scholarly journals Phase-locking of laminar wake to periodic vibrations of a circular cylinder

2021 ◽  
Vol 6 (3) ◽  
Author(s):  
M. A. Khodkar ◽  
Joseph T. Klamo ◽  
Kunihiko Taira
Keyword(s):  
Circular Cylinder ◽  
Phase Locking ◽  
Laminar Wake

The effect of confining walls on the stability of the steady wake behind a circular cylinder

1963 ◽  
Vol 17 (4) ◽  
pp. 546-550 ◽  
Author(s):  
F. H. Shair* ◽  
A. S. Grove ◽  
E. E. Petersen ◽  
A. Acrivos
Keyword(s):  
Experimental Investigation ◽  
Circular Cylinder ◽  
Experimental Equipment ◽  
Laminar Wake ◽  
The Stability ◽  
Steady Laminar

The results of an experimental investigation are presented to show that the stability of the steady laminar wake behind a circular cylinder is strongly influenced by the proximity of the walls of the confining experimental equipment.

Computation of Vortex Lock-In in the Laminar Wake of a Circular Cylinder Using Unsteady Monopole Sources

1995 ◽  
Vol 117 (2) ◽  
pp. 227-233 ◽  
Author(s):  
Dartzi Pan ◽  
Yu-Chi Chin ◽  
Chih-Hao Chang
Keyword(s):  
Circular Cylinder ◽  
Flow Field ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Finite Volume Scheme ◽  
Cylinder Surface ◽  
Navier Stokes Equations ◽  
Laminar Wake ◽  
Lock In ◽  
Flux Difference

The vortex lock-in in the laminar wake behind a circular cylinder induced by the unsteady monopole source is numerically simulated in this paper. The artificial compressibility method is employed to solve the incompressible Navier-Stokes equations. A high-order accurate upwind flux-difference finite-volume scheme is used to discretize the flow field. The unsteady monopole source is simulated by a pulsating volume flux through the cylinder surface at a prescribed forcing frequency and amplitude. The forcing amplitude is set to a fixed value while the frequency is varied to search for the lock-in region. The flow field of the periodic lock-in state is examined in detail. Finally, the effects of a higher amplitude and a different source location are briefly investigated.

Stochastic low-dimensional modelling of a random laminar wake past a circular cylinder

2008 ◽  
Vol 606 ◽  
pp. 339-367 ◽  
Author(s):  
DANIELE VENTURI ◽  
XIAOLIANG WAN ◽  
GEORGE EM KARNIADAKIS
Keyword(s):  
Circular Cylinder ◽  
Turbulent Flows ◽  
Stokes Equations ◽  
Stochastic Simulations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Spatial Modes ◽  
Laminar Wake ◽  
Low Dimensional ◽  
Proper Orthogonal

We present a new compact expansion of a random flow field into stochastic spatial modes, hence extending the proper orthogonal decomposition (POD) to noisy (non-coherent) flows. As a prototype problem, we consider unsteady laminar flow past a circular cylinder subject to random inflow characterized as a stationary Gaussian process. We first obtain random snapshots from full stochastic simulations (based on polynomial chaos representations), and subsequently extract a small number of deterministic modes and corresponding stochastic modes by solving a temporal eigenvalue problem. Finally, we determine optimal sets of random projections for the stochastic Navier–Stokes equations, and construct reduced-order stochastic Galerkin models. We show that the number of stochastic modes required in the reconstruction does not directly depend on the dimensionality of the flow system. The framework we propose is general and it may also be useful in analysing turbulent flows, e.g. in quantifying the statistics of energy exchange between coherent modes.

The onset of oblique vortex shedding behind a heated circular cylinder in laminar wake regime

2012 ◽  
Vol 24 (1) ◽  
pp. 011701 ◽  
Author(s):  
Ming-Hsun Wu ◽  
Zdenăk Trávníček ◽  
An-Bang Wang
Keyword(s):  
Circular Cylinder ◽  
Vortex Shedding ◽  
Laminar Wake

Numerical Simulation and Stability Analysis of Laminar Wake Behind a Circular Cylinder

1998 ◽  
Vol 14 (4) ◽  
pp. 183-192
Author(s):  
Mei-Jiau Huang
Keyword(s):  
Circular Cylinder ◽  
Stokes Equations ◽  
Maximum Growth ◽  
Spectral Element ◽  
Navier Stokes ◽  
Stream Velocity ◽  
Navier Stokes Equations ◽  
Splitting Technique ◽  
Growth Criterion ◽  
Laminar Wake

ABSTRACTThe transition of a viscous incompressible laminar flow behind a circular cylinder from a steady state to its wake, counterpart at a Reynolds number Re = 100, based on the free stream velocity (U) and the cylinder diameter (D), is directly simulated. The two-dimensional unsteady Navier-Stokes equations are solved numerically by taking advantage of the splitting technique and the spectral element method. The main goal of this work is to explore the frequency-selection mechanism of the wake through the use of the absolute/convective instability theory, which in turn is performed by investigating the one-dimensional Orr-Sommerfeld equation. It is found that the predicted onset frequency based on the maximum-growth criterion is in a good agreement with the numerically observed one, although the measured growth rate is found smaller. The saturated frequencies predicted by the maximum-growth criterion and Kock's transition criterion are the same and also close to the measured one. More simulation or experimental data are needed for a further conclusion however.

Ultrastructural identification of three types of sensory setae on copepod antennae

1995 ◽  
Vol 53 ◽  
pp. 956-957
Author(s):  
T. M. Weatherby ◽  
P.H. Lenz
Keyword(s):  
Phase Locking ◽  
Membrane Surface ◽  
Reaction Times ◽  
High Sensitivity ◽  
Structural Features ◽  
Calanoid Copepods ◽  
Marine Food Webs ◽  
Dendritic Membrane ◽  
Ultrastructural Characterization

Crustaceans, as well as other arthropods, are covered with sensory setae and hairs, including mechanoand chemosensory sensillae with a ciliary origin. Calanoid copepods are small planktonic crustaceans forming a major link in marine food webs. In conjunction with behavioral and physiological studies of the antennae of calanoids, we undertook the ultrastructural characterization of sensory setae on the antennae of Pleuromamma xiphias.Distal mechanoreceptive setae exhibit exceptional behavioral and physiological performance characteristics: high sensitivity (<10 nm displacements), fast reaction times (<1 msec latency) and phase locking to high frequencies (1-2 kHz). Unusual structural features of the mechanoreceptors are likely to be related to their physiological sensitivity. These features include a large number (up to 3000) of microtubules in each sensory cell dendrite, arising from or anchored to electron dense rods associated with the ciliary basal body microtubule doublets. The microtubules are arranged in a regular array, with bridges between and within rows. These bundles of microtubules extend far into each mechanoreceptive seta and terminate in a staggered fashion along the dendritic membrane, contacting a large membrane surface area and providing a large potential site of mechanotransduction.

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