Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Conference Object Citation - Scopus: 11Jet Interactions in a Feedback- Free Fluidic Oscillator at Low Flow Rate(American Institute of Aeronautics and Astronautics Inc. custserv@aiaa.org, 2013-06-22) Tomac, Mehmet N.; Gregory, James W.In this work, the internal fluid dynamics and frequency characteristics of feedback-free fluidic oscillators are investigated experimentally for low flow rates below 3.4 mL/s. The internal flow field of feedback-free fluidic oscillator was extracted using a refractive index-matched Particle Image Velocimetry (PIV) technique with the help of a problem-specific sensor setup for simultaneous frequency measurements in refractive index matching fluid. The oscillation mechanism for the low flow rate region was revealed with PIV measurements. Flow topologies extracted with the measurements were found to exhibit various flow features and the details of the jets interactions and vortical balance that lead to oscillatory behavior were discussed. © 2020 Elsevier B.V., All rights reserved.Article Citation - WoS: 12Citation - Scopus: 14Internal Flow Physics of a Fluidic Oscillator Spray in the Transition Regime(Begell House inc, 2016) Tomac, Mehmet N.; Gregory, James W.An experimental investigation of the underlying flow physics of a dual-jet interaction fluidic oscillator spray has been conducted in the transition regime for a Reynolds number of 1680. The transition regime is defined as a narrow range of flow rates between two other operating modes of the fluidic oscillator. Particle image velocimetry (PIV) was used with refractive index-matching sodium iodide solution to minimize reflections from the spray geometry and obtain detailed internal velocity fields. PIV results show that the interaction of the two internal jets and the resultant vortices are responsible for the oscillation mechanism in the transition regime. Two side vortices sustain their existence throughout the oscillation period by altering their size, shape, and strength, and a dome vortex is created twice each oscillation period (once from each jet). The dome vortex plays a key role in the kinetic energy transfer mechanism inside the oscillator by means of jet bifurcations. The primary oscillation mechanism in the transition regime is that each internal jet's connection with the exiting jet is cut completely by the dome vortex in every period. This is in contrast to the low-flow rate oscillation mechanism, in which the oscillations are created by continuous collisions of the jets. Furthermore, the internal jets are observed to energize the side vortex on the opposite side of the chamber-a phenomenon that was not observed in the low-flow rate regime.Conference Object Citation - Scopus: 154A Review of Fluidic Oscillator Development and Application for Flow Control(2013) Gregory, James W.; Tomac, Mehmet N.This review provides a detailed discussion of the historical development of fluidic oscillators and their application to flow control. Fluidic oscillators were initially developed in the 1960's for a variety of applications, and have seen resurgent interest for their suitability for modern flow control applications. The devices produce an oscillating jet of fluid over a wide fan angle and have no moving parts, making them an attractive actuator concept. This review aims to highlight the most important historical papers of relevance to modern fluidic oscillator development. The reviewed works will extend from the early 1960's to the most recent investigations, with a focus on the fundamental operating mechanisms of fluidic oscillators. The authors present this review as a short synopsis of fluidic oscillators for flow control, while a more comprehensive review will be submitted for archival publication in the near future. © 2013 Elsevier B.V., All rights reserved.