Drag reduction effect of square cylinders by grooves and corner-cuttings

Koide, Masakazu; Okanaga, Hiroo; Aoki, Katsumi

doi:10.3154/jvs.26.supplement1_69

Cited by 3 publications

(3 citation statements)

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“…A square cylinder was examined experimentally (Igarashi 1984;Shao et al 2007). A square cylinder with grooves and tabs was examined (Koide et al 2006;Layukallo and Nakamura 2003;Yamagishi et al 2004). A square cylinder with rectangular cutouts at its edges was examined experimentally (Kurata and Morishita 1998).…”

Section: Introductionmentioning

confidence: 99%

Flow characteristics around a square cylinder with changing chamfer dimensions

Yamagishi

Oki

2010

J Vis

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It is known that for a square cylinder subjected to uniform flow, the drag force changes with the angle of attack. To clarify the flow characteristics around a square cylinder with corner cutoffs, we measured the drag coefficient and the Strouhal number for changing chamfer dimensions. We analyzed the flow around a square cylinder with corner cutoffs by applying the RNG k-e turbulent model, and investigated the surface flow pattern using visualization by means of the oil film and mist flow method. From these results, we obtained the surface flow patterns by the oil film method and numerical analysis. The numerical results agreed well with the experimental values. The drag coefficient of the square cylinder with corner cutoffs decreased suddenly at an angle of attack of about a = 0°-10°when compared with the drag coefficient for a square cylinder. The minimum value of the drag coefficient for the square cylinder with corner cutoffs decreased by about 30% compared with that for the square cylinder. The drag coefficient of the square cylinder with 10% corner cutoffs was found to be smallest, since the wake area of this square cylinder was smaller compared with that of the other square cylinder.

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Section: Introductionmentioning

confidence: 99%

Flow characteristics around a square cylinder with changing chamfer dimensions

Yamagishi

Oki

2010

J Vis

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“…The passive control method changed the shape of the bluff body or added other microstructures. The passive control method is simpler and less expensive ( Koide et al, 2006 ; Kim and Kim, 2012 ; Bahrami and Hacışevki, 2019 ).…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation and Deep Neural Network Revealed Drag Reduction of Microstructured Three-Dimensional Square Cylinders at High Reynolds Numbers

Wang

2022

Front. Bioeng. Biotechnol.

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Square cylinders are widely used in various fields. For example, they are common structures in fishways. The flow around square cylinders has been a common problem in various fields. However, reducing the flow drag of the square cylinder is a problem that remains unexplored. Many previous studies have reported the drag reduction of 2D square cylinders, which failed to reflect the drag of real structures. Also, some studies focus on the drag force of the inner wall of the square cylinder modified by the microstructure. Achieving drag reduction by microstructuring the surface of the 3D square cylinder is a challenging problem. This study applied a 3D numerical simulation and deep neural network to study the drag reduction performance of the square cylinder under different patch sizes. We studied the drag reduction performance of protrusion and pit-patched square cylinders and tried to find the rule between drag reduction performance and patch configuration. The results show that the square cylinder has better drag reduction performance in some cases. However, its drag reduction performance is greatly affected by the protrusion structure. Also, too large protrusions will increase the drag force of the structure. When the surface protrusion accounts for 10% of the total area of the square cylinder, the drag reduction performance is the best (22.1%). The pit patch structure demonstrated an insignificant drag reduction performance and even increased the drag in most cases. The DNN prediction model demonstrated the robustness of the numerical simulation data.

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“…Extensive research has been devoted in the past years to investigate the drag coefficient of various objects (Jones et al 1969; Koide et al 2006;Kumar and Subramanian 2007;Terry and Barber 2007;Tutar and Holdo 2001). Rahman et al (2007), investigated the flow characteristics around the circular cylinder with special attention to the mean value of the pressure drag for Re = 100, 1,000, 3,900.…”

Section: Introductionmentioning

confidence: 99%

Drag performance of divergent tubular-truncated cones: a shape optimization study

Lotfi

Rad

2011

Int. J. Environ. Sci. Technol.

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The use of more efficient energy consuming devices, which are closely associated with reduction of environmental pollution, has gained significant interest in the recent decades. The reduction of drag coefficient also improves safety and durability of environmental structures subjected to high-velocity fluid flow, and causes the noise and vibration to decrease as well. This paper describes the efficiency improvement in energy management by means of reducing drag coefficient in a practical divergent tubular-truncated cone. Extensive numerical simulations with emphasis on the shape optimization study were performed in order to find minimum drag coefficient for both laminar and turbulent flows (9.41 9 10 2 B Re B 1.882 9 10 7 ) around the mentioned cone. The numerical results were validated with experimental data, obtained by performing tests in an open circuit wind tunnel. The results showed that the minimum drag coefficient of optimum model within the shape modification process, comparable to the value for the primary model in turbulent flow decreased by 69.8% (the maximum discrepancy) at the highest considered Reynolds number of 1.882 9 10 7 . Furthermore, the study of streamwise velocity profile led to more useful result. In this regard, the velocity magnitude inside the inlet span of the primary model, close to the entrance was approximately 1.6 times as great as the free upstream velocity. This is a noticeable result for the use of efficiency important structures in industrial applications.

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Drag reduction effect of square cylinders by grooves and corner-cuttings

Cited by 3 publications

References 0 publications

Flow characteristics around a square cylinder with changing chamfer dimensions

Flow characteristics around a square cylinder with changing chamfer dimensions

Numerical Simulation and Deep Neural Network Revealed Drag Reduction of Microstructured Three-Dimensional Square Cylinders at High Reynolds Numbers

Drag performance of divergent tubular-truncated cones: a shape optimization study

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