis and Calorimetry, 2020
    Co-Authors: H. Thameem Basha, R. Sivaraj, V. Ramachandra Prasad
    Abstract:

    The analysis of entropy generation has received notable attention in the study of nanofluids because the prime objective of nanofluids is to admit high heat fluxes. The entropy production can be utilized to generate the entropy in any irreversible heat transfer process which is important in thermal machines. This work presents to explore the fluid transport characteristics and entropy generation of a tangent hyperbolic nanofluid over a horizontal circular cylinder with the influence of nonlinear Boussinesq Approximation. The dimensionless nonlinear partial differential equations have been solved by using an implicit finite difference Keller box scheme. The impacts of active parameters on the flow field like Weissenberg number, power-law index, magnetic field, mixed convection, Brownian motion, thermal convention, thermophoresis and radiation are illustrated with graphs and tables. The current results exposed that the nanofluid velocity enhances for enhancing the mixed convection parameter. Isotherms thickness is escalated with increasing values of radiation parameter. Total entropy generation rises for higher values of dimensionless temperature ratio parameter.

Antonio Barletta - One of the best experts on this subject based on the ideXlab platform.

  • Extended Oberbeck–Boussinesq Approximation study of convective instabilities in a porous layer with horizontal flow and bottom heating
    International Journal of Heat and Mass Transfer, 2010
    Co-Authors: Donald A. Nield, Antonio Barletta
    Abstract:

    Abstract A study of the onset of convective instabilities in a porous layer with a horizontal basic flow is performed by including the effects of viscous dissipation and pressure work in the energy balance. Firstly, the so-called extended Oberbeck–Boussinesq Approximation, i.e. the model based on the enthalpy formulation of the energy balance, is adopted. Then, the results for the marginal stability condition are compared with those obtained by the so-called Chandrasekhar Approximation, i.e. the model based on the internal-energy formulation of the energy balance. It is shown that a marked discrepancy occurs between the two approaches, that becomes specially evident for high values of the Gebhart number. According to the extended Oberbeck–Boussinesq Approximation, the effects of the viscous dissipation and of the pressure work result in a stabilization of the basic flow. On the contrary, the Chandrasekhar Approximation predicts a destabilization of the basic flow induced by the viscous dissipation. The destabilization can be so intense that the onset of convective rolls may occur even in the absence of a boundary temperature difference, i.e. with a vanishing Darcy–Rayleigh number.

  • Local energy balance, specific heats and the Oberbeck–Boussinesq Approximation
    International Journal of Heat and Mass Transfer, 2009
    Co-Authors: Antonio Barletta
    Abstract:

    Abstract A thermodynamic argument is proposed in order to discuss the most appropriate form of the local energy balance equation within the Oberbeck–Boussinesq Approximation. The study is devoted to establish the correct thermodynamic property to be used in order to express the relationship between the change of internal energy and the temperature change. It is noted that, if the fluid is a perfect gas, this property must be identified with the specific heat at constant volume. If the fluid is a liquid, a definitely reliable Approximation identifies this thermodynamic property with the specific heat at constant pressure. No explicit pressure work term must be present in the energy balance. The reasoning is extended to the case of fluid saturated porous media.

  • local energy balance specific heats and the oberbeck Boussinesq Approximation
    International Journal of Heat and Mass Transfer, 2009
    Co-Authors: Antonio Barletta
    Abstract:

    Abstract A thermodynamic argument is proposed in order to discuss the most appropriate form of the local energy balance equation within the Oberbeck–Boussinesq Approximation. The study is devoted to establish the correct thermodynamic property to be used in order to express the relationship between the change of internal energy and the temperature change. It is noted that, if the fluid is a perfect gas, this property must be identified with the specific heat at constant volume. If the fluid is a liquid, a definitely reliable Approximation identifies this thermodynamic property with the specific heat at constant pressure. No explicit pressure work term must be present in the energy balance. The reasoning is extended to the case of fluid saturated porous media.

  • Local energy balance, specific heats and the Oberbeck–Boussinesq Approximation
    International Journal of Heat and Mass Transfer, 2009
    Co-Authors: Antonio Barletta
    Abstract:

    A thermodynamic argument is proposed in order to discuss the most appropriate form of the local energy balance equation within the Oberbeck-Boussinesq Approximation. The study is devoted to establish the correct thermodynamic property to be used in order to express the relationship between the change of internal energy and the temperature change. It is noted that, if the fluid is a perfect gas, this property must be identified with the specific heat at constant volume. If the fluid is a liquid, a definitely reliable Approximation identifies this thermodynamic property with the specific heat at constant pressure. No explicit pressure work term must be present in the energy balance. The reasoning is extended to the case of fluid saturated porous media.Comment: 14 pages, 2 figures, 1 table, submitted for publicatio

H. Thameem Basha - One of the best experts on this subject based on the ideXlab platform.

  • Entropy generation of tangent hyperbolic nanofluid flow over a circular cylinder in the presence of nonlinear Boussinesq Approximation: a non-similar solution
    Journal of Thermal Analysis and Calorimetry, 2020
    Co-Authors: H. Thameem Basha, R. Sivaraj, V. Ramachandra Prasad
    Abstract:

    The analysis of entropy generation has received notable attention in the study of nanofluids because the prime objective of nanofluids is to admit high heat fluxes. The entropy production can be utilized to generate the entropy in any irreversible heat transfer process which is important in thermal machines. This work presents to explore the fluid transport characteristics and entropy generation of a tangent hyperbolic nanofluid over a horizontal circular cylinder with the influence of nonlinear Boussinesq Approximation. The dimensionless nonlinear partial differential equations have been solved by using an implicit finite difference Keller box scheme. The impacts of active parameters on the flow field like Weissenberg number, power-law index, magnetic field, mixed convection, Brownian motion, thermal convention, thermophoresis and radiation are illustrated with graphs and tables. The current results exposed that the nanofluid velocity enhances for enhancing the mixed convection parameter. Isotherms thickness is escalated with increasing values of radiation parameter. Total entropy generation rises for higher values of dimensionless temperature ratio parameter.

R. Sivaraj - One of the best experts on this subject based on the ideXlab platform.

  • Entropy generation of tangent hyperbolic nanofluid flow over a circular cylinder in the presence of nonlinear Boussinesq Approximation: a non-similar solution
    Journal of Thermal Analysis and Calorimetry, 2020
    Co-Authors: H. Thameem Basha, R. Sivaraj, V. Ramachandra Prasad
    Abstract:

    The analysis of entropy generation has received notable attention in the study of nanofluids because the prime objective of nanofluids is to admit high heat fluxes. The entropy production can be utilized to generate the entropy in any irreversible heat transfer process which is important in thermal machines. This work presents to explore the fluid transport characteristics and entropy generation of a tangent hyperbolic nanofluid over a horizontal circular cylinder with the influence of nonlinear Boussinesq Approximation. The dimensionless nonlinear partial differential equations have been solved by using an implicit finite difference Keller box scheme. The impacts of active parameters on the flow field like Weissenberg number, power-law index, magnetic field, mixed convection, Brownian motion, thermal convention, thermophoresis and radiation are illustrated with graphs and tables. The current results exposed that the nanofluid velocity enhances for enhancing the mixed convection parameter. Isotherms thickness is escalated with increasing values of radiation parameter. Total entropy generation rises for higher values of dimensionless temperature ratio parameter.

  • Entropy generation of tangent hyperbolic nanofluid flow over a circular cylinder in the presence of nonlinear Boussinesq Approximation: a non-similar solution
    Journal of Thermal Analysis and Calorimetry, 2020
    Co-Authors: Ht Basha, R. Sivaraj, Vr Prasad, Oa Beg
    Abstract:

    The analysis of entropy generation has received notable attention in the study of nanofluids because the prime objective of nanofluids is to admit high heat fluxes. The entropy production can be utilized to generate the entropy in any irreversible heat transfer process which is important in thermal machines. This work presents to explore the fluid transport characteristics and entropy generation of a tangent hyperbolic nanofluid over a horizontal circular cylinder with the influence of nonlinear Boussinesq Approximation. The dimensionless nonlinear partial differential equations have been solved by using an implicit finite difference Keller box scheme. The impacts of active parameters on the flow field like Weissenberg number, power-law index, magnetic field, mixed convection, Brownian motion, thermal convention, thermophoresis and radiation are illustrated with graphs and tables. The current results exposed that the nanofluid velocity enhances for enhancing the mixed convection parameter. Higher values of nonlinear thermal convection parameter declines the thermal boundary thickness. Total entropy generation decreases for higher values of Eckert number. Isotherms thickness is escalated with increasing values of radiation parameter.

Jan Sokolowski - One of the best experts on this subject based on the ideXlab platform.

  • new approach to the incompressible maxwell Boussinesq Approximation existence uniqueness and shape sensitivity
    Journal of Differential Equations, 2010
    Co-Authors: Luisa Consiglieri, Šárka Nečasová, Jan Sokolowski
    Abstract:

    Abstract The Boussinesq Approximation to the Fourier–Navier–Stokes (F–N–S) flows under the electromagnetic field is considered. Such a model is the so-called Maxwell–Boussinesq Approximation. We propose a new approach to the problem. We prove the existence and uniqueness of weak solutions to the variational formulation of the model. Some further regularity in W 1 , 2 + δ , δ > 0 , is obtained for the weak solutions. The shape sensitivity analysis by the boundary variations technique is performed for the weak solutions. As a result, the existence of the strong material derivatives for the weak solutions of the problem is shown. The result can be used to establish the shape differentiability for a broad class of shape functionals for the models of Fourier–Navier–Stokes flows under the electromagnetic field.

  • Incompressible Maxwell-Boussinesq Approximation: Existence, uniqueness and shape sensitivity
    2009
    Co-Authors: Luisa Consiglieri, Šárka Nečasová, Jan Sokolowski
    Abstract:

    We prove the existence and uniqueness of weak solutions to the variational formulation of the Maxwell-Boussinesq Approximation problem. Some further regularity in $W^{1,2+\delta}$, $\delta>0$, is obtained for the weak solutions. The shape sensitivity analysis by the boundary variations technique is performed for the weak solutions. As a result, the existence of the strong material derivatives for the weak solutions of the problem is shown. The result can be used to establish the shape differentiability for a broad class of shape functionals for the models of Fourier-Navier-Stokes flows under the electromagnetic field.