Numerical Study of the Laminar Flow Past a Rotating Square Cylinder at Low Spinning Rates

Chatterjee, Dipankar; Gupta, Satish Kumar

doi:10.1115/1.4028500

Cited by 17 publications

(6 citation statements)

References 27 publications

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“…This two-dimensional unsteady flow persists until Re≈189 where the three-dimensional mode-A small-scale structures are observed [3]. The flow separation and transition can also be caused by the cylinder oscillation or rotation [4][5][6][7].…”

Section: Introductionmentioning

confidence: 94%

Effect of Corner Radius in Stabilizing the Low-Re Flow Past a Cylinder

Zhang

Samtaney

2017

Journal of Fluids Engineering

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We perform global linear stability analysis on low-Re flow past an isolated cylinder with rounded corners. The objective of the present work is to investigate the effect of cylinder geometry (corner radius) on the stability characteristics of the flow. Our investigation sheds light on new physics that the flow can be stabilized by partially rounding the cylinder in the critical and weakly supercritical flow regimes. The flow is first stabilized and then gradually destabilized as the cylinder varies from square to circular geometry. The sensitivity analysis reveals that the variation of stability is attributed to the different spatial variation trends of the backflow velocity in the near- and far-wake regions for various cylinder geometries. The results from the stability analysis are also verified with those of the direct simulations, and very good agreement is achieved.

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Section: Introductionmentioning

confidence: 94%

Effect of Corner Radius in Stabilizing the Low-Re Flow Past a Cylinder

Zhang

Samtaney

2017

Journal of Fluids Engineering

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“…To avoid the effect of transience of the flow initiation, each case was simulated for at least 20 cycles to obtain asymptotically cyclic results before analyzing them. Chatterjee and Gupta (2015) and Singh et al (2009) have studied the problems of only rotating and only translating square cylinder respectively. To the best of our knowledge there is no past work that studies drag signals and flow fields for a square undergoing combined rotational and transverse oscillation.…”

Section: Resultsmentioning

confidence: 99%

“…Ohba and Kuroda (1993) provided force coefficient signals, surface pressure distribution and flow visualizations for rotating square at high Re and low angular velocities. Chatterjee and Gupta (2015) identified suppression of shedding beyond a critical angular velocity along with drag suppression and lift enhancement for a rotating square cylinder. The change in vortex structures when the square is rotated impulsively was studied numerically (1 ≤ 𝑅𝑒 ≤ 300) by De-Ming and Jian-Zhong (2010).…”

Section: Introductionmentioning

confidence: 94%

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Laminar Flow over a Square Cylinder Undergoing Combined Rotational and Transverse Oscillations

2021

JAFM

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This work numerically investigates the effects of combined rotational and transverse oscillations of a square cylinder on the flow field and force coefficients. The primary non-dimensional parameters that were varied are frequency ratio fR (0.5, 0.8), Re (50-200), phase difference (ϕ) between the motions and rotational amplitude (θ0) with the influence of the last three parameters being discussed in detail. The amplitude of transverse oscillations is fixed at 0.2D, where D is the cylinder width. The study has been validated using the mean drag coefficient for stationary and transversely oscillating square cylinders from literature. Output data was obtained in the form of force coefficient (Cd), vorticity and pressure contours. The governing equations for the 2dimensional model were solved from an inertial frame of reference (overset meshing) using finite volume method. The interplay between the convective field and prescribed motion has been used to explain many of the results obtained. The relative dominance of cylinder motion over the flow stream was determined using Discrete Fast Fourier Transform. The influence of Re on Cd disappears when the motions are completely out of phase (ϕ = π). In general, the Cd for low Re flows exhibited low sensitivity to change in other parameters. Direct correlation has been observed between frontal area, vortex patterns and drag coefficient

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“…2009; He, Li & Wang 2014), surface roughness (van Hinsberg, Schewe & Jacobs 2018), and so on. Active control methods, which need extra energy supply, include but are not limited to, rotation (Chatterjee & Gupta 2015 a , b ), oscillation (Bearman & Obasaju 1982; Fu et al. 2017), plasma actuator (Anzai et al.…”

Section: Introductionmentioning

confidence: 99%

Effect of excitation frequency on flow characteristics around a square cylinder with a synthetic jet positioned at front surface

Wang

Feng

et al. 2019

J. Fluid Mech.

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The flow over a square cylinder controlled by a slot synthetic jet positioned at the front surface is investigated experimentally at different excitation frequencies. The Reynolds number based on the free-stream velocity and the side length of the square cylinder is 1000. The flow visualization was conducted using the laser-induced fluorescence technique. The velocity fields upstream and downstream of the square cylinder were measured synchronously with the two-dimensional time-resolved particle image velocimetry technique. Both the evolution of vortex structures and the characteristic frequencies of upstream and downstream flow fields are presented. The flow dynamics vary significantly with the excitation frequency at a fixed stroke length. During one excitation cycle, the synthetic jet vortex pair deflects to one side and later swings to the other side at a quite small excitation frequency of $f_{e}/f_{0}=0.6$, while it only deflects toward one side and does not turn to the other side at $f_{e}/f_{0}=1.0$. Compared with the natural case, the wake characteristics for the above two cases are not changed much by the synthetic jet adopted. At a moderate excitation frequency of $f_{e}/f_{0}=2.0$, the synthetic jet deflects upwards and downwards alternatively. The upstream flow field has a dominant frequency identical to half of the excitation frequency. Under the perturbations of the synthetic jet, two wake vortex pairs are formed per shedding cycle with a shedding frequency equal to that of the square cylinder without control. At a higher excitation frequency of $f_{e}/f_{0}=3.4$, the synthetic jet keeps deflecting to one side, and the upstream flow field is governed by the excitation frequency. The flow separation on the deflected side is suppressed effectively, and no periodic vortex shedding can be observed in the wake. Statistically, the velocity profiles also change with control. The recirculation bubble length in the wake is shortened, and the time-averaged velocity fluctuation is weakened remarkably. The control effects of the synthetic jet and the continuous jet are compared in this paper when placed at the front surface of a square cylinder.

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Numerical Study of the Laminar Flow Past a Rotating Square Cylinder at Low Spinning Rates

Cited by 17 publications

References 27 publications

Effect of Corner Radius in Stabilizing the Low-Re Flow Past a Cylinder

Effect of Corner Radius in Stabilizing the Low-Re Flow Past a Cylinder

Laminar Flow over a Square Cylinder Undergoing Combined Rotational and Transverse Oscillations

Effect of excitation frequency on flow characteristics around a square cylinder with a synthetic jet positioned at front surface

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