The supersonic impinging jet flowfield has many applications in engineering including Short Take-Off and Vertical Landing (STOVL) aircraft, which will be the primary application considered in this paper. Supersonic impinging jets characteristic of STOVL aircraft have undesirable features which result in dangerously high noise levels, sonic fatigue of the aircraft underbody, lift loss due to flow entrainment, exhaust and debris ingestion, and severe ground erosion. One method for controlling this flowfield is the injection of high momentum microjets at the nozzle exit plane. As an extension of this control method, a microfluidic actuator using resonance phenomena to produce high frequency pulsed microjets has been developed. In this study, these Resonance-Enhanced Microjet (REM) actuators were implemented into the STOVL flowfield in order to pulse the microjet injection at timescales on the same order as the dominant resonant frequency of the primary jet flowfield. The goal of this study is to compare the effects of steady microjet control and pulsed microjet control on the impinging jet flowfield. These control schemes are both capable of reducing or eliminating jet impingement tones as well as reducing the ground plane and nearfield acoustic overall noise levels by as much as 8 dB. These control methods have also both shown substantial reduction in overall jet unsteadiness and the elimination of the large scale vortical structures present in the uncontrolled impinging jet's shear layer. Additionally, unsteady pressure measurements taken within the actuators as well as Particle Image Velocimetry (PIV) results yield some insight into the operational regimes of REM actuators as well as their resulting effects on the supersonic impinging jet flowfield. / A Thesis submitted to the Department of Mechanical Engineering in partial fulfillment of the requirements for the degree of Master of Science. / Summer Semester, 2012. / June 29, 2012. / Actuators, Impinging Jets, Noise Control / Includes bibliographical references. / Farrukh Alvi, Professor Directing Thesis; Kunihiko Taira, Committee Member; Carl Moore, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_183132 |
| Contributors | Strickland, Garrett M. (authoraut), Alvi, Farrukh (professor directing thesis), Taira, Kunihiko (committee member), Moore, Carl (committee member), Department of Mechanical Engineering (degree granting department), Florida State University (degree granting institution) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource, computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
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