Iraj Mortazavi home page - Gallery
Research  Interests     CV    Habilitation    Papers    Collaborations    Gallery     Links	- Flow control around a circular cylinder with a porous ring at Re=30000: vorticity fields for the control-off (up) and the porous  (down) cases. A tremendous regularized flow is obtained with the passive control as the flow changes from a chaotic distribution of vortices to a regular Karman street behind the cylinder (Bruneau & Mortazavi JOPE 06). Direct numerical simulations are performed using a multigrid/penalization code.       Without control       With control - Passive control around a square back Ahmed body on the top of a road at Re=30000 with a porous layer in the upper side of the obstacle (direct numerical simulations are performed using a multigrid/penalization code):                           Pressure field:       Without control; average drag coefficient: 0.526       With control; average drag coefficient: 0.332 (-33%) -  Closed-loop active control with two small pulsed jets implemented on the upper and lower parts of a vertical step in a channel flow (Re=2000). The main target of this control technique is to influence directly the vortex shedding and the main recirculation zone: the upper jet changes the shedding dynamics and the lower one perturbates and pushes away the recirculation zone. Computations are performed using high accuracy vortex methods (Creusé et al. 2007, submitted).                                                                           Control with oscilating inlet velocities Sensors for closed-loop control                                                   Control with synthetic or pulsed jets on the step             Averaged streamlines for an uncontrolled flow.             Averaged streamlines for a closed-loop controlled flow with pulsed jets on the step walls.