The effect of the chamfered-corner ratio on the characteristics of the wake behind a square and a 2:1 rectangular section model: PIV measurements and POD analysis

IF 2.8 2区工程技术 Q2 ENGINEERING, MECHANICAL Experimental Thermal and Fluid Science Pub Date : 2025-03-09 DOI:10.1016/j.expthermflusci.2025.111470

Chin-Chen Chou, Kuan-Zu Lee, Cheng-Yang Chung, Kung-Ming Chung

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引用次数: 0

Abstract

Corner-chamfering influences flow characteristics around a 2-dimensional prism to mitigate wind load and wind-induced responses; the side ratio is also an important parameter. This study determines the effect of a corner chamfer on the wake from a 2-dimensional prism (B/D = 1) and a rectangular cross-sectional model for which B/D = 2, where B is the width and D is the height. The effect of the chamfer ratio (C/D, where C represents the length of the chamfer corner) on the leading edge of a models is determined in terms of flow characteristics. The wake strength and the structural integrity of the model are also affected by the chamfer corner ratio.

Velocity and vortex fields are created using Particle Image Velocimetry (PIV) measurements in a wind tunnel for Re = 1.05 × 10⁴. The results show that the mean and the root-mean-square (RMS) velocity coefficients and the turbulent kinetic energy (TKE) in wake region are affected by the value of C/D. The Strouhal number (St) increases as the value of C/D increases for a model for which B/D = 2. The formation length (L_F) increases for a model for which B/D is 1 if corners are chamfered and L_F decreases for a model for which B/D is 2. Chamfered corners can increase vortex shedding frequency for a model for which B/D is 1 and 2.

The velocity component is the input data for proper orthogonal decomposition (POD). POD mode analysis shows that, for a model for which B/D = 1, the energy of the dominant modes increases with C/D but for a model for which B/D = 2, the energy of the dominant modes decreases as C/D increases. The distribution of temporal coefficients (

a_{1}

and

a_{2}

) for a model for which B/D = 1 that has no chamfered corners resembles a sine wave, which is more stable than the distribution for a model with chamfered corners. As C/D increases, the distribution for a₁ and a₂ for a model for which B/D = 2 gradually become stable, so vortex shedding is symmetrical.

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来源期刊

Experimental Thermal and Fluid Science 工程技术-工程：机械

CiteScore

6.70

自引率

3.10%

发文量

159

审稿时长

34 days

期刊介绍： Experimental Thermal and Fluid Science provides a forum for research emphasizing experimental work that enhances fundamental understanding of heat transfer, thermodynamics, and fluid mechanics. In addition to the principal areas of research, the journal covers research results in related fields, including combined heat and mass transfer, flows with phase transition, micro- and nano-scale systems, multiphase flow, combustion, radiative transfer, porous media, cryogenics, turbulence, and novel experimental techniques.