ferrofluid injection and applied magnetic field influences on the characteristics of flow over a cylinder

The present article presents an innovative method to reduce drag in flow over a cylinder by using kelvin force. in contrast to the previous works, there is no need to move or additional geometry parts. for this purpose,  nanofluid is injected from gaps embedded over the circular cylinder surface. moreover, the heat transfer rate has been evaluated over the rigidly fixed cylinder surface. in this study, flow and heat transfer characteristics are investigated by the open-source code of openfoam, under the effect of the induced magnetic field of a single electric current carrier wire. the modified model of buongiorno that contains the magnetophoresis term is utilized for the two-phase modeling of ferrofluid flow. for discretization of the governing unsteady equations including conservation laws of mass, volume fraction transport, and momentum equations that contain the ferro-hydrodynamics force as a source term, the finite volume method, and piso algorithm are considered. the drag coefficient, entropy generation, nusselt number, streamlines, and temperature contours are computed for three reynolds numbers of 120,150, and 180. it is obtained that, the presence of the magnetic field at various volume fractions has significant effects on these parameters. for instance, by increasing the magnetic intensity (b) from 0 to 0.002 t, the pressure drag coefficient, the total entropy generation, and the nusselt number are reduced by about 153%, 11.76%, and 17.24%, respectively.