An experimental study of synthetic jets in a crossflow

• Main Author: Foo, Tun Gene.
• Other Authors: Tang Hui
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Mechanical engineering::Fluid mechanics
• Online Access: http://hdl.handle.net/10356/53250
• Institution: Nanyang Technological University

Synthetic jets are a type of jet flow which is made up of the surrounding fluid. They are generally produced by fluid motion generated through an orifice. They are popular for their zero-net-mass nature which eliminated the need for plumbing when applied to a base flow. Synthetic jets have been studied extensively for their ability to delay flow separation and hence reduce drag. The aim of the project was to study the interaction of multiple synthetic jets in quiescent and cross flow conditions. By modifying the orifice design, the student was able to create multiple synthetic jets. The detailed experimental setup and details of the design are discussed comprehensively in this report. The student utilized an analytical model of the synthetic jets consisting of various dimensionless parameters to facilitate the study of multiple synthetic jets. By varying the operating parameters of the experiment such as oscillating frequency and amplitude, the student was able to observe and study the different vortex structures and interactions of the multiple synthetic jets. It was observed that the Reynolds numbers plays a vital role in multiple synthetic jets interaction. At high Reynolds numbers, the synthetic jets interact violently with each other resulting in a non-defined structure. At low Reynolds Numbers, although the formation of the synthetic jets is well defined, the multiple jets have insufficient momentum to propagate through the boundary layer. At middle range Reynolds numbers, it was observed that the multiple synthetic jets were able to combine into a single flow structure which had greater momentum and propulsion, resulting in better interaction with the boundary layer. The findings of the project have been summarized in the report. Several improvements have also been suggested for future study on the topic of multiple synthetic jets interaction.