Date of Award


Publication Type

Master Thesis

Degree Name



Mechanical, Automotive, and Materials Engineering


Applied sciences


Gary Rankin




The performance of a synthetic jet ejector (SJE) has been investigated numerically using Computational Fluid Dynamics (CFD). A parametric study was conducted and combined with a search procedure to determine the conditions for optimum volume flow rate through the device. Active parameters such as input driving frequency and input velocity amplitude as well as passive parameters describing the ejector geometry, such as the orifice diameter, shroud diameter, and shroud length were considered.

Results show that the SJE has an optimum operating condition. The optimum orifice diameter is theoretically the same as the actuator diameter, which is 0.8 times the shroud diameter. The optimum shroud length is 4 times the shroud diameter. The corresponding Strouhal number and Reynolds number are 0.323 and 20,000, respectively.

The use of this particular SJE configuration to replace the ventilation fan in an automotive seat cooling application is also considered. The SJE for this application has an orifice diameter of 16 mm, a shroud diameter of 20 mm, and a shroud length of 80 mm, with a driving frequency of 250 Hz, and input velocity amplitude of 15.5 m/s. It is shown that 10 such devices operating in parallel would be required to attain the same ventilation as existing fans.