Large eddy simulation of structural characteristics in turbulent flow around a circular cylinder close to a wavy wall

The flow characteristics and vortex evolution behind a circular cylinder near wavy wall are studied using large-eddy simulation framework. Reynolds number based on the diameter D is Re = 1500, gap ratio G/ fixed to 1, slope S λ/2 k varies from 2 8 (where G distance between lower surface of crest, λ wavelength, wave amplitude). field characteristics, hydrodynamic coefficients, pressure distributions, evolution, three-dimensional features presented discussed. phase determined by proper orthogonal decomposition, identification method applied capture structures. Compared with smooth wall, changes distribution decreases (increases) mean drag (lift) coefficient. As amplitude increases, Strouhal increases slightly, attaining values 0.25 for 8, 4, 0.26 2. coefficient has an approximately periodic distribution, while friction according secondary vortices wall. Two small appear either side crest before merging into new that moves downstream upper wake vortices. energy first two modes obtained decomposition compared smooth-wall case, whereas third fourth reflecting greater large-scale structures walls. This confirmed examining instantaneous Q-criterion.