Aperiodic phenomena in planar oscillatory flow past a square arrangement of four cylinders at low pitch ratios

2012 ◽  
Vol 52 ◽  
pp. 91-104 ◽  
Author(s):  
P. Anagnostopoulos ◽  
Ch. Dikarou
Keyword(s):  
Oscillatory Flow ◽  
Flow Past ◽  
Four Cylinders

Oscillatory flow past a circular cylinder in a rotating frame

1997 ◽  
Vol 345 ◽  
pp. 101-131
Author(s):  
M. D. KUNKA ◽  
M. R. FOSTER
Keyword(s):  
Circular Cylinder ◽  
Steady Flow ◽  
Stagnation Point ◽  
Oscillatory Flow ◽  
Numerical Solutions ◽  
Initial Conditions ◽  
Temporal Integration ◽  
Oncoming Flow ◽  
Flow Past ◽  
Rear Stagnation Point

Because of the importance of oscillatory components in the oncoming flow at certain oceanic topographic features, we investigate the oscillatory flow past a circular cylinder in an homogeneous rotating fluid. When the oncoming flow is non-reversing, and for relatively low-frequency oscillations, the modifications to the equivalent steady flow arise principally in the ‘quarter layer’ on the surface of the cylinder. An incipient-separation criterion is found as a limitation on the magnitude of the Rossby number, as in the steady-flow case. We present exact solutions for a number of asymptotic cases, at both large frequency and small nonlinearity. We also report numerical solutions of the nonlinear quarter-layer equation for a range of parameters, obtained by a temporal integration. Near the rear stagnation point of the cylinder, we find a generalized velocity ‘plateau’ similar to that of the steady-flow problem, in which all harmonics of the free-stream oscillation may be present. Further, we determine that, for certain initial conditions, the boundary-layer flow develops a finite-time singularity in the neighbourhood of the rear stagnation point.

Oscillatory flow regimes around four cylinders in a diamond arrangement

2019 ◽  
Vol 877 ◽  
pp. 955-1006 ◽  
Author(s):  
Chengjiao Ren ◽  
Liang Cheng ◽  
Feifei Tong ◽  
Chengwang Xiong ◽  
Tingguo Chen
Keyword(s):  
Oscillatory Flow ◽  
Bluff Body ◽  
Substantial Reduction ◽  
Period Doubling ◽  
Flow Regimes ◽  
Mode Competition ◽  
Single Type ◽  
Phase Dynamics ◽  
Flow Features ◽  
Four Cylinders

Oscillatory flow around a cluster of four circular cylinders in a diamond arrangement is investigated using two-dimensional direct numerical simulation over Keulegan–Carpenter numbers (KC) ranging from 4 to 12 and Reynolds numbers (Re) from 40 to 230 at four gap-to-diameter ratios (G) of 0.5, 1, 2 and 4. Three types of flows, namely synchronous, quasi-periodic and desynchronized flows (along with 14 flow regimes) are mapped out in the (G, KC, Re)-parameter space. The observed flow characteristics around four cylinders in a diamond arrangement show a few unique features that are absent in the flow around four cylinders in a square arrangement reported by Tong et al. (J. Fluid Mech., vol. 769, 2015, pp. 298–336). These include (i) the dominance of flow around the cluster-scale structure at $G=0.5$ and 1, (ii) a substantial reduction of regime D flows in the regime maps, (iii) new quasi-periodic (phase trapping) $\text{D}^{\prime }$ (at $G=0.5$ and 1) and period-doubling $\text{A}^{\prime }$ flows (at $G=1$) and most noteworthily (iv) abnormal behaviours at ($G\leqslant 2$) (referred to as holes hereafter) such as the appearance of spatio-temporal synchronized flows in an area surrounded by a single type of synchronized flow in the regime map ($G=0.5$). The mode competition between the cluster-scale and cylinder-scale flows is identified as the key flow mechanism responsible for those unique flow features, with the support of evidence derived from quantitative analysis. Phase dynamics is introduced for the first time in bluff-body flows, to the best knowledge of the authors, to quantitatively interpret the flow response (e.g. quasi-periodic flow features) around the cluster. It is instrumental in revealing the nature of regime $\text{D}^{\prime }$ flows where the cluster-scale flow features are largely synchronized with the forcing of incoming oscillatory flow (phase trapping) but are modulated by localized flow features.

Errata: MHD Oscillatory Flow Past a Semi-Infinite Plate

AIAA Journal ◽  
1978 ◽  
Vol 16 (1) ◽  
pp. 0096b-0096b
Author(s):  
V. M. Soundalgekar ◽  
H. S. Takhar
Keyword(s):  
Oscillatory Flow ◽  
Infinite Plate ◽  
Flow Past

Blockage effect of oscillatory flow past a fixed cylinder

2004 ◽  
Vol 26 (3-4) ◽  
pp. 147-153 ◽  
Author(s):  
P. Anagnostopoulos ◽  
R. Minear
Keyword(s):  
Oscillatory Flow ◽  
Flow Past ◽  
Fixed Cylinder ◽  
Blockage Effect

The initial oscillatory flow past a circular cylinder

1995 ◽  
Vol 29 (3) ◽  
pp. 255-269 ◽  
Author(s):  
H. M. Badr ◽  
S. C. R. Dennis ◽  
S. Kocabiyik
Keyword(s):  
Circular Cylinder ◽  
Oscillatory Flow ◽  
Flow Past

Variable Order Modeling of Diffusive-convective Effects on the Oscillatory Flow Past a Sphere

2008 ◽  
Vol 14 (9-10) ◽  
pp. 1659-1672 ◽  
Author(s):  
H.T.C. Pedro ◽  
M.H. Kobayashi ◽  
J.M.C. Pereira ◽  
C.F.M. Coimbra
Keyword(s):  
Oscillatory Flow ◽  
Variable Order ◽  
Flow Past ◽  
Flow Past A Sphere
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