Experimental study of synthetic jets in a crossflow

• Main Author: Loh, Jenn Yen
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Aeronautical engineering
• Online Access: http://hdl.handle.net/10356/61003
• Institution: Nanyang Technological University

Synthetic jet actuator (SJA) is a flow separation control device which has been proved its capability to delay flow separation and improve aerodynamic performance. In this project, a study of behaviours of an array of two synthetic jets has been carried out in a turbulent flow over a zero-pressure-gradient flat plate. Both dye visualisation and PIV measurement were used to observe and obtain information about the flow under the influence of synthetic jets in different operating condition. Freestream velocity was fixed at 0.11m/s throughout the experiment. Synthetic jet actuator was first operated at =1.7, =144 and =0.15 and the effects of phase difference between two synthetic jets on the interaction in the turbulent boundary layer was observed. Comparison was also made between the synthetic jets array in turbulent cross flow and quiescent condition. In addition, by manipulating the oscillation frequency and diaphragm peak-to-peak displacement, the phase-averaged and time-averaged synthetic jet array were evaluated and compared. Analysis of PIV data was conducted to reveal the flow field of the synthetic jets. The contours of vorticity of synthetic jets at four phase differences were presented. Result from PIV data has a good agreement with dye visualisation observation. Time-averaged velocity profile of all cases were produced and evaluated. The result suggests that the merging of two synthetic jets is able to suppress the flow separation more effectively.