Natural Convection KEY POINTS THIS LECTURE New terms Volumetric thermalexpansion coefficient Grashofnumber Rayleigh number Buoyancy is the driving force Stable versus unstable conditions Nusselt number relationship for laminar free convection on vertical surface Boundary layer impacts: laminar= turbulent Text book sections:$9.1-9.5 Heat Transfer Su Yongkang School of Mechanical EngineeringHeat Transfer Su Yongkang School of Mechanical Engineering # 4 Natural Convection KEY POINTS THIS LECTURE • New terms – Volumetric thermal expansion coefficient – Grashof number – Rayleigh number • Buoyancy is the driving force – Stable versus unstable conditions • Nusselt number relationship for laminar free convection on vertical surface • Boundary layer impacts: laminar  turbulent • Text book sections: §9.1 – 9.5