Tomographic-imaging 기술을 이용한 연성 필름이 부착된 실린더의 후류 및 연성 필름 운동 동시계측

Abstract

Simultaneous Measurements of the Wake Flow of a Circular Cylinder with a Flexible Film and Its Motions using Tomographic Imaging Technique

by Seong yong, Kwon

Department of Refrigeration and Air-Conditioning Engineering

Graduate School of Korea Maritime University

Abstract

Many engineers have tried to analyze the interactions between fluid flows and structures motions. In order to understand the flow-structure interaction(FSI), the energy given by the fluid to the structure should be evaluated, and the energy given by the structure's motion or vibration to the fluid should also be evaluated. To do this, the vector field of the fluid should be measured, and the motion of the structure should be measured, simultaneously. Since the flow fields are generally strong three-dimensional, the measurement for the flow field should be made in three dimension.

There have been many techniques for three-dimensional measurements, such as 3D-PTV, Stereoscopic PIV, Holographic-PIV, and Tomographic PIV. Among them, the Tomographic PIV is widely focused nowadays for its measurement performances for three-dimensional flows. This allowed researchers to measure three-dimensional flow motion with high resolution. However, the demerit of this technique was the filtering effect coming from the PIV principle. This implies that the small vortices were apt to be filtered out by the interrogation window of PIV, and detailed structures were easily unmeasurable. In order to overcome this drawback, a Tomographic-PTV based technique is introduced in this study. With the constructed Tomographic-PTV technique, the wake flow of a cylinder body with a flexible film was measured, and simultaneously the motion of the film was measured.

The film is made of Loden with configurations of 35mm(W) * 100mm(L) * 0.024(T). This was attached on to a cylinder (d=30mm). The Reynolds number tested was 2447. The measurement system consists of an Ar-ion laser(8W), a high speed camera(1024*992pixel, 200fps) and a host computer. The interactions between the wake flow and the film motion were investigated with the measured results.