Effect of the Oscillator Length on the Characteristics of a Feedback Type Fluidic Oscillator

Bu çalışma sabit derinlikli ve aynı ana geometrik boyutlara sahip çeşitli uzunluktaki fluidik osilatörleri karakterize etmektedir. Fluidik osilatörün uzunluğundaki bir değişim osilatörün osilasyon frekansı ve süpürme karakteristiklerini etkilemektedir. Bu karakteristikler Sabit Sıcaklık Anemometri Sistemi sıcak-tel ölçümleri ile ve su akış vizülasyonları ile ortaya çıkarılmıştır. Toplamda on adet değişik uzunluktaki fluidik osilatör, refereans modeli ile karşılaştırılmıştır. Fluidik osilatörün kısaltılmasının belli bir eşik uzunluğundan sonra osilasyonları durdurduğu, uzatılmasının ise aşamalı olarak osilasyon frekansı ve süpürme açısını azalttığı gözlemlenmiştir. Ayrıca, sıcak-tel ölçümlerinden her osilatör için elde edilen frekans haritaları sayesinde osilasyon frekanslarının kapsamlı detayları da geniş bir debi aralığı için verilmiştir. Osilatörün osilasyon frekansının ve süpürme açısının sabit olacağı sabit bir besleme debisi için fluidik osilatör uzunluğunun değiştirilmesi, bu iki karakterin değiştirilmesine olanak verecektir.Böylece osilatör kullanılacağı uygulamanın özel ihtiyaçlarına göre adapte edilebilecektir.

Anahtar Kelimeler:

Experimental Fluid Mechanics, Aerodynamic Flow Control, Flow Control Actuators, Fluidic Oscillators

Effect of the Oscillator Length on the Characteristics of a Feedback Type Fluidic Oscillator

This work characterizes the various length fluidic oscillators with constant depth and having the same main geometric dimensions. A change in fluidic oscillator's length affects the frequency and sweeping characteristics of the fluidic oscillators. These characteristics were extracted by means of constant temperature anemometry hot-wire measurements and water flow visualizations. A total number of ten fluidic oscillators were compared to the baseline fluidic oscillator design. It was observed that shortening the fluidic oscillator ceases the oscillations after a threshold oscillator length whereas elongating the fluidic oscillator decreases the frequency and sweep angle gradually. Furthermore, the frequency maps obtained from hot-wire measurements for each considered fluidic oscillator design provided overall detail about the frequency of the oscillations for a wide range of flow rate. For a constant supply flow rate where the frequency and the sweep angle of an oscillator is constant, changing the length of a fluidic oscillator will allow varying these characteristics of the oscillator. Thus the oscillator can be tailored for a specific need of an application.

Keywords:

Experimental Fluid Mechanics, Aerodynamic Flow Control, Flow Control Actuators, Fluidic Oscillators,

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