Improved delayed detached-eddy simulation and proper orthogonal decomposition analysis of turbulent wake behind a wall-mounted square cylinder
نویسندگان
چکیده
The turbulent flow past a wall-mounted square cylinder with an aspect ratio of 4 was investigated the aid Spalart–Allmaras improved delayed detached-eddy simulation and proper orthogonal decomposition (POD) analysis. Reynolds number equal to 12 000 (based on free-stream velocity obstacle width). boundary layer thickness ∼0.18 height. This study focused analyzing vortical structure wake vortex shedding process along A quantitative comparison first- second-order statistics available experimental direct numerical data used validate results. model coupled method generating inflow conditions could successfully reproduce field around behind commendable accuracy. characteristics near formation region were discussed in detail using time-averaged instantaneous parameters obtained from simulation. Dipole type mean streamwise vortices half-loop hairpin energetic motions identified. coherent reported two-point correlations. Two types intervals identified, namely, low amplitude fluctuations (LAFs) high (HAFs) [P. Sattari et al., Exp. Fluids 52, 1149–1167 (2012)]. HAFs’ interval exhibits von Kármán-like behavior phase difference ∼180°, while LAFs’ shows less periodic behavior. It observed that effect tends weaken alternating POD analysis showed for elevations between 0.25 0.5 height, first two modes represent contribute 66.6%–57.6% total kinetic energy. However, at free end obstacle, have symmetrical nature share 36.5% energy, rest energy is distributed random processes. simple low-order based vortex-shedding angle spectrum time coefficients developed predict dynamics range where dominated.
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ژورنال
عنوان ژورنال: AIP Advances
سال: 2021
ISSN: ['2158-3226']
DOI: https://doi.org/10.1063/5.0045921