effect of magnetic field on unsteady natural convection heat transfer of cu– water nanofluid in a square porous cavity

magnetic field effect on unsteady natural convection heat transfer of cu–water nanofluid in a square porous cavity was studied numerically in here. at first, initial temprature of the cavity was and vertical walls were at temprature . suddenly the right wall's tamprature was changed to and the horizontal walls were adiabatic. the effective parameters in this study were ra , ha, and . which appear in the non-dimensionalized equations. ra is a function of temperature difference between hot and cold walls, ha is a parameter that depends on the magnetic field, and is the volume fraction of nano particles. the non-dimensionalized governing equations were obtained based on darcy model. a control volume approach was used for solving these equations. the effect of the variation of parameters, ra , ha and , on heat transfer rate, fluid flow, isotherms, and the steady time of solution were investigated. the solutions show that steady time decreases, as ra increases or decrease. while, variation of ha for high ra has different effects on steady time.