Identification of flow regimes around two staggered square cylinders by a numerical study

2017 ◽  
Vol 31 (3) ◽  
pp. 295-315 ◽  
Author(s):  
J. Aboueian ◽  
A. Sohankar
Keyword(s):  
Numerical Study ◽  
Flow Regimes ◽  
Square Cylinders

Simulation of flow across a row of transversely oscillating square cylinders

2011 ◽  
Vol 680 ◽  
pp. 361-397 ◽  
Author(s):  
C. M. SEWATKAR ◽  
ATUL SHARMA ◽  
AMIT AGRAWAL
Keyword(s):  
Reynolds Number ◽  
Oscillation Frequency ◽  
Amplitude Ratio ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Oscillation Amplitude ◽  
Flow Regimes ◽  
Flow Parameters ◽  
Square Cylinders ◽  
Wake Interaction

A numerical study of flow across a row of transversely oscillating square cylinders (of diameter d) has been undertaken using the lattice Boltzmann method, for a better understanding of fluid–structure interaction problems. The effects of cylinder oscillation frequency ratio (fe/fo, where fe is the cylinder oscillation frequency and fo is the corresponding vortex shedding frequency for stationary row of cylinders), amplitude ratio (A/d), non-dimensional spacing between the cylinders (s/d) and Reynolds number (Re) on ensuing flow regimes and flow parameters have been studied to understand the flow physics. Six different flow regimes observed in this study are the quasi-periodic non-lock-on-I, synchronous lock-on, quasi-periodic lock-on, quasi-periodic non-lock-on-II, synchronous non-lock-on and chaotic non-lock-on. It is observed that the range of the lock-on regime depends upon the relative dominance of incoming flow and cylinder motion. Although the lock-on regime in the case of Re = 80, s/d = 4 and A/d = 0.2 is substantially larger as compared to that for a single oscillating cylinder, the range of the lock-on regime shrinks with a reduction in the cylinder spacing, increase in the Reynolds number or decrease in the oscillation amplitude. It is also observed that the wake interaction behind the cylinders weakens with an increase in fe/fo, Re, A/d or s/d, leading to the formation of independent wakes and synchronous nature of the flow. For fe/fo ≥ 1.2, independent and intact oscillating wakes are noted and an additional frequency (wake oscillation frequency) is obtained in the time series of the lift coefficient. Although it was expected that the complexity in the wake interaction would increase with cylinder oscillation or amplitude ratio, an opposite effect (that is, formation of independent wakes) is noted from the results.

A Numerical Study for Flow Around Three Square Cylinders in Triangular Arrangement

2019 ◽  
Vol 44 (1) ◽  
pp. 229-246 ◽  
Author(s):  
H. Rahman ◽  
S. U. Islam ◽  
W. S. Abbasi ◽  
G. Nazeer
Keyword(s):  
Numerical Study ◽  
Square Cylinders

Flow Around a Conical Nose with Rounded Tail Projectile for Subsonic, Transonic, and Supersonic Flow Regimes : A Numerical Study

2014 ◽  
Vol 64 (6) ◽  
pp. 509-516
Author(s):  
Amitesh Kumar ◽  
◽  
H.S. Panda ◽  
T.K. Biswal ◽  
R. Appavuraj ◽  
...  
Keyword(s):  
Supersonic Flow ◽  
Numerical Study ◽  
Flow Regimes

scholarly journals Numerical Study of Mixing Flow Regimes Generated by Different Coaxial Jet Geometries

2015 ◽  
Vol 16 (AEROSPACE SCIENCES) ◽  
pp. 1-14
Author(s):  
M. Nour-Eldin ◽  
I. Elbadawy ◽  
M. Eltelbany
Keyword(s):  
Numerical Study ◽  
Flow Regimes

Fluid dynamics around three cylinders in presence of small control cylinders

2020 ◽  
Vol 98 (11) ◽  
pp. 1060-1076
Author(s):  
Ali Ahmed ◽  
Shams-ul Islam ◽  
Chao Ying Zhou ◽  
Raheela Manzoor
Keyword(s):  
Drag Coefficient ◽  
Flow Regime ◽  
Strouhal Number ◽  
Numerical Study ◽  
Critical Flow ◽  
Square Cylinders ◽  
Tandem Square Cylinders ◽  
Critical Flow Regime ◽  
Force Reduction ◽  
Control Cylinder

A numerical study is performed to analyze the effect of small control cylinders on fluid force reduction and vortex shedding suppression on the flow past three inline square cylinders using the lattice Boltzmann method. The Reynolds number Re = 160 is fixed while the spacing between the cylinders is taken in the range of 1.0D ≤ g* ≤ 5.0D (where D is the size of the main cylinder) and the control cylinder size is varied from 0.1D to 0.5D. To systematically understand the effect of control cylinders on the forces, a detailed analysis of Strouhal number (St), mean drag coefficient (CDmean), and root mean square values of the drag and lift coefficients is presented in this paper. In this study, it is observed that the average mean drag coefficient (CDmeanaverage) and Strouhal number reached either maximum or minimum values at different values of separation ratio (g*) and small control cylinder size (d). It is found that at (g*, d) = (5.0, 0.0) and (1.0, 0.5), the average CDmean attains its maximum (CDmeanaverage = 0.7813) and minimum (CDmean = 0.0988) values. Furthermore, at (g*, d) = (5.0, 0.3) and (2.0, 0.0) the average St attains its maximum (St = 0.1780) and minimum (St = 0.041) values. It is found that the flow regimes completely change in the presence of control cylinders. In particular, at g* = 4.0 there is a critical flow regime when the size of the control cylinder changes from 0.1 to 0.5. The sudden jump in the mean drag coefficient and Strouhal number for the middle cylinder with their maximum and minimum values also confirms the critical flow regime. The effect of control cylinders within tandem square cylinders has not been studied before.

Sign in / Sign up

Export Citation Format

Share Document