Observations on the Near Wake of a Yawed Circular Cylinder

Lourenco, L.; Shih, C.; Krothapalli, A.

doi:10.1007/978-3-662-02885-8_17

Cited by 23 publications

(27 citation statements)

References 2 publications

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“…The squares are experimental results. The near wake parts are from Lourenco et al [23] while the last four points in the far wake are from Ong et al [24] worse than the one from the B-spline scheme. The reason is that we use a second order finite difference scheme while the B-spline scheme is of higher-order.…”

Section: Turbulent Flow Around a Circular Cylinder Atmentioning

confidence: 96%

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Large-eddy simulation of circular cylinder flow at subcritical Reynolds number: Turbulent wake and sound radiation

Guo

Zhang

2015

Acta Mech. Sin.

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The flows past a circular cylinder at Reynolds number 3900 are simulated using large-eddy simulation (LES) and the far-field sound is calculated from the LES results. A low dissipation energy-conserving finite volume scheme is used to discretize the incompressible NavierStokes equations. The dynamic global coefficient version of the Vreman's subgrid scale (SGS) model is used to compute the sub-grid stresses. Curle's integral of Lighthill's acoustic analogy is used to extract the sound radiated from the cylinder. The profiles of mean velocity and turbulent fluctuations obtained are consistent with the previous experimental and computational results. The sound radiation at far field exhibits the characteristic of a dipole and directivity. The sound spectra display the −5/3 power law. It is shown that Vreman's SGS model in company with dynamic procedure is suitable for LES of turbulence generated noise.

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Section: Turbulent Flow Around a Circular Cylinder Atmentioning

confidence: 96%

“…The SGS model used in these two simulations was the dynamic Smagorinsky model. The experimental data for the vortex-formation region is from the particle image velocimetry (PIV) result of Lourenco et al [23]. The near wake result is from Ong and Wallace [24] in which the hot-wire velocimetry was used.…”

Section: Turbulent Flow Around a Circular Cylinder Atmentioning

confidence: 99%

Large-eddy simulation of circular cylinder flow at subcritical Reynolds number: Turbulent wake and sound radiation

Guo

Zhang

2015

Acta Mech. Sin.

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“…Figure 9 shows the streamwise velocity component along the vertical section located 1.06 D behind the cylinder. For lower Re (= 3900 37 ), L r is higher (1.5 D ), and the velocity minima is higher at a given x location, whereas for higher Re (= 140,000 29 ), L r and the velocity minima is lower at the same x location. In the present work, the value of Re (= 19,800) lies between 3900 and 140,000, and as a result, the velocity minima also lie in between.…”

Section: Resultsmentioning

confidence: 91%

Aerodynamic noise from long circular and non-circular cylinders using large eddy simulations

Jacob

Bhattacharya

2022

International Journal of Aeroacoustics

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Flow-induced aerodynamic noise from four cylindrical shapes of infinite length at a low subcritical flow regime is studied using Large Eddy Simulation (LES) and acoustic analogy. Numerical simulations are performed for short-span (length to diameter ratio of 3) cylinders, and a sound correction method based on equivalent/spatial coherence length has been applied to estimate noise from long-span cylinders. An attempt is made to compare spatial coherence lengths of four cross-sections at the same Reynolds number (Re). The sound correction method that is well established for circular cylinders proved effective for non-circular cross-sections also. Owing to the limitation in computational capacity, a well-resolved LES is still unachievable for higher Re flows and long-span cylinders without adopting a sound correction methodology. A grid resolution based on the characteristic length and velocity scale was adopted in simulation and proved effective for computing aerodynamic and aeroacoustic characteristics. An ‘effective frequency band’ of sound pressure level-frequency curve is proposed that predicts over 99.5% of the overall sound pressure level, and features of this band for four cross-sections are presented.

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“…On the other hand, laminar, SST Kv and SKe models gave totally irrelevant results. (Wornom et al, 2011) 0.99 Experiment (Lourenco et al, 1992) 0.985 Experiment (Breuer, 1998) 1.08 Experiment (Chen and Ballengee, 1971) 0.38 0.47 Experiment (Keefe, 1962) 0.38 Experiment (Schlichting and Gersten, 1979) 0.995 1.1 For the lift coefficient, by comparing the achieved results (Table 4) with the result from Keefe (1962) which is 0.38, it found that SKv is the best turbulence model out of the tested group to predict the lift coefficient at 0.35 with 8% error while RKe came as a close second at 0.26 with 26%. On the other hand, laminar, SST kv and SKe gave totally irrelevant results.…”

Section: Numerical Model Validation and Resultsmentioning

confidence: 99%

Theoretical and numerical analysis of vortex bladeless wind turbines

Elsayed

Farghaly

2022

Wind Engineering

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Wind energy is one of the most abundant renewable energy resources that have been used to generate electricity. A new used method called Vortex Bladeless Wind Turbines which is basically a rod oscillating and vibrating in response to the vortices originating from the wind passing by the rod. This paper presents a mathematical model used in analysis the work of the VBWT. A prototype design was be created using solidwork to calculate the physical properties. In addition, a numerical study was carried out using Ansys software to calculate the forces affecting the VBWT. Finally, the safety of VBWT structure is studied. The results indicated that, the obtained model can be applied practically in studying the performance of general VBWT with low wind speed, as VBWT use less space, low maintenance and hence economical. The mathematical formula of VBWT power is function of air velocity, aerodynamic coefficients, and prototype physical properties.

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Observations on the Near Wake of a Yawed Circular Cylinder

Cited by 23 publications

References 2 publications

Large-eddy simulation of circular cylinder flow at subcritical Reynolds number: Turbulent wake and sound radiation

Large-eddy simulation of circular cylinder flow at subcritical Reynolds number: Turbulent wake and sound radiation

Aerodynamic noise from long circular and non-circular cylinders using large eddy simulations

Theoretical and numerical analysis of vortex bladeless wind turbines

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