Abstract
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.
