The characteristics of flow in a cylinder with differentially-rotating split disks is investigated by numerically integrating the unsteady Navier-Stokes equations. Numerical solutions for three configuration of split disks in a cylinder of aspect ratio 0(1) with relatively small Ekman numbers ~O($10^{-4}$) are presented.
First of all, a cylinder with a split disk is considered. According to the difference in angular velocity between the inner portion and the outer portion of a split disk, there occur two secondary flows which have opposite direction and a shear layer of thickness O($E^{1/4}$). It is noted that as the Rossby number increases, the inertial effects are substantial in the flow field. Furthermore, the changes in the flow field by increasing the number of split disks are considered. As the number of split disks increases, the secondary flows become to be very meager. Finally, a cylinder with infinite split disks is considered. When the angular velocity of outer portion is lager than the inner portion at the infinite split disks, a secondary flow which rotate clockwise is observed. When the angular velocity of outer portion is smaller than the inner portion at the infinite split disks, a secondary flow which has counter-clockwise direction occurs.
