3D Visualization of the separated fluid flows

Gushchin, V. A.; Kostomarov, A.V.; Matyushin, P. V.

doi:10.1007/bf03181587

Cited by 29 publications

(15 citation statements)

References 10 publications

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“…HTFF 116-2 [6] shows that for Reynolds number greater than 200, the dimensionless vortex shedding frequency is around 0.21, while the numerical study of Gushchin et al [7] shows that for spheres this frequency is lower.…”

Section: Introductionmentioning

confidence: 96%

The Reynolds Stresses Equation Modelling in the Prediction of Flow Past a Rotating Cylinder at High Reynolds Number

Iacovides¹,

Craft²,

Ruchayosyothin³

2017

World Congress on Mechanical, Chemical, and Material Engineering

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-This research presents the predictions of flow past a rotating cylinder at a subcritical Reynolds number of 130,000. The main objective is to identify turbulence effective modelling strategies for unsteady RANS computations. For this reason both effectiveviscosity and stress-transport models have been used with different strategies for the modelling of near-wall turbulence which include standard log-law-based, and more refined wall functions, the latter based on the analytical solution of 1-D equations for the transport of wall-parallel momentum. The models' effectiveness is assessed through comparisons with available experimental and Large Eddy Simulation (LES) data. It is important that these present studies are in a good agreement with those obtained by the decreasing drag coefficient and increasing lift coefficient when a spin ratios ( : proportional tangential velocity of the cylinder wall to inlet flow velocity) of a cylinder grow up. Moreover, the stability of the flow domain is well improved with the suppressed vortex shedding, as well. Significantly, the prediction of the position of stagnation and separation flow position correspond to the magnitude of lift, drag coefficient and the rotation direction. Overall, this research has confirmed that the RSMs is capable to examine the external flow and more sensitized on the curvature surface flow.

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Section: Introductionmentioning

confidence: 96%

The Reynolds Stresses Equation Modelling in the Prediction of Flow Past a Rotating Cylinder at High Reynolds Number

Iacovides¹,

Craft²,

Ruchayosyothin³

2017

World Congress on Mechanical, Chemical, and Material Engineering

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show abstract

“…However, these studies have not analyzed completely the whole wake including recirculating zone but done only a simple investigation on the flow features in the far wake. It is necessary to have a systematic approach (Gushchin et al, 2004;Calluaud et al, 2005) in the aspect of three-dimensional vortex structures because the safety as well as the fuel consumption rate in driving a road vehicle is determined to a great extent by the highly three-dimensional flow characteristics around that.…”

Section: Introductionmentioning

confidence: 99%

Effects of an air spoiler on the wake of a road vehicle by PIV measurements

Kim

Sung

et al. 2006

J Vis

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A particle image velocimetry (PIV) technique has been used to analyze the flow characteristics behind a road vehicle with/without an air spoiler attached on its trunk and also to estimate its effect on the wake. A vehicle model scaled in the ratio of 1/43 is set up in the mid-section of a closed-loop water tunnel. The Reynolds number based on the vehicle length is 10 5 . To investigate the three-dimensional structure of the recirculation zone and vortices, measurements are carried out on the planes both parallel and perpendicular to the free stream, respectively. The results show significantly different vorticity distributions in the recirculation region according to the existence of the air spoiler. The focus and the saddle point, appearing in the wake, are disposed differently along the spanwise direction. Regarding the streamwise vortices, the air spoiler produces large wing tip vortices. They have opposite rotational directions to C-pillar vortices which are commonly observed in the case that an air spoiler is absent. The wing tip vortices generate the down force and as a result, they might make the vehicle more stable in driving.

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“…Frequently, this constitutes a major issue in the automation of feature extraction and it also determines the eventual success or failure of subsequent higher level processes such as classification, analysis and visualization (e.g., Gushchin et al, 2004;Vénere et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Application of color image segmentation to estrusc detection

Fresno

Macchi

Marti

et al. 2006

J Vis

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Automatic segmentation and classification of color images is a problem of great practical interest in different areas. This paper presents an algorithm for this purpose which is divided in three steps. Firstly, the regions of interest are isolated from the rest of the image based on threshold functions defined in the YUV and YIQ color spaces, producing a set of connected components. Then, a set of features is computed to enable a quantitative evaluation of the segmented objects. Finally, the image is classified by means of a decision rule based on the analysis of the differences between the computed measures and a set of ideally segmented images, according to experts' assessment. The algorithm was applied to a decision support tool for estrus detection in cattle. This approach constitutes a valuable alternative to improve this process, as it may replace the visual observation by the automatic analysis of pictures taken to cows in controlled environments. Experimental results show that the segmentations obtained with this method are highly satisfactory and they allow a precise classification of the images with low computational complexity.

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3D Visualization of the separated fluid flows

Cited by 29 publications

References 10 publications

The Reynolds Stresses Equation Modelling in the Prediction of Flow Past a Rotating Cylinder at High Reynolds Number

The Reynolds Stresses Equation Modelling in the Prediction of Flow Past a Rotating Cylinder at High Reynolds Number

Effects of an air spoiler on the wake of a road vehicle by PIV measurements

Application of color image segmentation to estrusc detection

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