Unsteady transient slip flow of Williamson nanofluid containing gyrotactic microorganism and activation energy

Owing to the magnified thermal performances of nanoparticles and essential applications in various industrial and engineering processes like heat exchangers, cooling systems, boilers, MEMS, chemical engineering, laser diode arrays and cool automobile engines, variety of research is presented in this topic. On this end, current investigation deals with the unsteady flow of Williamson nanofluid containing the gyrotactic microorganisms over a rotating cylinder. The additional features like activation energy, chemical reaction and variable thermal conductivity are also composed in the current flow problem. The whole flow model is subjected to the second order slip from which results two slip parameters that effectively control the associated boundary layers. The formulated problem is based on the utilization of governing equations which are converted into dimensionless form with help of appropriate transformation. The self similar solution of constituted equations is followed by using shooting technique. The obtained results are confirmed by comparing already reported investigations with convincible agreement. The graphical analysis for involved parameters is comprehensively presented for both circular cylinder and flat plat as a liming case. The physical aspects of each flow parameter are discussed. The numerical illustration for local Nusselt number, local Sherwood number and motile density number are also presented in tabular form. The results show that temperature ratio parameter and slip constant increase the nanofluid temperature which is more prominent in case of circular cylinder. The concentration and microorganism distributions enhances with unsteady parameter. Moreover, a declining microorganism distribution is observed with mixed convection parameter, Peclet number and bioconvection Lewis number. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of Faculty of Engineering, Alexandria University.