Flow analysis of low aspect ratio Taylor-Couette flow by means of particle image velocimetry

Flow measurements and analysis in the low aspect ratio rotating concentric cylinders(Taylor-Couette flow) were performed in terms of the flow structure. Particle image velocimetry was used to obtain the axial and radial velocity fluctuations on a meridional plane of Taylor-Couette flow. In contrast to the high aspect ratio cavity, the waviness of Taylor vortices with lower aspect ratio cavity was suppressed due to the presence of the endwalls, and the critical Reynolds number for the transition from TVF to WVF regime was drastically shifted. Spatial flow structures were extracted by means of proper orthogonal decomposition(POD). Each POD mode characterization enables to understand the governing fluid motion as well as the detailed fluid exchange between two adjacent vortices.