Top: representation of a vertical slice (y, z-plane) in the observed upflow region of the domain, showing the vertical flow speeds of ±8 km s^-1. Middle: the same but for a horizontal plane (x, y plane inside the corona). Bottom: time slice of the density variation in height, showing how structures are moving upward in the atmosphere with a speed of roughly 150 km s^-1. The plot also show the period of the oscillations is of the order of 3.7 min. The snapshots used for the top and middle frames represent t = 132.5 min.