Active control of flow separation over an airfoil using synthetic jets

Abstract

We perform large-eddy simulation of turbulent flow separation over an airfoil and evaluate the effectiveness of synthetic jets as a separation control technique. The flow configuration consists of flow over an NACA 0015 airfoil at Reynolds number of 896,000 based on the airfoil chord length and freestream velocity. A small slot across the entire span connected to a cavity inside the airfoil is employed to produce oscillatory synthetic jets. Detailed flow structures inside the synthetic-jet actuator and the synthetic-jet/cross-flow interaction are simulated using an unstructured-grid finite-volume large-eddy simulation solver. Simulation results are compared with the 2005 experimental data of Gilarranz et al., and qualitative and quantitative agreements are obtained for both uncontrolled and controlled cases. As in the experiment, the present large-eddy simulation confirms that synthetic-jet actuation effectively delays the onset of flow separation and causes a significant increase in the lift coefficient. Modification of the blade boundary layer due to oscillatory blowing and suction and its role in separation control is discussed. r

Numerical investigation of the influence of nozzle geometrical parameters on thrust of synthetic jet underwater

“…You, Moin [32] studied and evaluated the effectiveness of synthetic jets as a separation control technique over an airfoil. Wu, Leschziner [33] investigated the physical processes involved in the injection of a synthetic jet in quiescent surroundings using LES.…”

Comparison of synthetic jet actuators based on sharp-edged and round-edged nozzles

“…Generally, the interval represents time periods where the surface integrals from Eqs. (3,4,5) are greater or equal to zero. Figure 1 shows the schematic view of the tested SJAs that were operated at standard room conditions (temperature 20 − 25 • C and barometric pressure 97 − 99 kPa) with air as the working fluid.…”

“…The velocity profiles measured at the distance x = 0.3 mm were acquired at 14 discrete positions along the nozzle diameter and the data were used for evaluation of U 0 and the integral quantities defined by Eqs. (3,4,5).…”

“…The potential applications have been found especially in boundary-layer separation control [3][4][5][6][7][8][9][10], jet vectoring [11][12][13][14][15][16], heat transfer enhancement [17][18][19][20][21][22], and mixing [23][24][25]. A variant of the SJ, namely a non-zero-net-mass-flux jet (or hybrid SJ), has been investigated more recently [26-28, 21, 29-31].…”

A new method for fluid input into a hybrid synthetic jet actuator

“…Hybrid synthetic jets (HSJs, or non-zeronet-mass-flux jets), which were first introduced in [4][5][6], are very similar to SJs; they are generated by means of non-zero-net-mass flow in the nozzle. The applications of both, SJs and HSJs, may be found especially in boundarylayer separation control [7][8][9], jet vectoring [10], and heat transfer enhancement [11,12,6,13,14].…”