After a narrow channel region, small flowing particles make
a turn: they switch from an alignment parallel to the flow direction to a
perpendicular alignment. This surprising behavior was discovered by a group of
international researchers, among them Dr. Julian Thiele from the Radboud
University Nijmegen. They published their results on April 8 in the Online
early edition of PNAS (Proceedings of the National Academy of Sciences of the
United States of America).