Synthetic Jet Actuator And Its Application In Active Flow Control

Active flow control is one of the leading areas of research in aviation and fluid dynamics, the unique characteristics of the synthetic jet flow-field and the working attributes of the actuators make synthetic jet actuators suitable for a large class of applications, now it is becoming one of the most promising international research fields. By experimental measurements, the formation and operation principle of the synthetic jet actuators, as well as the feasibility to apply synthetic jet to vectoring control are shown in the thesis.Experimental investigation on unsteady flow field structure near the rounded orifice of synthetic jet actuator is held with PIV measurement technique. Through the experimental results of both instantaneous and average flow fields show the formation and unsteady flow field characteristics of synthetic jet. more attention was paid to compare the characteristics of different flow fields when the parameters, such as: orifice diameter, orifice depth, relative amplitude of forcing voltage and orifice shape, were changed, which will be helpful to the design and optimization of the synthetic jet actuator.After a new kind of beveled orifice of synthetic jet actuator is designed, The PIV system supplemented by phase-locked technique is used in the experiment. the study of differences on flow characteristics between the parallel synthetic jet arrays with beveled and conventional straight orifices of synthetic jet actuator. The investigation results show that there is an obvious difference on flow structure between beveled and conventional straight orifice of synthetic jet actuator, to the right beveled orifice, a vortex is formed at the left sharp edge of orifice and wall-attachment effect is formed at the right edge of orifice. During the sucking period, the fluid is sucked into the actuator along the left edge of orifice. The energy and mass flux are transmitted horizontally. These characteristics show the great potential to be applied for boundary layer/shear layer separation flow control.Finally, the application of synthetic jet actuator with beveled orifice under the vectoring control of a primary jet is investigated. It is shown that the synthetic jet actuators can control the vector of a low speed primary jet effectively and the primary jet direction, the maximum of vectoring angle of the primary jet is up to 24 degree. The compares of the vectoring angle of the primary jet, through the parameters of forcing frequency, relative amplitude of forcing voltage, synthetic jet actuator angles, stimulation heights and the velocity of primary jet were changed, the results show that the synthetic jet actuator can effectively control low speed primary jet vectoring angle of the proportional control. The investigation results show while the velocity of primary jet is 10m/s and the momentum ratio between synthetic jet and primary jet is 1:43, vectoring angle of the primary jet is up to 13 degree, thus the energy of synthetic jet actuator is only 1.5W, with only very small energy input obtaining more performance benefits.