Volumetric flow measurements using

Particle Image Velocimetry

Dr. Lian Gan

（Durham University, UK）

时间：2017年8月11日（周五）上午10:00

地点：中国科学院力学研究所1号楼312会议室

Abstract:

In this talk, two volumetric particle Image Velocimetry (PIV) techniques will be discussed via the data obtained from the measurements of two types of turbulent flows. The first technique uses passive scanning stereoPIV (based on Taylor Hypothesis) to reconstruct a fully 3D turbulent vortex ring. The second technique uses our in-house developed TomoPIV package to capture the coherent enstrophy structures in a locally isotropic turbulent field; see Fig 1. The two methods are both able to resolve the complete velocity gradient tensor, but they have their advantages in different applications. Stereo-scanning PIV is a quasi-instantaneous technique but generally has higher spatial resolution. TomoPIV is truly instantaneous and hence can resolve temporal derivatives. However, it has significant hardware requirements and is not suitable for high seeding conditions. In the talk, comparison of the two techniques will be briefly discussed through the assessment of divergence of the 3D velocity fields. 

Fig.1 (a) A turbulent vortex ring; (b) Coherent structures in a locally isotropic turbulence.

Biography:

Dr. Lian Gan (干联) is an assistant professor of fluid mechanics at Durham University, UK. He obtained his MEng degree from Mechanical Engineering, National University of Singapore, specialised in aeronautics, under the full-scholarship scheme for students from China. He obtained his PhD degree from University of Cambridge Engineering fluid mechanics group on experimental investigation of turbulent vortex rings. His research interests and speciality are in experimental study of turbulence and vortex dynamics, using Particle Image Velocimetry (from 2DPIV to TomoPIV). Recently his research interest extends to applications in human cardiac fluid dynamics.