Double-diffusive Hadley–Prats flow in a horizontal porous layer with a concentration based internal heat source

© 2017 Elsevier Inc. Double-diffusive Hadley–Prats flow with a concentration based heat source is investigated through linear and non-linear stability analyses. The resultant eigenvalue problems for both theories are solved numerically using Shooting and fourth order Runga–Kutta methods, with the critical thermal Rayleigh number being evaluated with respect to various flow governing parameters such as the magnitudes of the heat source and mass flow. It is observed, in the linear case, that an increase in the horizontal thermal Rayleigh number is stabilising for both positive and negative values of the solutal Rayleigh number. In the non-linear case, a destabilising effect is identified at higher mass flow rates. An increase in both the heat source and mass flow results in destabilisation

Influence of Internal Heat Source on Thermal Instability in a Horizontal Porous Layer with Mass Flow and Inclined Temperature Gradient

An investigation has been presented to analyze the effect of internal heat source on the onset of Hadley-Prats flow in a horizontal fluid saturated porous medium. We examine a better understanding of the combined influence of the heat source and mass flow effect by using linear stability analysis. The resultant eigenvalue problem is solved by using shooting and Runga-Kutta methods for evaluate critical thermal Rayleigh number with respect to various flow governing parameters. It is identified that the flow is switch from stabilizing to destabilizing as the horizontal thermal Rayleigh number is enhanced. The heat source and mass flow increases resulting a stronger destabilizing effect

Double-diffusive convection in an inclined porous layer with a concentration-based internal heat source

© 2017, The Author(s). The thermosolutal instability of double-diffusive convection in an inclined fluid-saturated porous layer with a concentration-based internal heat source is investigated. The linear instability of small-amplitude perturbations to the system is analyzed with respect to transverse and longitudinal rolls. The resultant eigenvalue problem is solved numerically utilizing the Chebyshev tau method. It is shown that an increasing inclination angle causes a strong stabilization in the transverse rolls irrespective of the internal heat source or vertical solutal Rayleigh number. Furthermore, substantial qualitative changes are demonstrated in the linear instability thresholds with variations in the inclination angle and concentration-based heat source

Nonlinear Stability of Convection in a Horizontal Porous Layer with Inclined Gradients

Convection in porous media is a highly active subject of research as it has very important applications in real life situations such as food processing, underground energy transport, cooling of nuclear reactors, geothermal reservoir engineering, solar power converters and oil extraction etc. Modelling these physical phenomena forms the main motivation behind the extensive research in this field and leads to the mathematical idealization of the stability of flows through the use of partial differential equations

Order of chemical reaction and convective boundary condition effects on micropolar fluid flow over a stretching sheet

The study of chemical reaction and convective boundary conditions on thermosolutal behavior of magneto hydrodynamic (MHD) fluid flow above a stretching sheet has been investigated in the current investigation. A mathematical model is established and the governing partial differential system is modified into a set of nonlinear coupled ordinary differential system and it is evaluated by using the numerical scheme of RK method. The physical importance of different flow variables such as the magnetic parameter, vortex viscosity parameter, order of chemical reaction, Prandtl, skin friction coefficient and Eckert numbers are discussed in detailed through graphical representation

The effects of Soret and Dufour, chemical reaction, Hall and ion currents on magnetized micropolar flow through co-rotating cylinders

The influence of cross diffusions, Hall and Ion slip of a dissipative magnetized micropolar fluid flow through an infinite concentric rotating vertical cylinders were investigated in addition to the first order chemical reaction. Cylinders are taken into account for Isothermal (constant temperature wall condition) and mixed gradient condition at inner cylinder, while convection cooling and constant wall concentration condition is taken at outer cylinder. The governing equations in cylindrical polar coordinates are coupled ordinary differential equations (ODEs) and are solved numerically with help of Shooting method with fourth order Runge Kutta method. A parametric study illustrating the influence of the emerging parameters on flow, heat and mass transfer components as well as on Skin Friction, Nusselt number and Sherwood number through graphical illustrations

Enhancing Secure Communication in the Cloud Through Blockchain Assisted-CP-DABE

The use of encryption is essential to protect sensitive data, but it often poses challenges when it comes to locating and retrieving information without decryption. Searchable encryption provides an effective mechanism that achieves secure search over encrypted data. In this paper a new approach to address the fine-grained search and to protect sensitive data, Blockchain Assisted ciphertext policy decentralized attribute-based encryption (BA-CP-DABE) in cloud has been developed. The CP-DABE is employed to manage data access, secure key generation, while the immutability of blockchain ensures the confidentiality of ciphertext. By leveraging searchable encryption, it becomes possible to securely search encrypted data stored on the blockchain. Keywords are encrypted using attribute-based encryption and stored on a remote server, along with the corresponding ciphertext in the blockchain. One of the significant challenges in this approach is the assumptions-based technique i.e., bilinear mapping, which involves keyword ciphertext and trapdoor security. However, through extensive numerical experiments, the system has demonstrated its ability to generate key and trapdoor structures, as well as effectively find keywords within the encrypted data

Double-Diffusive Thermo-Solutal Hadley-Prats Flow: Stability Analysis

A mathematical model is developed to study the onset of double-diffusion fluid flow through an infinite permeable channel with internal heat source and viscous dissipation effects under the influence of convection conditions. Darcy's model is utilized for the considered isotropic and homogenous porous medium. A linear instability analysis is conducted and the longitudinal roll disturbances are examined. The dimensionless emerging eigenvalue problem is solved numerically using the fourth order Runge-Kutta scheme for longitudinal roll disturbances. Critical values of wave number and vertical thermal Rayleigh number are determined. A higher value of Gebhart number is observed to correlate significantly with the destabilizing phenomena in Hadley-Prats flow. Concentration based internal heat generation also strongly modifies the critical thermal Rayleigh number. Also, it is found that, the horizontal mass flow and viscous dissipation exert a substantial influence on the onset of instability in the flow regime. Linear instability analysis indicates that, greater values of Lewis number in the porous medium stabilize the convection process for both values of mass diffusion parameter (í µí° ¶ í µí± §). Enhancing í µí° ¶ í µí± § from negative to positive 2 2 values diminishes the critical thermal Rayleigh (í µí± í µí± §) value and consequently induces instability in the porous medium. Increased concentration-based internal heat generation generates the destabilisation process in the flow region. Extensive visualization and interpretation of the solutions relating to the onset of convection are provided. The study is relevant to geothermal, industrial manufacturing and chemical engineering transport processes