Study of buoyant force acting on different fluids moving over a horizontal plate due to forced convection

Abstract

In this paper, the effect of buoyancy force on heat transfer over flat plate due to forced convection is investigated numerically. The governing equations namely continuity, Navier-stokes and energy equations were discretized by using an explicit finite difference technique. Code generation has been done in FORTRAN-95 programming language. The testing of FORTRAN code has been done for different fluids at different grid points. The length of horizontal flat plate (x) was taken as 0.5 m. The inlet velocity of fluid (u) at the edge of plate was taken as 3 m/s. The kinematic viscosity (υ) of air and water at 323 K were taken as 17×10-6 m2/s and 66×10-7 m2/s respectively. The surface temperature (Ts) of plate and flow temperature (To) of fluid were taken as 300 K and 323 K respectively. The grid was discretized by continuous method into 1001×101 (m×n) mesh points. The results show the boundary layer thickness, velocity and temperature evolutions, and heat transfer coefficient formed by different fluids. Also, the heat transfer coefficient to surrounding fluid across flat plate was found higher for air as compared to water. Results showed that buoyancy force acts from downward position so it was observed maximum at lower distance of plate. However, buoyancy effect reduces as the distance of x increases.