The sound generated by a square cylinder with a splitter plate at low Reynolds number

2011 ◽  
Vol 330 (15) ◽  
pp. 3620-3635 ◽  
Author(s):  
Mohamed Sukri Mat Ali ◽  
Con J. Doolan ◽  
Vincent Wheatley
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Splitter Plate ◽  
Square Cylinder ◽  
Low Reynolds

Low Reynolds number flow over a square cylinder with a splitter plate

2011 ◽  
Vol 23 (3) ◽  
pp. 033602 ◽  
Author(s):  
Mohamed Sukri Mat Ali ◽  
Con J. Doolan ◽  
Vincent Wheatley
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Splitter Plate ◽  
Square Cylinder ◽  
Low Reynolds Number Flow ◽  
Reynolds Number Flow ◽  
Number Flow ◽  
Low Reynolds

Model reduction and mechanism for the vortex-induced vibrations of bluff bodies

2017 ◽  
Vol 827 ◽  
pp. 357-393 ◽  
Author(s):  
W. Yao ◽  
R. K. Jaiman
Keyword(s):  
Reynolds Number ◽  
Bluff Body ◽  
Low Reynolds Number ◽  
Smooth Curve ◽  
Bluff Bodies ◽  
Sharp Corner ◽  
Mass Ratio ◽  
Square Cylinder ◽  
Low Reynolds ◽  
Lock In

We present an effective reduced-order model (ROM) technique to couple an incompressible flow with a transversely vibrating bluff body in a state-space format. The ROM of the unsteady wake flow is based on the Navier–Stokes equations and is constructed by means of an eigensystem realization algorithm (ERA). We investigate the underlying mechanism of vortex-induced vibration (VIV) of a circular cylinder at low Reynolds number via linear stability analysis. To understand the frequency lock-in mechanism and self-sustained VIV phenomenon, a systematic analysis is performed by examining the eigenvalue trajectories of the ERA-based ROM for a range of reduced oscillation frequency $(F_{s})$, while maintaining fixed values of the Reynolds number ($Re$) and mass ratio ($m^{\ast }$). The effects of the Reynolds number $Re$, the mass ratio $m^{\ast }$ and the rounding of a square cylinder are examined to generalize the proposed ERA-based ROM for the VIV lock-in analysis. The considered cylinder configurations are a basic square with sharp corners, a circle and three intermediate rounded squares, which are created by varying a single rounding parameter. The results show that the two frequency lock-in regimes, the so-called resonance and flutter, only exist when certain conditions are satisfied, and the regimes have a strong dependence on the shape of the bluff body, the Reynolds number and the mass ratio. In addition, the frequency lock-in during VIV of a square cylinder is found to be dominated by the resonance regime, without any coupled-mode flutter at low Reynolds number. To further discern the influence of geometry on the VIV lock-in mechanism, we consider the smooth curve geometry of an ellipse and two sharp corner geometries of forward triangle and diamond-shaped bluff bodies. While the ellipse and diamond geometries exhibit the flutter and mixed resonance–flutter regimes, the forward triangle undergoes only the flutter-induced lock-in for $30\leqslant Re\leqslant 100$ at $m^{\ast }=10$. In the case of the forward triangle configuration, the ERA-based ROM accurately predicts the low-frequency galloping instability. We observe a kink in the amplitude response associated with 1:3 synchronization, whereby the forward triangular body oscillates at a single dominant frequency but the lift force has a frequency component at three times the body oscillation frequency. Finally, we present a stability phase diagram to summarize the VIV lock-in regimes of the five smooth-curve- and sharp-corner-based bluff bodies. These findings attempt to generalize our understanding of the VIV lock-in mechanism for bluff bodies at low Reynolds number. The proposed ERA-based ROM is found to be accurate, efficient and easy to use for the linear stability analysis of VIV, and it can have a profound impact on the development of control strategies for nonlinear vortex shedding and VIV.

Suppression of fluid force on flow past a square cylinder with a detached flat plate at low Reynolds number for various spacing ratios

2014 ◽  
Vol 28 (12) ◽  
pp. 4969-4978 ◽  
Author(s):  
Shams Ul Islam ◽  
Hamid Rahman ◽  
Waqas Sarwar Abbasi ◽  
Uzma Noreen ◽  
Aftab Khan
Keyword(s):  
Reynolds Number ◽  
Flat Plate ◽  
Low Reynolds Number ◽  
Square Cylinder ◽  
Fluid Force ◽  
Flow Past ◽  
Low Reynolds

Linear shear flow over a square cylinder at low Reynolds number

2005 ◽  
Vol 17 (7) ◽  
pp. 078103 ◽  
Author(s):  
M. Cheng ◽  
S. H. N. Tan ◽  
K. C. Hung
Keyword(s):  
Reynolds Number ◽  
Shear Flow ◽  
Low Reynolds Number ◽  
Square Cylinder ◽  
Linear Shear ◽  
Low Reynolds

Low‐Reynolds number flow over a rotatable cylinder–splitter plate body

1990 ◽  
Vol 2 (11) ◽  
pp. 1925-1927 ◽  
Author(s):  
John C. Xu ◽  
Mihir Sen ◽  
Mohamed Gad‐el‐Hak
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Splitter Plate ◽  
Low Reynolds Number Flow ◽  
Reynolds Number Flow ◽  
Number Flow ◽  
Low Reynolds
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