Experiments on the aerodynamic behaviour of square cylinders with rounded corners at Reynolds numbers up to 12 million

Hinsberg, Nils Paul van; Schewe, G.; Jacobs, Markus

doi:10.1016/j.jfluidstructs.2017.08.002

Cited by 36 publications

(15 citation statements)

References 27 publications

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“…The results of C 0 L are shown in Figure 12(c). C 0 L goes down severely when Re increases from the subcritical region to the critical region, which is nearly identical to the results of Schewe (1983) andVan Hinsberg et al (2017). Moreover, the TI of the oncoming flow also has a significant effect on C 0 L of a cylinder with rounded corners.…”

Section: Reynolds Number Effectsupporting

confidence: 82%

“…In particular, the critical Re reduces from 1.42 × 10 6 to about 2.00 × 10 5 with an increase in r/b from 0.08 to 0.5 (circular cylinder), as highlighted by a red arrow in Figure 12(a). Meanwhile, C D in the subcritical Re regime drops from 1.6 to 1.2 (Polhamus, 1958; Schewe, 1983; Van Hinsberg et al, 2017). Note that the TI of the oncoming flow also plays an important role in the variation of C D , as shown in Figure 12(a).…”

Section: Resultsmentioning

confidence: 99%

“…Note that the TI of the oncoming flow also plays an important role in the variation of C D , as shown in Figure 12(a). Generally, a higher TI results in a smaller critical Re and lower value of C D (Carassale et al, 2014; Van Hinsberg et al, 2017). For the present train model, a clear drag crisis is also observed with C D reducing sharply from 1.70 to 1.29 in the Re range of 9.35 × 10 4 –2.49 × 10 5 , as shown in Figure 12(a).…”

Section: Resultsmentioning

confidence: 99%

“…They found that as r/b increases, rounded corners lead to elongated but attenuated wake vortices, and the formation length of the first roll-up vortex reaching its maximum at r/b = 0.125, but the effects of r/b on the ratio of vortex wavelength to vortex lateral spacing are very limited. Similar to the circular cylinder, the flow around a cylinder with rounded corners exhibits strong Reynolds number dependence (Carassale et al, 2014; Polhamus, 1958; Schewe, 1983; Van Hinsberg et al, 2017). Within r/b = [0.08, 0.5], the critical Re , corresponding to the transition from subcritical to critical regimes and also the start of the well-known drag crisis, decreases from 1.42 × 10 6 to 2.0 × 10 5 .…”

Section: Introductionmentioning

confidence: 99%

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Aerodynamics of a two-dimensional bluff body with the cross-section of a train

Wang

et al. 2020

Advances in Structural Engineering

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Experiments on the aerodynamics of a two-dimensional bluff body simplified from a China high-speed train in crosswinds were carried out in a wind tunnel. Effects of wind angle of attack α varying in [−20°, 20°] were investigated at a moderate Reynolds number Re = 9.35 × 104 (based on the height of the model). Four typical behaviors of aerodynamics were identified. These behaviors are attributed to the flow structure around the upper and lower halves of the model changing from full to intermittent reattachment, and to full separation with a variation in α. An alternate transition phenomenon, characterized by an alteration between large- and small-amplitude aerodynamic fluctuations, was detected. The frequency of this alteration is about 1/10 of the predominant vortex shedding. In the intervals of the large-amplitude behavior, aerodynamic forces fluctuate periodically with a strong span-wise coherence, which are caused by the anti-symmetric vortex shedding along the stream-wise direction. On the contrary, the aerodynamic forces fluctuating at small amplitudes correspond to a weak span-wise coherence, which are ascribed to the symmetric vortex shedding from the upper and lower halves of the model. Generally, the mean amplitude of the large-amplitude mode is 3 times larger than that of the small one. Finally, the effects of Reynolds number were examined within Re = [9.35 × 104, 2.49 × 105]. Strong Reynolds number dependence was observed on the model with two rounded upper corners.

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Section: Reynolds Number Effectsupporting

confidence: 82%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Aerodynamics of a two-dimensional bluff body with the cross-section of a train

Wang

et al. 2020

Advances in Structural Engineering

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“…However, both the flow topology around and the aerodynamic loading on these structures are now distinct functions of the angle of incidence [3,4,7,8]. A one-sided flow reattachment of the separated shear layer takes place above the critical angle of incidence of about ±13 • [4,12] that leads to a clear asymmetric flow field around the prism and the appearance of a distinct steady lift force.…”

Section: Introductionmentioning

confidence: 99%

Loading on rounded square foundation elements of offshore structures with marine growth at incidence

Frede¹,

Hinsberg²

2020

Australasian Fluid Mechanics Conference (AFMC)

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A systematic wind tunnel study is performed to identify the mean and fluctuating loads experienced by a 2D square prism with non-dimensional rounded edges of r/D = 0.16 and covered with hard marine fouling for Reynolds numbers between 70,000 and 8 million. The incidence angle is varied from α = −45 • to 3.25 • with increments of 3.25 • and 6.5 • . The critical angle of incidence, at which a reattachment of the free shear layer takes place on the lateral windward directed side surface, is found at α cr = −6.5 • . For α < α cr two opposite trends -governed by the Reynolds number -of the mean drag coefficient, the r.m.s. of the lift fluctuations, and the Strouhal number are obtained. On the contrary, all aerodynamic parameters are relatively Reynolds-number independent for α > α cr . For the latter angles of incidence, a decrease towards −45 • induces higher values of C D and the r.m.s. of the lift fluctuations, as well as lower Strouhal numbers and mean lift forces.

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The Reynolds-Number Effect on the Steady and Unsteady Aerodynamic Loading on Smooth and Slightly-Rough Square-Section Cylinders with Rounded Corners

Hinsberg¹

2019

Notes on Numerical Fluid Mechanics and Multidisciplinary Design

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Experiments on the aerodynamic behaviour of square cylinders with rounded corners at Reynolds numbers up to 12 million

Cited by 36 publications

References 27 publications

Aerodynamics of a two-dimensional bluff body with the cross-section of a train

Aerodynamics of a two-dimensional bluff body with the cross-section of a train

Loading on rounded square foundation elements of offshore structures with marine growth at incidence

The Reynolds-Number Effect on the Steady and Unsteady Aerodynamic Loading on Smooth and Slightly-Rough Square-Section Cylinders with Rounded Corners

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