BUKU ABSTRAK - Universiti Putra Malaysia

Science, Technology & Engineering
MHD Mixed Convection Flow Near the Stagnation-point on a Vertical Permeable
Surface
Mrs. Norfifah Bachok
Anuar Ishak, Roslinda Nazar and Norazak Senu
Institute of Mathematical Research, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 6849; norfifah@fsas.upm.edu.my
To investigate the steady magnetohydrodynamic (MHD) mixed convection boundary layer flow of a viscous
and electrically conducting fluid near the stagnation-point on a vertical permeable surface. The effects of suction
as well as magnetic parameter near the stagnation-point are studied. A similarity transformation is used to reduce
the governing partial differential equations to a set of nonlinear ordinary differential equations which are then
solved numerically using a finite-difference method. The dual solutions exist for both assisting and opposing
flows. The range of the mixed convection parameter for which the solution that exists, increases with suction.
The solutions can be obtained up to a certain value of the moving parameter (critical value or turning point).
The boundary layer separates from the plate beyond the turning point hence it is not possible to get the solution
based on the boundary layer approximations after this point. To obtain further solutions, the full Navier-Stokes
equations have to be solved. The flow due to a permeable surface is relevant to several practical applications in
the engineering activities such as in the design of thrust bearing and radial diffusers, and thermal oil recovery. In
these cases, the properties of the final product depend to a great extent on the rate of cooling which is governed
by the structure of the boundary layer near the permeable surface. The present results are original and new for
the boundary layer flow of a viscous and electrically conducting fluid near the stagnation-point on a vertical
permeable surface. Therefore this study would be important for the scientists and engineers in order to become
familiar with the flow behaviour and properties of such permeable surface, and the way to predict the properties
of this flow for the process equipments.
Keywords: MHD, mixed convection, suction/injection, dual solutions, stagnation-point
Melting Heat Transfer in Steady Laminar Flow over a Moving Surface
Mrs. Norfifah Bachok
Anuar Ishak, Roslinda Nazar and Norazak Senu
Faculty of Science, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 6849; norfifah@fsas.upm.edu.my
To investigate the steady laminar boundary layer flow and heat transfer from a warm, laminar liquid flow to a
melting surface moving parallel to a constant free stream. The effects of the melting parameter, moving parameter
and Prandtl number on the flow and heat transfer characteristics are studied. A similarity transformation is used
to reduce the governing partial differential equations to a set of nonlinear ordinary differential equations which
are then solved numerically using the Runge-Kutta-Fehlberg method. There is a region of unique solutions for
moving parameter, however, multiple (dual) solutions exist when the solid surface and the free stream move in
the opposite directions. The solutions can be obtained up to a certain value of the moving parameter (critical value
or turning point). The boundary layer separates from the plate beyond the turning point hence it is not possible
to get the solution based on the boundary layer approximations after this point. To obtain further solutions, the
full Navier-Stokes equations have to be solved. The flow due to a moving flat plate is relevant to several practical
applications in the field of metallurgy, chemical engineering, etc. For example in magma solidification, melting of
permafrost and preparation of semiconductor materials. In these cases, the properties of the final product depend
to a great extent on the rate of cooling which is governed by the structure of the boundary layer near the melting
surface. The present results are original and new for the boundary layer flow and heat transfer for a melting
surface moving parallel to a constant free stream. Therefore this study would be important for the scientists and
engineers in order to become familiar with the flow behaviour and properties of such melting surface.
Keywords: Melting, heat transfer, steady, dual solutions, moving surface
230