Large-eddy simulation of stably stratified flow past a rectangular cylinder in a channel of finite depth: Fid-Bau Portal

Large-eddy simulation of stably stratified flow past a rectangular cylinder in a channel of finite depth

Dong, Haotian / Cao, Shuyang / Ge, Yaojun

AbstractLarge-eddy simulation is performed to investigate an incompressible stratified flow with a linear temperature gradient past a rectangular cylinder with side ratio $b / h = 0.6$ , where $b$ and $h$ are its breadth and depth, respectively. Simulations are performed for Reynolds number $Re = 8,400$ with respect to a series of stratification numbers $K$ . Results show that transition of stratification effect occurs at around $K = 2$ due to the occurrence of second-order stationary internal waves. Both Strouhal number $St$ and drag coefficient $C_{D}$ decrease with stratification number $K$ when $K < 2$ due to suppression of vertical motion, but increase with $K$ when $K > 2$ because of the stationary internal waves. The relationship between the fields of temperature and other flow parameters are studied and a coincidence of temperature field with internal wave is observed at high stratification number. Finally the stratification effect on the vortex street is discussed.

Highlights•Large-eddy simulation is conducted to study a linearly-temperature-stratified flow past a b/h = 0.6 rectangular cylinder.•A two-stage process is observed in the variation of flow pattern and aerodynamic parameters with stratification number.•A coincidence of temperature field with internal wave occurs at high stratification number.