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 θ = 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, on the other hand, the rate of increase in C_M with increasing Cq. sin (θ/2) is almost independent of θ, where C_M and Cq denote the moment coefficient and the dimensionless throughflow rate, respectively.