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# Grid system on the (ξ, η) plane for case E6L: (a) whole grid; [(b) and (c)] close-ups.

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Large-eddy simulations were used to investigate the supercritical aerodynamics of a square cylinder with rounded corners in comparison with those in the subcritical regime. First, the numerical methods, especially the dynamic mixed model, were validated on the basis of their prediction of supercritical flows past a circular cylinder. Then, the supe...

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Context 1
... measurements. This value is widely used to validate numerical results ( Lehmkuhl et al., 2014;Rodríguez et al., 2015;and Yeon et al., 2016). However, as mentioned before, the accuracy of the measurement by Achenbach (1968) is worth further discussion because of the possible disturbance from the fence probe. Two factors, at least, are notable in Fig. 5 in the work of Achenbach (1968). One is the failure of a separation bubble to form, from the distribution of skin friction at the supercritical Re. The other is the delay of the starting point of the near plateau of the base pressure compared with other experimental and numer- ical studies; that is, the plateau of the base pressure ...
Context 2
... ues in the experiments of Delany andSorensen (1953) andCarassale et al. (2014). The supercritical regime was repre- sented by Re = 1.0 × 10 6 , namely, case E6L, which is higher than Re that causes a dramatic decrease in drag [see the work of Delany and Sorensen (1953)]. Their computational domain and grid system on the (ξ, η) plane are shown in Fig. 5. Case E6L had a spanwise length of L z = 4 that has been demon- strated to be sufficient for the objectives of this study (see the Appendix). The typical subcritical Re = 2.2 × 10 4 was also taken into consideration, namely, case E4. In similar grid topologies, case E4 differed from the supercritical cases only in terms of the grid ...

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## Citations

... Widely studied configurations derived from the square cylinder are various modifications of its corners, for example, rounding (Cao and Tamura 2017), chamfering (Tamura et al. 1998;Tamura and Miyagi 1999), and corner recesses (He et al. 2014). Other variations such as fins, strakes, and shrouds have also been explored (see, e.g., Naudascher et al. 1981). ...
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... For rounded corners, despite the number of studies assessing the large-Reynolds number case (see for e.g. Lamballais, Silvestrini & Laizet 2008Cao & Tamura 2017), few works have considered the dependence of the onset of the instabilities on the corner curvature. Park & Yang (2016) determined, via linear stability analysis, how the primary two-dimensional and the three-dimensional instabilities are affected by rounding the four corners of a rectangular cylinder with AR = 1, exploring the shapes ranging between the square cylinder with sharp edges and the circular cylinder. ...
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... They found that rounding greatly decreases drag and lift forces and at R/D = 0.2 (radius of the corner to the cylinder diameter) the minimum in the mean drag coefficient value is observed. In [8,10] 3D LES are conducted with Re = 4·10 4 and 6·10 5 respectively. Rocchio et al. [8] found that even with smallest corner rounding the agreement with experimental data is better since such rounded corners cause the recirculation bubble at the side faces of the cylinder to be larger, thereby, drag coefficient is decreased. ...
... The drag coefficient attained minima when the angle of incidence was between 5 and 10 degrees. Cao and Tamura [22] simulated subcritical and supercritical flows around square cylinder with a rounded corner ratio r/D = 0.167. Two Reynolds numbers, Re = 2.2 × 10 4 and Re = 1.0 × 10 6 were considered, denoting the subcritical and supercritical regimes, respectively. ...
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