LES Investigation of Passive Flow Control Around an Ahmed Body

Paper in proceeding, 2013

Large eddy simulations are used to study passive flow con- trol for drag reduction in a simplified ground vehicle. Add on devices in the form of short cylinders are used for the forma- tion of streaks in the streamwise direction that lead to the sep- aration delay. The results of the present numerical simulations are compared with the experimental data and show good agree- ment. The two-stage flow control mechanism is analyzed from the LES results. It was found to be in agreement with the previ- ous experimental observations that the counter-rotating vortices behind the impinging devices influence the separation only indi- rectly through the longitudinal vortices further downstream.