Begell House Inc.
International Journal of Fluid Mechanics Research
FMR
2152-5102
37
3
2010
Computational Modelling of MHD Flow and Mass Transfer in Stretching Sheet with Slip Effects at the Porous Surface
201-223
Babulal
Talukdar
Department of Mathematics, Gobindapur High School, Murshidabad-742 225, West Bengal, India
Dulal
Pal
Department of Mathematics, Visva-Bharati University Santiniketan, India
This paper presents a perturbation and numerical analysis of the flow and mass transfer characteristics of Newtonian fluid flowing in a horizontal channel with lower side being a stretching sheet and upper being permeable plate bounded by porous medium in presence of transverse magnetic field. The governing nonlinear equations and their associated boundary conditions are first cast into dimensionless forms by a local non-similar transformation. The resulting equations are then solved using perturbation method and the finite difference scheme. Numerical results for flow and concentration distribution and the skin-friction coefficient have been obtained for different values of the governing parameters numerically and their values are presented through table and graphs. The effects of various physical parameters Hartman number, Reynolds number, slip parameter etc. on dimensionless horizontal and vertical velocities and also on mass transfer characteristics are discussed in detail. In particular, the effect of slip velocity at interfacial surface on skin friction factor is found to be more pronounced in a system for higher value of magnetic field. The results also show that the magnetic field parameter has a significant influence on the fluid flow and mass transfer characteristics.
Characterization of Sealing Ring Cavitation in Centrifugal Pumps with Water and Viscous Oil
224-236
K. Gangadharan
Nair
National Institute of Technology Karnataka, Karnataka (St.), India
T. P. Ashok
Babu
National Institute of Technology Karnataka (NITK), Surathkal-575025, India
This research paper presents characterization of sealing ring cavitation in centrifugal pumps with water and viscous oil. The paper discusses development of theoretical formulation for sealing ring cavitation and simulation using software model along with experimental validation. The pump performance test results and its standard clearance for the sealing ring are used to simulate the theoretical model. The study is extended for pumps with SAE−30 lubricating oil. The simulation results present the variation of downstream pressure with different sealing ring dimensions in pumps. The value of downstream pressure determines the possibility of occurrence of cavitation at the clearance. The theoretical formulation developed is validated by using a venturi cavitation test set up. Clearances equivalent to various sealing ring dimensions are made at the test section using different hemispherical models. Theoretical formulation for downstream pressure at the clearance of venturi test section is derived using the test set up details and pump specification. The clearance cavitation coefficients as per K. K. Shelneves equation are obtained from theory as well as from experimentation and compared. The phenomena of cavitation damages the sealing ring which results a fall in performance of the pump. However this research work lead to the prediction of sealing ring cavitation in centrifugal pumps handling water and oil enabling the replacement of sealing ring before affecting cavitation damage.
Thermo-Solutal Convection in Water Isopropanol Mixtures in the Presence of Soret Effect
237-250
Mohammad Azizur
Rahman
Mushroom Research Centre, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur,
Malaysia; Department of Biochemistry and Molecular Biology, Jahangirnagar University, Savar, Dhaka, Bangladesh
M. Ziad
Saghir
Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria St., Toronto, ON M5B2K3, Canada
In the present study, the onset of thermo-solutal convection in a liquid layer overlaying a porous layer where the system is being laterally heated is investigated. The non-linear two-dimensional Navier-Stokes equations, the energy equation, the mass balance equation and the continuity equation are solved for the liquid layer and the Brinkman model is used for the porous layer. The partial differential equations are solved numerically using the finite element technique. Two different cases are analyzed in this study. In the case of the thermo-solutal convection without thermodiffusion or Soret effect, multi-convective cells appear in the liquid layer and as the thickness of the liquid layer decreases (i. e. higher thickness ratio), the flow covers the entire cavity. In the presence of Soret effect, it has been found that the isopropanol component goes either towards the hot or cold walls depending on the Soret sign.
Oscillatory MHD Couette Flow in a Rotating System
251-266
R. R.
Patra
Department of Applied Mathematics, Vidyasagar University, Paschim Medinipur, West Bengal-721102, India
Rabindra N.
Jana
Department of Applied Mathematics, Vidyasagar University, Midnapore-721 102, West Bengal, India
Unsteady oscillatory Couette flow between two infinite horizontal parallel plates in a rotating system has been studied when one of the plate is held at rest and the other oscillates in its own plane. The effects of rotation and frequency parameter on the velocities and the shear stresses for steady and unsteady flow have been studied. It is found that the unsteady shear stress due to primary flow has a phase lag for 2K2 < λ and a phase lead for λ < 2K2 over the plate oscillation. On the other hand, the unsteady shear stress due to secondary flow has a phase lag over the oscillations of the plate either for 2K2 < λ or λ < 2K2, where K2 is the rotation parameter and λ is the frequency parameter.
Analysis of Laminar Flow in a Channel with One Porous Bounding Wall
267-281
Nagendrappa
Bujurke
Karnatak University
Nagaraj N.
Katagi
Department of Mathematics, Manipal Institute of Technology, Manipal University, India
V. B.
Awati
Department of Mathematics, Government Fist Grade College, K. R. Puram, Bangalore-560036, India
Computer extended series solution is used to analyze the problem of laminar flow in a channel with one porous bounding wall. The objective is to study the effect of non-zero tangential slip velocity on the velocity field, pressure gradient and mass transfer. The problem is also studied using power series method in conjunction with an unconstrained optimization procedure. The domain and rate of convergence of the series so generated are further increased by Padé approximants. The coupled diffusion equation in the boundary layer is solved using a finite difference scheme. The solution presented here is valid for much larger Reynolds number compared with earlier investigation.
Flows along a Symmetric Slotted Wedge and Heat Transfer
282-294
Anwar
Hossain
Department of Mathematics, University of Dhaka, Dhaka-1000, Bangladesh
Saleem
Ashgar
Department of Mathematical Sciences, COMSATS Institute of Information Technology, Islamabad, Pakistan
In the present paper the forced convection flow of a viscous incompressible fluid past a uniformly heated slotted wedge has been investigated numerically. The equations governing the flow and heat transfer are reduced to local similarity equations, treating ξ = βx/Rex2, where Re, is the local Reynolds number) as a local slip variable. The transformed boundary-layer equations are solved numerically using implicit finite difference method for all values of ξ in the interval [0,104]. The solutions are also obtained for smaller values of ξ using the perturbation method. Further transformed equations has also been obtained appropriate for large values of ξ, which then have been integrated by the well established local nonsimilarity method. The asymptotic solutions for both smaller and larger values of ξ, obtained in terms of the local skin-friction and local rate of heat transfer for different pressure gradient m, are found in excellent agreement with that obtained by the finite difference solutions for all ξ.