Finite mixture model applied in the analysis of a turbulent bistable flow on two parallel circular cylinders

Paula, Alexandre Vagtinski de; Möller, Sérgio Viçosa

doi:10.1016/j.nucengdes.2013.02.029

Cited by 11 publications

(11 citation statements)

References 27 publications

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“…The experimental study was performed in one of the aerodynamic channels of the Fluid Mechanics Laboratory of the Federal University of Rio Grande do Sul. The aerodynamic channel used in the measurements is the same presented in de Paula and Möller [9], as shown in Fig. 2, which is a 900-mm-long rectangular channel, with 146 mm height and a width of 193 mm.…”

Section: Experimental Methodologymentioning

confidence: 99%

“…Data acquisition was performed with two different sampling frequencies: 1 kHz, with a low pass filter at 0.3 kHz and 3 kHz with a low pass filter at 1 kHz. Probe location is chosen based on results from flow visualization, so that, the flow emanating from the gap between cylinders reaches the probe (e.g., [9,12].…”

Section: Experimental Methodologymentioning

confidence: 99%

“…The experimental work started with the measurements of velocity and velocity fluctuations after the screens to obtain velocity and turbulence intensity profiles used as boundary conditions at the inlet numerical domain, leading to uniform velocity profiles of 13.45 m/s and a turbulence intensity of 0.6%. The resulting Reynolds number, based on the cylinder diameter was Re D = 2.2 × 10 4 , same as [9].…”

Section: Experimental Methodologymentioning

confidence: 99%

“…Based on Olinto's observations, de Paula and Möller [9] showed that the study of the behavior of the flow in simplified geometries, as in the case of two tubes placed sideby-side, can help the comprehension of the parameters and variables that influence more complex geometries, as in the case of tube banks.…”

Section: Introductionmentioning

confidence: 99%

“…de Paula and Möller [9] presented an experimental study with probability density functions and a doublewell energy model to evaluate the wake changes on a flow over two side-by-side cylinders, showing the presence of two major states of energy, corresponding to the two flow modes, with evidences of a third flow mode.…”

Section: Introductionmentioning

confidence: 99%

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Characteristics of the wake formation and force distribution of the bistable flow on two cylinders side-by-side

Neumeister

Petry

Möller

2018

J Braz. Soc. Mech. Sci. Eng.

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This numerical study with experimental support examines the bistable phenomenon along two parallel smooth cylinders submitted to a uniform turbulent cross-flow. The spacing ratio P/D of the cylinders is 1.26, being D the cylinder diameter and P the distance between centers. The computational domain and the experimental tests section are equivalents. The Reynolds number based on the free mean velocity and cylinder diameter was Re = 2.2 × 10 4. For the numerical analysis, the Navier-Stokes equations were solved using finite volumes method for a URANS simulation (unsteady Reynolds averaged Navier-Stokes) with the kω-SST-SAS (shear stress tensor-scale adaptive simulation) turbulence model. Measurements were performed by means of hot wire anemometry technique, firstly to determine actual boundary conditions of flow velocity and turbulence intensity at the test section entrance, secondly to obtain velocity and velocity fluctuation at the wake of the cylinders in different positions along the cylinder height to corroborate the numerical results. By means of the numerical results of velocity, the process of the wake formation is described, showing that the bistability does not occur simultaneously along the cylinder, corroborated by a delay on the switching process of the simultaneously measured velocities and the cross-correlation function. This effect appears also in the results of cylinder wall pressure distribution as well as in lift and drag coefficients. Keywords Turbulent flow • Bistability • Two cylinders side-by-side • URANS simulation • Hot wires List of symbols A Area (m 2) C D Drag coefficient C L Lift coefficient C ′ D Drag coefficient fluctuation C ′ L Lift coefficient fluctuation D Cylinder diameter (m) GCI Grid convergence index ρ Density (kg/m 3) p Mean pressure (Pa) P Distance between cylinders (pitch) (m) P/D Pitch-to-diameter ratio Re Reynolds number, Re D = VD St Strouhal number, St = fD V t Time (s) x Axis direction x y Axis direction y z Axis direction z

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Section: Experimental Methodologymentioning

confidence: 99%

Section: Experimental Methodologymentioning

confidence: 99%

Section: Experimental Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Characteristics of the wake formation and force distribution of the bistable flow on two cylinders side-by-side

Neumeister

Petry

Möller

2018

J Braz. Soc. Mech. Sci. Eng.

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On the interaction of the wake flow with the rotation process of two parallel free-to-rotate cylinders submitted to an accelerating flow

et al. 2022

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Wake behavior analysis for two circular cylinders placed at several angles to the flow

Habowski

Paula

Möller

2020

J Braz. Soc. Mech. Sci. Eng.

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This paper presents an experimental study performed in an aerodynamic channel using hot-wire anemometers and flow visualization by injection of dye in water in a hydraulic channel of the flow on two rigid cylinders placed at several angular positions to the flow, from 0° (side-by-side) to 90° (tandem). The main objective is to analyze the effects of the angular positions on the wake flow and the occurrence of bistability. Signal analysis was performed by means of Fourier and discrete and continuous wavelets transform. Time series of the angle of the flow emanating from the cylinder gap related to the main flow direction were obtained from flow visualization analysis to track the flow mode change in the water flow. Results from the aerodynamic channel showed the presence of bistability only for side-by-side configuration, and some attempts to modify the flow mode for 2.5° and 5° while through the flow visualization the flow mode changes were present for side-by-side and for 2.5° configurations. For the other angles investigated, the presence of a narrow and a wide wake without flow mode changes was observed. The difference between the results for 2.5° suggests that the scales and inertia involved in bistability phenomenon may affect the phenomenon. For 75°, the wide wake is so vigorous that it overwhelmed the narrow wake, displacing it downwards, and increasing the amplitude of the vertical component of the wake compared to smaller angles. The phenomena analyzed can be seen as two-dimensional for all cases, but the presence of vertical components shows that the resulting flow is three-dimensional. Keywords Bistable flow • Flow visualization • Hot wires • Turbulent flow • Wavelets List of symbols a,b Wavelet parameters B e Bandwidth (Hz) CWT Constant wavelet transform (-) d Cylinder diameter (mm) Db20 Daubechies wavelet

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Finite mixture model applied in the analysis of a turbulent bistable flow on two parallel circular cylinders

Cited by 11 publications

References 27 publications

Characteristics of the wake formation and force distribution of the bistable flow on two cylinders side-by-side

Characteristics of the wake formation and force distribution of the bistable flow on two cylinders side-by-side

On the interaction of the wake flow with the rotation process of two parallel free-to-rotate cylinders submitted to an accelerating flow

Wake behavior analysis for two circular cylinders placed at several angles to the flow

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