Arka Durma Noktasına Yerleştirilmiş Bir Sentetik Jet Eyleyici Kullanılarak Dairesel Bir Silindir Etrafındaki Akışın Sayısal Olarak İncelenmesi

Öz

Dairesel bir silindirin etrafındaki akışın kontrolü, aerodinamik sürükleme ve uyandırma dinamikleri üzerinde doğrudan etkiye sahiptir. Bu çalışmada, 200000 Reynolds sayısında dairesel bir silindir etrafındaki akış, arka durma noktasına yerleştirilmiş bir sentetik jet eyleyicisi kullanılarak incelenmiştir. Öncelikle temel akış deneysel veriyle doğrulanmış ve baskın girdap kopma frekansı spektral analiz ile belirlenmiştir. Daha sonra aktüatör, kilitlenme ve alt harmonik zorlamayı incelemek amacıyla doğal frekans ve bunun yarısı olan frekanslarda çalıştırılmıştır. Momentum katsayısı 0.004 - 0.0288 aralığında değiştirilerek parametrik bir analiz gerçekleştirilmiştir. Sonuçlar, alt harmonik zorlamanın daha yüksek performans sağladığını ve momentum katsayısı 0.0288 için yaklaşık %19.4 maksimum sürükleme azalması elde edildiğini göstermektedir. Aynı koşullarda harmonik zorlamada maksimum azalma yaklaşık %12 olarak bulunmuştur. Bulgular, frekans ve momentum girdisinin birlikte optimize edilmesinin önemini ortaya koymaktadır.

Anahtar Kelimeler

• Dairesel silindir
• HAD
• Sentetik jet eyleciyi
• Sürükleme katsayısı

Numerical Investigation of Flow Control of a Circular Cylinder Using a Synthetic Jet Actuator at the Rear Stagnation Point

Öz

Flow control of bluff bodies is of significant interest due to its direct impact on aerodynamic drag and wake dynamics. In this study, active flow control of a circular cylinder at a Reynolds number of 200000 is investigated using a synthetic jet actuator (SJA) positioned at the rear stagnation point. The baseline flow is first validated, and the dominant vortex shedding frequency is identified through spectral analysis. The actuator is then operated at the natural shedding frequency and its sub-harmonic to examine lock-on and sub-harmonic forcing effects. A parametric study is conducted by varying the momentum coefficient over the range of momentum coefficients between 0.0040 to 0.0288. The results show that sub-harmonic forcing provides superior performance, achieving a maximum drag reduction of approximately 19.4% at a momentum coefficient of 0.0288, while harmonic forcing results in a maximum reduction of about 12%. The findings demonstrate that both forcing frequency and momentum input play a critical role in wake manipulation, with sub-harmonic forcing offering a more effective strategy at high Reynolds numbers.

Anahtar Kelimeler

• Circular cylinder
• CFD
• Synthetic jet actuator
• Drag coefficient

Kaynakça

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