  We present a study of three highly non-radial solar wind events when the
azimuthal solar wind flow angle exceeds > 6 degrees for one day or more. None
of the events are associated with coronal mass ejections and co-rotating
interaction regions observed at 1 AU. For all events, the solar wind outflows
at 1 AU have low solar wind velocity and solar wind density. Based on the
significant increase in the Oxygen charge state ratio of O7+/O6+ at 1 AU for
all of the events, we have traced them back to the Sun and found that their
source regions originated in an active region and coronal hole (AR-CH) pairs
mainly located at the central meridian. Further, examining the dynamical
evolutions in their source regions using both the Extreme ultra-violet Imaging
Telescope and Michelson Doppler Imager, it is found that the changes taking
place in AR-CH boundaries eventually disturbed the stable CH configurations,
resulting in a reduction of the CH area and finally its disappearance, leaving
only with the AR. Our study provides a possible explanation to discuss the
origin of the prolonged and highly non-radial solar wind flows.
