4230 絞りを有する管内脈動(G05-14 管内流・旋回流,G05 流体工学)  [in Japanese] 4230 A Study on the Pulsating Flow through an Orifice with a Pipe  [in Japanese]

An orifice is widely used for throttling flow in pipes. The flow in pipes used in the industrial plants is found to be mostly unsteady. Under unsteady flow conditions, a knowledge of the detailed flow pattern in the flow field with an orifice in a pipe is needed. In the present paper the flow field downstream of an orifice in a pipe is measured by Laser Doppler anemometry. The experimental results are showed the following: velocity profiles on the centerline of the pipe show hysteresis phenomena when opening area ratio of the rotary valve changes and peak of power spectral density is within potential core region.