Local nonsimilarity solutions for mixed convection boundary layer flow of a micropolar fluid on horizontal flat plates with variable surface temperature

摘要

An analysis is performed to study the heat transfer characteristics of laminar mixed convection boundary layer flow of a micropolar fluid over a semi-infinite horizontal flat plate with nonuniform surface temperatures. The surface temperature is assumed to vary as a power of the axial coordinate measured from the leading edge of the plate. A nonsimilar mixed convection parameter ξ and a pseudo-similarity variable η are introduced to cast the governing boundary layer equations into a system of dimensionless equations which are solved numerically using finite difference method. The mixed convection parameter is chosen to cover the entire regime of mixed convection from the pure forced convection limit to the pure free convection limit. The effect of material parameter, the exponent for the power-law variation in wall temperature and the nonsimilar mixed convection parameter are considered. The micropolar fluids are observed to display drag reduction and reduce surface heat transfer rate when compared to Newtonian fluid. The effect of the buoyancy force results in the enhancements of friction factor, heat transfer rate and wall couple stress. The local heat transfer rate is found to increase with increase in the exponent value of the power-low variation in wall temperature.