Unsteady unidirectional MHD flows of a non‐Newtonian fluid saturated in a porous medium

Abstract

Some exact solutions for unsteady unidirectional MHD flows of a class of non‐Newtonian fluid saturated in a porous medium are obtained, including flows driven by oscillating pressure gradient, oscillating surfaces in their own planes, suddenly started surfaces, and so on. Besides, the frictional forces on the surfaces are also studied. Generally the flow is retarded by the effects of both the magnetic field and the presence of a porous medium; however, the effect of viscoelasticity of the second grade fluid on the flow behavior is rather complicated. This study is essentially an extension of work by Rajagopal (1982) and Hayat et al. (2000).

Key words:

• non‐Newtonian fluid
• unsteady unidirectional flow
• MHD flow
• porous medium

Notes

I. C. Liu is with the Department of Civil Engineering, National Chi Nan University, Nantou, Taiwan 545, R.O.C. (Tel: [phone]; Fax: [phone]; Email: [email protected])