Synthetic jets are zero-net mass flux flows that have been recently used in a wide range of flow control applications, among which the control of bluff body wakes. An optimal control is based on an appropriate tuning of the involved parameters, which implies knowledge of the effects of such parameters on the flow field. The present work reports on an experimental investigation of the active open-loop control of a cylinder wake at Reynolds number equal to 4980 using a slot synthetic jet located at the rear stagnation point. Three values of f+ (0.48, 0.96 and 1.92) are considered and, for each of them, Cµ is varied among as many different values (4.6%, 9.3% and 18.5%). The flow field in the cylinder wake is found to be highly sensitive to the variations of f+ and Cµ. By increasing Cµ. and/or f+ the extent of the separated flow region behind the cylinder is observed to decrease. Indeed, at low f+ and/or high Cµ, periodic momentary interruptions of the vortex shedding are observed, while, for higher values of f+ and/or lower values of Cμ, a strong interaction between von Kármán vortices and synthetic jet vortex pairs occurs
SYNTHETIC JET-BASED CONTROL OF A CYLINDER WAKE / Greco, CARLO SALVATORE; Gaetano, Pascarella; Paolillo, Gerardo; Astarita, Tommaso; Cardone, Gennaro. - (2017). (Intervento presentato al convegno Italian Association of Aeronautics and Astronautics XXIV International Conference tenutosi a Palermo – Enna, Italy nel 18-22 September, 2017).
SYNTHETIC JET-BASED CONTROL OF A CYLINDER WAKE
GRECO, CARLO SALVATORE;PAOLILLO, GERARDO;ASTARITA, TOMMASO;CARDONE, GENNARO
2017
Abstract
Synthetic jets are zero-net mass flux flows that have been recently used in a wide range of flow control applications, among which the control of bluff body wakes. An optimal control is based on an appropriate tuning of the involved parameters, which implies knowledge of the effects of such parameters on the flow field. The present work reports on an experimental investigation of the active open-loop control of a cylinder wake at Reynolds number equal to 4980 using a slot synthetic jet located at the rear stagnation point. Three values of f+ (0.48, 0.96 and 1.92) are considered and, for each of them, Cµ is varied among as many different values (4.6%, 9.3% and 18.5%). The flow field in the cylinder wake is found to be highly sensitive to the variations of f+ and Cµ. By increasing Cµ. and/or f+ the extent of the separated flow region behind the cylinder is observed to decrease. Indeed, at low f+ and/or high Cµ, periodic momentary interruptions of the vortex shedding are observed, while, for higher values of f+ and/or lower values of Cμ, a strong interaction between von Kármán vortices and synthetic jet vortex pairs occursI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
