抄録
Turbulent channel flows with several different types of rectangle riblets are investigated by means of the direct numerical simulation (DNS). The slow field in the cases of the wide and deep riblets is unstable and the two pairs of the secondary flow vorticities appear around a riblet. On the other hand, that in the narrow and shallow riblets is stable the same as the turbulent channel flow without riblets and spontaneous structures does not get into the riblet ravines.
