Investigation of 2d and 3d Boundary-layer Disturbances for Active Control of Laminar Separation Bubbles
نویسندگان
چکیده
In the present paper mechanisms exploiting hydrodynamic instability of a laminar baseflow in order to control the size of a separation bubble are investigated in detail by means of 2D and 3D direct numerical simulations (DNS). An actuator introduces low amplitude TollmienSchlichting like boundary-layer disturbances into the flow upstream of the bubble, which become amplified and trigger early laminar-turbulent transition of the separated shear flow. In addition to a sinusoidal disturbance type, unsteady signals of shear-stress sensors downstream of the separation bubble are used as feedback input to the actuator. Within these simulations an easy to implement separation-bubble criterion to detect a region of separated flow based on shear stress sensors is used.
منابع مشابه
Active Control of Laminar Separation Bubbles
Control of a transitional laminar separation bubble using steady and unsteady 2D and 3D Tollmien-Schlichting (TS) like boundary-layer disturbances is investigated by means of direct numerical simulations. The specific influence of different disturbance modes which allow an effective reduction of the reverse-flow region is illustrated. It is shown that unsteady 2D or 3D control is more efficient...
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