Natural convection along a vertical complex wavy surface

A previously proposed transformation has been applied to the natural-convection boundary layer along a complex vertical surface created from two sinusoidal functions, a fundamental wave and its first harmonic. The numerical results demonstrate that the additional harmonic substantially alters the flow field and temperature distribution near the surface. The conclusion that the averaged heat-transfer rate per unit-wetted wavy surface is less than that of a corresponding flat plate [L.S. Yao, Natural convection along a vertical wavy surface, ASME J. Heat Transfer 105 (1983) 465–468] has been confirmed for this more complex surface. On the other hand, the total heat-transfer rates for a complex surface are greater than that of a flat plate. The numerical results show that the enhanced total heat-transfer rate seems to depend on the ratio of amplitude and wavelength of a surface.