There are many needs for measuring air flow velocity and direction under the air flow with water drops. For example they are the measurement of air flow velocity and direction in weather observations, the measurement of side wind in a car and a small ship, and so on. However it is difficult to measure the air flow velocity and direction under the air flow with water drops with high accuracy. In this paper we clarified that the measurement of the air flow direction is possible under the air flow with water drops by measuring negative pressure in the back of column in the interference flow around another columns, the measurement of the air flow velocity is possible under the air flow with water drops by measuring negative pressure in the cylinder.
The energy storage systems are needed in order to level off daily fluctuations of loads on electric power, because of increasing electric power demands. A flywheel energy storage system (FESS) is believed to be one of potential systems. FESS was difficult to store energy for long time. This reason was that they were equipped with ball bearings induced higher energy loss. In the present investigation, the flywheel rotor is supported by active magnetic bearings (AMB) to enable the rotation stable at higher speed with lower mechanical loss. In order to develop the AMB of extremely low loss, the energy loss of the AMB is measured by using a test rig. Results obtained by free-running tests show the energy loss of the homopo-lar AMB is smaller than that of the heteropolar AMB. And we show that we can reduce the energy loss of AMB by apply-ing non-linear zero power control method.
A fluid coupling of variable capacity type can attain continuous change of rotational speed by changing the fluid capacity. It is widely used, but the flow characteristics and torque curve is not understood yet. In our experiment, the torque curve shows some unstableness. In some cases the transmitted torque is reduced very slowly for over 10 minutes. In other cases the torque and rotational speed of output shaft becomes unsteady. We found that the length of partition plate affects the former instability by viewing the flow near the balance hole. The plate controls the flow quantity from the balance hole, and the fluid capacity in the coupling is changed by this flow. The flow behind the coupling affects the transmitted torque viathis flow.