Please use this identifier to cite or link to this item: https://hdl.handle.net/20.500.11851/6603
Title: EFFECTS OF AIR BLOWING ON TURBULENT FLOW OVER A CIRCULAR CYLINDER
Authors: Apaçoğlu, Buryan
Paksoy, Akın
Aradağ, Selin
Keywords: Circular cylinder
Von Karman vortex street
Flow control
Blowing
Proper Orthogonal Decomposition
Issue Date: 2012
Publisher: Turkish Soc Thermal Sciences Technology
Abstract: This study analyzes the flow over a two-dimensional (2D) circular cylinder at a turbulent Reynolds number of 20,000 and its control by air blowing from several slots located on the surface of the cylinder, computationally. CFD simulations are performed by using Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations and Spalart-Allmaras turbulence model. Uncontrolled flow simulation results are validated using the experimental results available in literature for drag coefficient, Strouhal number, time-averaged pressure coefficient distribution on the circumference of the cylinder and mean velocity values at the downstream. Air blowing from several slots located on the cylinder is used as an actuator for forcing the flow. Blowing from four slots located on the circumference of the cylinder with a velocity magnitude of 50% of the free stream velocity yields a drag reduction of 23% compared to the uncontrolled case. Additionally, near wake region is further examined by application of Proper Orthogonal Decomposition (POD) technique. A Fast Fourier Transform (FFT) based spatial filtering procedure is employed in order to separate the effects of small-scale turbulent structures in the wake region. The FFT-filtered snapshot-based POD analysis shows that approximately 99% of the total energy of the flow can be represented by considering only the most energetic first two modes where the effects of von Karman vortex street can be seen appropriately both for uncontrolled and controlled flow cases.
URI: https://search.trdizin.gov.tr/yayin/detay/136623
https://hdl.handle.net/20.500.11851/6603
ISSN: 1300-3615
Appears in Collections:Makine Mühendisliği Bölümü / Department of Mechanical Engineering
Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
TR Dizin İndeksli Yayınlar / TR Dizin Indexed Publications Collection
WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

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