Sığ suda yan yana silindirler arasına akışa dik yerleştirilen plakaların akış özelliklerine etkisi

Öz

Bu çalışmada yan yana iki silindir arasına akış doğrultusuna dik yönde yerleştirilen plakaların silindirler arkasındaki akış bölgesine etkisi deneysel olarak Parçacık Görüntülü Hız Ölçümü (PIV) yöntemi ile incelenmiştir. Akrilik malzemeden üretilen dairesel silindirlerin çapı D=40 mm’dir. Deneyler süresince hw=20 mm derinliğindeki sığ su akışında akış görüntüleri hl=10 mm yükseklikten alınmıştır. Suyun akış hızı U_∞ =125 mm/sn ve silindirlerin çapına bağlı Reynolds sayısı ReD=5000’dir. Yükseklikleri 2 mm artımla H=2 mm ile 10mm arasında değişen beş farklı plaka daimi olmayan akışı kontrol etmek için kullanılmıştır. Bütün durumlarda açıklık oranı G/D=1.25  olarak sabit tutulmuştur. Deneysel olarak elde edilen verilerin bilgisayarda işlenmesiyle, boyutsuz Türbülans Kinetik Enerji değerleri ve ortalama hız vektörleri elde edilmiştir. Sonuç olarak, plaka kullanımı akış kontrolündeki etkinliğini net bir şekilde ortaya koymaktadır.  H=6 mm plaka yüksekliğinden sonra TKE değerlerinde dikkate değer bir azalma gözlenmektedir. Akış kontrolünün sağlandığı en etkili plaka yüksekliği ise H=10  mm olarak görülmektedir.

Anahtar Kelimeler

• Dik plaka,Girdap,Pasif kontrol,PIV,Sığ su

The effect of the splitter plates on flow characteristics that are vertically placed to the flow between side by side cylinders in shallow water

Abstract

In this paper, flow changes were observed via Particulate Image Velocimetry (PIV) technique in shallow water flow for two side by side circular cylinders which a vertically placed splitter plate (VSP) was placed between them. The circular cylinders made of acrylic material have a diameter of D=40 mm. Throughout the experiments water height was  hw=20 mm and flow images were taken at the elevation of hl=10 mm. The free stream velocity was U_∞ = 125mm/sec and Reynolds Number was ReD=5000  based on diameters of circular cylinders.  Five different VSPs varied from heights of H=2 mm to 10 mm with an increment 2 mm were used to control unsteady flow. The gap/diameter ratio was G/D=1.25 for all cases. Dimensionless Turbulence Kinetic Energy values and time-averaged velocity vectors ​​were acquired by processing experimentally obtained data on a computer. As a result, the usage of splitter plate has shown its effectiveness on flow control. After the plate height of H=6 mm, TKE values were decreased significantly. The most effective plate height on the flow control was seen as H=10  mm.

Keywords

• Vertical splitter plate,Vortex,Passive control,PIV,Shallow water

Kaynakça

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