U字管内の脈動流れ

抄録

A pulsating flow has been studied experimentally, because of its practical importance in mechanical engineering. It is very useful to investigate such an unsteady flow experimentally for the improvement of efficiency of many mechanical apparatus. The purpose of this experiment is to clarify effects of the pipe length of the upstream straight part on its flow behavior. We measured the wall static pressure and velocity distributions of the axial flow, respectively. Phase delay can be seen in the unsteady behavior of the pressure. As a result of the measurement of the axial velocity distribution, there is little difference in the unsteady behavior of the axial velocity distribution until the valve is fully closed, regardless of the length of the upstream straight part. However, when extending the upstream straight part, the flow starts in the inside portion of pipe immediately after the valve is opened.