Sains Malaysiana 39(4)(2010): 671–676

Aliran Lapisan Sempadan Olakan Bebas Terhadap Silinder  Bulat Mengufuk dengan Pemanasan Newtonan

(Free Convection Boundary Layer Flow over a Horizontal Circular  Cylinder with Newtonian Heating)

Mohd Zuki Salleh

Fakulti Sains dan Teknologi Industri, Universiti Malaysia Pahang

Lebuhraya Tun Abdul Razak, 26300 UMP Kuantan, Pahang, Malaysia

Roslinda Nazar*

Pusat Pengajian Sains Matematik, Fakulti Sains dan Teknologi

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

Diserahkan: 13 Ogos 2009 / Diterima: 26 Oktober 2009

ABSTRAK

Penyelesaian berangka bagi masalah aliran lapisan sempadan olakan bebas mantap terhadap silinder bulat mengufuk yang dijanakan oleh pemanasan Newtonan, iaitu pemindahan haba dari permukaan berkadar langsung dengan suhu permukaan setempat, dipertimbangkan. Persamaan lapisan sempadan terjelma diselesaikan secara berangka dengan suatu skim berangka beza terhingga tersirat yang dikenali sebagai kaedah kotak Keller. Penyelesaian berangka diperoleh bagi pekali geseran kulit, pekali pemindahan haba setempat, suhu dinding serta profil halaju dan suhu. Ciri-ciri aliran dan pemindahan haba bagi suatu julat nilai nombor Prandtl yang besar dianalisis dan dibincangkan.

Kata kunci: Lapisan sempadan; olakan bebas; pemanasan Newtonan; silinder bulat mengufuk

ABSTRACT

The numerical solution of steady free convection boundary layer flow over a horizontal circular cylinder, generated by Newtonian heating in which the heat transfer from the surface is proportional to the local surface temperature, is considered. The transformed boundary layer equations are solved numerically using an implicit finite-difference numerical scheme known as the Keller-box method. Numerical solutions are obtained for the skin friction coefficient, local heat transfer coefficient, wall temperature as well as the velocity and temperature profiles. The features of the flow and heat transfer characteristics for large range of values of the Prandtl number are analyzed and discussed.

Keywords: Boundary layer; free convection; horizontal circular cylinder; Newtonian heating

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*Pengarang untuk surat-menyurat; email: rmn@ukm.my