Heat Transfer. 2020;1–18. wileyonlinelibrary.com/journal/htj © 2020 Wiley Periodicals, Inc. | 1 Received: 6 November 2019 | Revised: 18 March 2020 | Accepted: 11 April 2020 DOI: 10.1002/htj.21771 RESEARCH ARTICLE Oscillatory slip f low of Fe 3 O 4 and Al 2 O 3 nanoparticles in a vertical porous channel using Darcy's law with thermal radiation Zaheer Abbas 1 | Sifat Hussain 1 | Muhammad Y. Rafiq 1 | Jafar Hasnain 2 1 Department of Mathematics, Islamia University of Bahawalpur, Bahawalpur, Pakistan 2 Department of Computer Sciences, Bahria University, Islamabad, Pakistan Correspondence Jafar Hasnain, Department of Computer Sciences, Bahria University, Islamabad 44000, Pakistan. Email: jafar_hasnain14@yahoo.com Abstract The heat transfer phenomena and oscillatory flow of an electrically conducting viscous nanofluid (NF) in a channel with porous walls and saturated porous media exposed to the thermal radiation are studied. The nanoparticles (NPs) Fe 3 O 4 and Al 2 O 3 are taken with water as base fluid along with nonuniform temperature and velocity slip at the wall of channel (y′ = 0). The basic laws of momentum and energy conservation are converted into the dimensionless system of the partial differential equations (PDEs) using similarity variables. Closed‐form solutions of these coupled PDEs are constructed for all values of time by taking the oscillatory pressure gradient. The physical insight of involved parameters on the fluid velocity, temperature profile, heat transfer rate, and surface friction is studied and analyzed graphically. It is noted from this study that the fluid velocity shows a decreasing behavior with the volume fraction of NPs. Furthermore, the amplitude of the oscillatory motion in case of skin friction decreases for a large magnetic field. KEYWORDS nanofluid, oscillatory flow, slip condition, thermal radiation, vertical porous channel