Three-dimensional numerical simulation of conjugate heat transfer in a microchannel involving harmonic rotating longitudinal vortex generators is performed. The Al2O3–water nanofluid with concentration of 0.5% of volume fraction is
used. The mean diameter of particles is 29 nm. The Nusselt number and Fanning friction factor of the microchannel
changes are investigated for different Reynolds numbers, rotation frequency, and rotation’s direction. Results show that
time variations of Nusselt number and friction factor are periodic and their frequencies are the same as vortex generator’s
rotation frequencies. It was observed that the amplitude of Nusselt number increases with increasing Reynolds number.
Furthermore, when all the vortex generators are rotating in the same direction, the amplitudes of Nusselt number and
friction factor are higher than when they are rotating in opposite directions