  A coupling onset of the cyclone upward and rotation flows is experimentally
demonstrated in a little bottle. The rotating flow provides a pressure increase
in the outer part of the rotating flow by its centrifugal force. When a
gradient of the fluid rotation appears along the rotation axis, the
higher-pressure area is localized and pushes the fluid in a low pressure. Then
the fluid staying in the central area of the rotation is pushed up along the
rotation axis, and the upward wind is enhanced. In this coupling mechanism the
rotation gradient is the key; the coupling of the rotation and the upward fluid
flow is essentially important for a cyclone buildup, and is well explained
experimentally and theoretically.
