Strouhal numbers of inclined flat plates

Chen, Jerry M.; Fang, Y. C.

doi:10.1016/0167-6105(96)00044-x

Cited by 83 publications

(38 citation statements)

References 10 publications

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“…However, as the velocity increases, and as the feather begins to flutter as a result of the forces induced by the shedding of vortices, it will produce a wider wake. It has been found that the frequency of vortex shedding with wake w is given by the expression: where w is the width of the wake and the Strouhal number is 0.16 (Chen and Fang, 1996). Therefore the wake frequency should rise rather more slowly with velocity, as the wake width increases at higher speeds as the amplitude of flutter rises.…”

Section: Discussionmentioning

confidence: 99%

“…where v is the airspeed, d the chord length of the plate, and St is the Strouhal number, which for plates parallel to flow is approximately 0.8 (Chen and Fang, 1996). For our feathers, with their mean chord of 14.7mm, at the speed of 12ms -1 when the feather is just starting to flutter, vortices would therefore be shed at around 650Hz.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Sonation in the male common snipe (Capella gallinago gallinagoL.) is achieved by a flag-like fluttering of their tail feathers and consequent vortex shedding

Casteren

Codd

Gardiner

et al. 2010

Journal of Experimental Biology

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SUMMARYMale common snipe (Capella gallinago gallinago) produce a 'drumming' sound with their outer tail feathers during their mating dives, but little is known about how this is achieved. We investigated the movements and sound producing capabilities of the outer tail feathers. Using a wind tunnel, we compared observations of the frequencies of sound produced with the predictions from aerodynamic theory. The feathers were also filmed in an air-flow with a high speed video camera, and subjected to morphological examination and biomechanical testing. We propose a mechanistic hypothesis of how the modified outer feathers of the male common snipe generate sound, and the adaptations that facilitate this. Video and audio analysis of the feather demonstrated that a fluttering of the trailing vane generated the sound. The flutter of the vane is facilitated by the rearward curvature of the feather shaft, reduced branching angles of the barbs in the trailing vane and the lack of hooks on the barbs along a hinge region, all of which increase its flexural compliance. Sound production occurred at the same frequency as the vane movements, at frequencies consistent with it being produced by a fluttering flag mechanism powered by vortex shedding. Supplementary material available online at

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Sonation in the male common snipe (Capella gallinago gallinagoL.) is achieved by a flag-like fluttering of their tail feathers and consequent vortex shedding

Casteren

Codd

Gardiner

et al. 2010

Journal of Experimental Biology

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“…According to the box plot, lower Fr values will make the plate fly higher and will reduce the dispersion. As Fr is only present in (12), the result dispersion is caused by the plate rotation. We should recall that Fr is the dimensionless length of the plate; = 1/Fr 2 .…”

Section: Plate Trajectories Databasementioning

confidence: 99%

“…However, high fidelity models allow the computation of the trajectory of any kind of shape and do not require experimental databases or correlations for aerodynamic forces and moments. Also, high fidelity models take into account Reynolds number effects and lift and drag fluctuations (10% to 20%) caused by vortex shedding [11,12] in the case of flow separation around debris. Both models are complementary and need research developments to better assess the risk of impacts.…”

Section: Introductionmentioning

confidence: 99%

Parametric Studies of Flat Plate Trajectories Using VIC and Penalization

Morency

Beaugendre

2018

Modelling and Simulation in Engineering

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Flying debris is generated in several situations: when a roof is exposed to a storm, when ice accretes on rotating wind turbines, or during inflight aircraft deicing. Four dimensionless parameters play a role in the motion of flying debris. The goal of the present paper is to investigate the relative importance of four dimensionless parameters: the Reynolds number, the Froude number, the Tachikawa number, and the mass moment of inertia parameters. Flying debris trajectories are computed with a fluid-solid interaction model formulated for an incompressible 2D laminar flow. The rigid moving solid effects are modelled in the NavierStokes equations using penalization. A VIC scheme is used to solve the flow equations. The aerodynamic forces and moments are used to compute the acceleration and the velocity of the solid. A database of 64 trajectories is built using a two-level full factorial design for the four factors. The dispersion of the plate position at a given horizontal position decreases with the Froude number. Moreover, the Tachikawa number has a significant effect on the median plate position.

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“…The timescale associated with shedding von Karman vortices from the moving plate, t shed , can be estimated from the Strouhal number, St, and dimensions of the plate as in Equation 2. The Strouhal number is relatively constant when computed using the projected thickness of the plate, 16 w p , which is a function of its chord-length and thickness ratio, d. Together, these yield a number of dimensionless parameters under the experimenter's control: Re, S, T , t accel /t heave , and d.…”

Section: Theorymentioning

confidence: 99%