Dairesel Silindir Çevresindeki Pasif Akış Kontrolünün Sayısal İncelenmesi

Mevcut çalışmada, delikli bir silindirin, duvara monte edilmiş dairesel bir silindir etrafındaki pasif akış kontrolü üzerindeki etkileri incelenmiştir. Delikli silindir, tek dairesel silindirin dışına eş merkezli olarak yerleştirilmiştir. Akış alanının çözümlenmesinde büyük girdap simülasyonu kullanıldı. Çalışma hem tekil silindir üzerine etkiyen sürükleme kuvveti katsayısının azaltılmasını hem de aşağı akış bölgesinde girdap kopmalarından kaynaklanan ve silindir üzerine etkiyen değişken kuvvetlerin kontrol edilmesini amaçlamıştır. Sonuçlar, tekil silindirin aşağı akış girdap bölgesindeki akış yapılarının delikli silindirin eş merkezli olarak yerleştirilmesinden sonra önemli ölçüde değiştiğini ortaya koymuştur. Örnek olarak, von Karman girdap yapıları artık oluşmamıştır, ve aşağı akış girdap bölgesinde türbülans kinetik enerji miktarı önemli ölçüde azalmıştır. Tek silindirin zaman ortalamalı sürtünme katsayısı değeri %69 oranında azalmıştır. Ayrıca, tek silindirin zamana bağlı kaldırma kuvveti katsayısının maksimum büyüklüğü, delikli silindir tek silindirin dışına eşmerkezli olarak yerleştirildikten sonra sekiz kat azalmıştır.

Anahtar Kelimeler:

Silindir, Sürtünme direnci, Akış kontrolü, BGS, Girdap kopması

Numerical Investigation of the Passive Flow Control Around a Circular Cylinder

The effects of a perforated cylinder on the passive flow control around a circular cylinder mounted on a wall were investigated. The perforated cylinder was placed outside of the single circular cylinder concentrically. The large-eddy simulation was used to resolve the flow field. The study was aimed at both reducing the drag coefficient of the single cylinder and controlling the fluctuating forces acting on the single cylinder caused by vortex shedding in the downstream wake. The results showed that the structure of the downstream wake flow of the single cylinder changed significantly after placing the perforated cylinder. For example, von Karman vortices disappeared, and the maximum magnitude of turbulent kinetic energy, TKE, in the downstream wake was reduced. The time-averaged drag coefficient of the single cylinder was decreased by 69%. In addition, the maximum value of the lift coefficient of the single cylinder was reduced by eight times when the perforated cylinder was placed outside the single cylinder.

Keywords:

Cylinder, Drag, Flow control, LES, Vortex shedding,

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