Kenichi Tezuka

TL;DR: In this article, experimental and numerical investigations are conducted using rigid and flexible valve head supports to clarify the mechanisms of valve head vibrations that are caused by unsteady flows around the valve.

TL;DR: In this article, the authors investigated the valve instability that is responsible for large vibrations in a steam control valve and found that a complex three-dimensional (3D) flow structure (valve-attached flow) sets up in the valve region leading to a high pressure region on a part of the valve body.

TL;DR: In this paper, an ultrasonic pulse Doppler flow meter was used to measure velocity profiles in a steel penstock with a diameter of over one meter and Reynolds number of more than five million, and two transducers were placed on the pipe surface to validate the multi-line measurement of asymmetric flow.

TL;DR: In this article, the velocity profile of the flow in a pipe and its influence on the profile factor used with conventional flow meters were investigated with ultrasonic pulse Doppler measurements, from the measured velocity profiles, the influences of surface roughness and Reynolds number were characterized qualitatively and quantitatively.

TL;DR: In this article, a technique for more accurate flowrate measurement by allowing transmission in both a wedge and a pipe wall and measuring flowrate more accurately is provided. But the ultrasonic transmitting/receiving unit is of a clamp-on type and the distance from ultrasonic transmission means of a wedge to the outer wall of the fluid pipe and fluid pipe thickness satisfy the condition that they are both integral multiples of λ/2 of the use frequency.