Begell House Inc.
International Journal of Fluid Mechanics Research
FMR
2152-5102
42
5
2015
Effect of Suspended Particles on the Onset of Thermal Convection in a Nanofluid Layer for More Realistic Boundary Conditions
375-390
Ramesh
Chand
Department of Mathematics, Government Degree College Sugh-Bhatoli, Himachal Pradesh,
India
G. C.
Rana
Department of Mathematics, Government College Hamirpur, Himachal Pradesh, India
Ahmed Kadhim
Hussein
College of Engineering, Mechanical Engineering Department, Babylon University, Babylon City, Hilla, Iraq
The effect of suspended particles on the onset of thermal convection in a horizontal layer of nanofluid is studied. The flux of volume fraction of a nanoparticle is taken to be zero on the isothermal boundaries. The model used incorporates the effect of Brownian diffusion and thermophoresis. The relevant equations of the problem are linearized using Boussinesq approximation and the perturbed quantities are analyzed in terms of normal modes analysis. The stability criterions for stationary and oscillatory convection have been derived and graphs have been plotted to study the effects of the suspended particles, Lewis number and modified diffusivity ratio on the stationary convection and it is found that suspended particle, Lewis number and modified diffusivity ratio destabilizes fluid layer.
On arresting the Complex Growth Rates in Magnetohydrodynamic Triply Diffusive Convection
391-403
Jyoti
Prakash
Department of Mathematics and Statistics, Himachal Pradesh University, Summer Hill,
Shimla-171005, India
Kanu
Vaid
Department of Mathematics and Statistics, Himachal Pradesh University Summer Hill, Shimla-171005, India
Renu
Bala
Department of Mathematics and Statistics, Himachal Pradesh University Summer Hill, Shimla-171005, India
The paper mathematically establishes that the complex growth rate (pr ,pi) of an arbitrary neutral or unstable oscillatory perturbation of growing amplitude, in a magneto triply diffusive fluid layer with one of the components as heat with diffusivity κ must lie inside a semicircle in the right half of the (pr,pi) plane whose centre is origin and radius is max[√((R1 + R2)σ), Qσ], where R1 and R2 are the Rayleigh numbers for the two concentration components with diffusivities κ1 and κ2 (with no loss of generality κ > κ1 > κ2), Q is the Chandrasekhar number and σ is the thermal Prandtl number. It is further proved that the above result is uniformly valid for any combination of rigid and free boundaries (which may be insulating or perfectly conducting).
Comprehensive Analytical Study of Rarefied Jet Flow of Annular Exit Impingement at Vertical Flat Plate
404-417
Khaleel R.
Al Khasawneh
Department of Mechanical Engineering, Jordan University of Science and Technology, Irbid
Chunpei
Cai
Department of Mechanical and Aerospace Engineering, New Mexico State University Las Cruces, New Mexico, USA, 88003
Mohammad
Al Tarawneh
Department of Mechanical Engineering, The Hashemite University Jordan
A rarefied gas flowing out of an annular exit and impinging at a vertical flat plate was studied theoretically at the free molecular flow limit. Several analytical expressions of collisionless flow property's distributions on the plate surface were obtained by employing a constraint relation about the velocity components of gas particles leaving a nozzle of annular exit and arriving at a given spatial point outside the nozzle. These flow property distributions include density, slip velocity, temperature, pressure, shear stress, force on the plate, and heat flux. Simplified analytical results were provided and compared with the numerical results obtained by the direct simulation Monte Carlo method. In general, the exact analytical solutions and the numerical ones are virtually identical.
Comparison of Kinematics of Horseshoe Vortex at a Flat Plate and Different Shaped Piers
418-448
Subhasish
Das
School of Water Resources Engineering, Jadavpur University, Kolkata, West Bengal, India
Asis
Mazumdar
School of Water Resources Engineering, Jadavpur University, Kolkata 700032, India
This paper presents an experimental investigation on the kinematics of horseshoe vortex around a flat plate. In order to have a comparative study, the velocity measurements within clear water equilibrium scour hole at circular, square, and equilateral triangular piers of sides equaling the width of the flat plate are also taken by an acoustic Doppler velocimeter. The contours and spatial distributions of the time-averaged (mean) velocities, turbulence intensities and turbulent kinetic energy at different azimuthal planes (0° that is at the upstream axis of symmetry, 45, and 90°) were deduced. Velocity vector plots of the flow field at azimuthal planes were used to show further flow features. The vorticity and circulation of the horseshoe vortex were determined by using forward difference technique of computational hydrodynamics and Stokes theorem, respectively. The horseshoe vortex flow and turbulence characteristics were discussed from the standpoint of similarity with velocity and turbulence intensity characteristic scales.
Numerical Investigation of New Alternative Nador Lagoon Inlet Relocation
449-462
Mohammed
Jeyar
Laboratoire de Mecanique et Energetique, Faculte des Sciences Oujda Morocco
Elmiloud
Chaabelasri
Laboratoire de Mecanique et Energetique, Faculte des Sciences Oujda Morocco
Najim
Salhi
Laboratoire de Mecanique et Energetique, Faculte des Sciences Oujda Morocco
In this work, new alternative inlet relocation has been investigated using 2D hydrodynamic and transport models to the Nador lagoon (Morocco), a coastal system connected to the sea through a narrow and shallow inlet. The model is based on the finite volume method. It solves the shallow water equations on a spatial domain that represents the whole lagoon basin. The current inlet was artificially opened and an alternative inlet was relocated into a southward position. This work investigates the hydrodynamic patterns and the potential pathways of tracers in Nador lagoon in two distinct configurations: before and after inlet relocation. The hydrodynamic model was successfully calibrated and validated against observed elevations, accurately reproducing the tidal propagation. The inlet relocation increases the magnitude of tidal currents, suggesting a better water circulation. The tracers transport simulations suggest enhanced water exchanges through the lagoon inlet and smaller residence times in the central part of basin with the alternative configuration. Overall, it is concluded that the inlet relocation had a positive contribution towards increasing the water renewal of the whole lagoon, thus decreasing its vulnerability to pollution.