Free Convective Flow of Non-Newtonian Nanofluids in Porous Media with Gyrotactic Microorganism

2015 ◽  
Vol 29 (3) ◽  
pp. 648-648 ◽  
Author(s):  
Md. Jashim Uddin ◽  
W. A. Khan ◽  
A. I. Md. Ismail
Keyword(s):  
Porous Media ◽  
Convective Flow ◽  
Free Convective Flow ◽  
Gyrotactic Microorganism

scholarly journals Unstable Density-Driven Flow in Fractured Porous Media: The Fractured Elder Problem

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 168
Author(s):  
Paiman Shafabakhsh ◽  
Marwan Fahs ◽  
Behzad Ataie-Ashtiani ◽  
Craig T. Simmons
Keyword(s):  
Porous Media ◽  
Convective Flow ◽  
Critical Rayleigh Number ◽  
Fracture Density ◽  
Fracture Networks ◽  
Homogeneous Case ◽  
Free Convective Flow ◽  
Density Driven Flow ◽  
Specific Fracture ◽  
Homogenous Case

The Elder problem is one of the well-known examples of an unstable density-driven flow (DDF) and solute transport in porous media. The goal of this research is to investigate the influence of fracture networks on this benchmark problem due to the great importance of the fractured heterogeneity effect on unstable DDF. For this aim, the fractured Elder problem is solved using COMSOL Multiphysics, which is a finite element method simulator. Uniform and orthogonal fracture networks are embedded to analyze free convective flow and development of unstable salt plumes. The results indicate that the mesh sensitivity of the fractured Elder problem is greater than the homogeneous case. Furthermore, it has been shown that in the fractured cases, the onset of instability and free convection occur with lower critical Rayleigh number, which means that fracture networks have a destabilizing effect. Also, we examined the structural properties of fracture networks that control convective flow patterns, and the simulation results show that the strength of convection and instability at the beginning of the intrusion is proportional to the aperture size of the fractures. Moreover, the increase of the fracture’s density leads different modes of transient convective modes, until a specific fracture density after which the transient convective modes become similar to the homogenous case.

Transient Free Convective Flow of CNT Water Nanofluid with Heat Transfer from a Moving Cylinder

2020 ◽  
Vol 10 ◽  
Author(s):  
C. Sridevi ◽  
A. Sailakumari
Keyword(s):  
Carbon Nanotubes ◽  
Heat Generation ◽  
Convective Flow ◽  
Volume Fraction ◽  
Vertical Cylinder ◽  
Single Wall Carbon Nanotubes ◽  
Free Convective Flow ◽  
Multi Wall Carbon Nanotubes ◽  
Moving Cylinder ◽  
Variable Surface

Background: In this paper, transient two-dimensional laminar boundary layer viscous incompressible free convective flow of water based nanofluid with carbon nanotubes (CNTs) past a moving vertical cylinder with variable surface temperature is studied numerically in the presence of thermal radiation and heat generation. Methods: The prevailing partial differential equations which model the flow with initial and boundary conditions are solved by implicit finite difference method of Crank Nicolson type which is unconditionally stable and convergent. Results: Influence of Grashof number (Gr), nanoparticle volume fraction ( ), heat generation parameter (Q), temperature exponent (m), radiation parameter (N) and time (t) on velocity and temperature profiles are sketched graphically and elaborated comprehensively. Conclusion: Analysis of Nusselt number and Skin friction coefficient are also discussed numerically for both single wall carbon nanotubes (SWCNTs) and multi wall carbon nanotubes (MWCNTs).

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