Sharif University of Technology Scientia Iranica 1026-3098 24 3 2017 06 01 Effect of alternating magnetic field on unsteady MHD mixed convection and entropy generation of ferro fluid in a linearly heated two-sided cavity 1108 1125 4093 10.24200/sci.2017.4093 EN O. Ghaffarpasand Department of Physics, University of Isfahan, Isfahan, 81746, Iran Journal Article 2015 10 20 This work considers the numerical study of unsteady MHD convection of cobalt-kerosene ferro fluid in a linearly heated two-sided cavity and in the presence of constant and alternating magnetic elds. An accurate nite volume method is adapted to solve the governing equations for this problem. The fluid flow and heat transfer<br />characteristics are studied for a wide range of Richardson numbers (0:01  Ri  10) and Hartmann numbers (0  Ha  100). The volumetric fraction of nanoscale ferromagnetic particles in ferro fluid also varies between 0:0    0:2, while the size of those nanoparticles is fixed at 45 nm. In addition, different alternating magnetic fields with various periods and phase deviations are utilized to study the effect of time-periodic magnetic field on the flow characteristics and heat transfer. The entropy generation and Bejan number are also evaluated to study the eect of key parameters and temporal variation of magnetic field on various fluid irreversibilities. The results show that applying time-periodic magnetic field has remarkably influenced the fluid characteristics, the <br />fluid irreversibilities, and heat transfer within the cavity. Meanwhile, the influence of phase deviation on heat transfer seems to be insignicant. https://scientiairanica.sharif.edu/article_4093_a6b5d9bd363897e6e2838136fe628de1.pdf