Frictional resistance of enclosed rotating cones with superposed throughflow

The research summarized in this paper is an experimental study of the frictional moment on a cone rotating in a conical casing with an outward throughflow. The cone vertex angles tested in the present experiment are theta = 30, 60 and 90 deg. In the region where the frictional moment on the rotating cone with no throughflow is increased by the effect of Taylor-type vortices, an increase of the throughflow rate results in a decrease of the frictional moment, if the throughflow rate is not so large. In the region where the Taylor-type vortices have no appreciable effect on the frictional moment, the rate of increase in C(M) with increasing Cq. sin(theta/2) is almost independent of theta, where C(M) and Cq denote the moment coefficient and the dimensionless throughflow rate, respectively.