Sains Malaysiana 40(10)(2011): 1193–1199

MHD Stagnation-Point Flow towards a Stretching Sheet with

Prescribed Surface Heat Flux

(Aliran Titik Genangan MHD terhadap Helaian Meregang dengan Fluks Haba Permukaan Ditetapkan)

Anuar Ishak* & R. Nazar

School of Mathematical Sciences, Universiti Kebangsaan Malaysia, 43600 UKM Bangi

Selangor, Malaysia

Norihan M. Arifin & Fadzilah M. Ali

Department of Mathematics, Faculty of Science, Universiti Putra Malaysia

43400 UPM Serdang, Selangor, Malaysia

I. Pop

Faculty of Mathematics, University of Cluj, R-3400 Cluj, CP 253, Romania

Received: 15 July 2010/Accepted: 6 September 2010

ABSTRACT

The steady two-dimensional stagnation point flow of an incompressible viscous and electrically conducting fluid, subject to a transverse uniform magnetic field, towards a stretching sheet is investigated. The governing system of partial differential equations are transformed to ordinary differential equations, which are then solved numerically using a finite difference scheme known as the Keller-box method. The effects of the governing parameters on the flow field and heat transfer characteristics are obtained and discussed. It is found that the heat transfer rate at the surface increases with the magnetic parameter when the free stream velocity exceeds the stretching velocity, i.e. ε>1, and the opposite is observed when ε<1.

Keywords: Heat transfer; magnetohydrodynamic; stagnation point flow; stretching surface

ABSTRAK

Aliran titik genangan mantap dua matra bagi bendalir likat tak termampatkan dan pengkonduksi elektrik terhadap helaian meregang tertakluk kepada medan magnet melintang seragam diselidik. Sistem menakluk persamaan pembezaan separa dijelmakan kepada persamaan pembezaan biasa, yang kemudiannya diselesaikan secara berangka menggunakan skim beza terhingga dikenali sebagai kaedah kotak Keller. Kesan parameter-parameter menakluk terhadap medan aliran dan ciri-ciri pemindahan haba diperoleh dan dibincangkan. Didapati bahawa kadar pemindahan haba pada permukaan meningkat dengan peningkatan parameter magnet apabila halaju aliran bebas melebihi halaju regangan, iaitu ε>1, dan keputusan yang bertentangan diperhatikan apabila ε<1.

Kata kunci: Aliran titik genangan; magnetohidrodinamik; pemindahan haba; permukaan meregang

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*Corresponding author; e-mail: anuarishak@yahoo.com