Statistical analyses of a screen cylinder wake. (22nd November 2016)

• Record Type: Journal Article
• Authors: Azmi, Azlin Mohd; Zhou, Tongming; Zhou, Yu; Cheng, Liang
• Is Part Of: Fluid dynamics research. Volume 49:Number 1(2017:Feb.)
• Publication Date: 2016-11-22
• Subjects: vortex shedding -- vortex-induced vibration -- screen shroud; Fluid dynamics -- Periodicals; 620.106
• DOI: 10.1088/0169-5983/49/1/015506
• Languages: English
• ISSNs: 0169-5983

Abstract

Abstract: The evolution of a screen cylinder wake was studied by analysing its statistical properties over a streamwise range of x / d = 10−60 . The screen cylinder was made of a stainless steel screen mesh of 67% porosity. The experiments were conducted in a wind tunnel at a Reynolds number of 7000 using an X-probe. The results were compared with those obtained in the wake generated by a solid cylinder. It was observed that the evolution of the statistics in the wake of the screen cylinder was different from that of a solid cylinder, reflecting the differences in the formation of the organized large-scale vortices in both wakes. The streamwise evolution of the Reynolds stresses, energy spectra and cross-correlation coefficients indicated that there exists a critical location that differentiates the screen cylinder wake into two regions over the measured streamwise range. The formation of the fully formed large-scale vortices was delayed until this critical location. Comparison with existing results for screen strips showed that although the near-wake characteristics and the vortex formation mechanism were similar between the two wake generators, variation in the Strouhal frequencies was observed and the self-preservation states were non-universal, reconfirming the dependence of a wake on its initial condition.