Flow structure in the downstream of square and circular cylinders

Quantitative flow characteristics for side-by-side square cylinders via PIV

“…Regarding the onset and development of small-scale vortical structures in the separating shear layer, regions of low-level vorticity concentrations are detectable in the pattern of instantaneous vorticity ǔ for all patterns in the first row of Figure 2 and in the first column of Figure 3. Large-scale Von Kármán vortices form in the near-wake region due to the abrupt coalescence of small-scale shear-layer vortices that developed along the separating shear layers similar to the results of Ozgoren (2006). Instantaneous vorticity patterns ǔ show irregular distributions, and the shear layers tend to break up easily into small concentrations of vorticity ǔ related to Kelvin-Helmholtz (KH) instabilities.…”

“…They stated that although the overall flow structure past the SC resembled that of the CC, there were major differences as far as the separation mechanism and the related integral parameters such as Strouhal number, lift and drag-coefficient concerned. Ozgoren (2006) visualized flow characteristics quantitatively in the downstream region of the single circular, sharp-edged square and 45 o orientated SC in a uniform flow using PIV [6]. Many interesting and unexpected fluid phenomena may occur when two or more bluff bodies are placed one beside the other as reported by Zdravkovich [7] and Williamson [1].…”

“…Reynolds stress contours for the SC have peak value of 0.132. For further details, researcher should refer to Ozgoren [6] who has investigated detailed studies of the flow structures in the downstream of single circular, square and oriented square cylinders. The time-averaged patterns of streamline patterns <\> is interpreted in terms of foci, F, and saddle points, S as displayed in the second row of Figure 2.…”

“…For this reason, aerodynamic forces acting on the two or three structures could be very different in comparison with a single structure [1]. A large number of studies have been performed to investigate the flow characteristics of single SC and circular cylinder (CC) [1][2][3][4][5][6]. Okajima (1982) carried out an experimental study of flow past a SC as well as rectangular cylinder for 70 Re 20,000 to determine the vortex shedding frequencies.…”

Experimental and Numerical Investigation of Flow Structures around Cylindrical Bluff Bodies

“…When fluid flows around any bluff body, the vortices are alternatively shed and a well-known Karman vortex street is formed in the wake of the cylinder, which can cause structural damage as a result of regular and irregular surface loading [1].…”