Turbulent Drag Reduction Characteristics of Bionic Nonsmooth Surfaces with Jets

Song, Xiaowen; Zhang, Ming-xiao

doi:10.3390/app9235070

Cited by 7 publications

(4 citation statements)

References 44 publications

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“…In order to save the research cost and speed up the research, most scholars currently use numerical simulation to study the flow field of the transverse jet: Qiu used the k-ε standard model for numerical simulation of flowing residence characteristics of the transverse jet [19]; Song and Zhang conducted numerical simulation research on turbulent drag reduction characteristics of transverse jets, using the turbulence model SST k-ω [20]; Demena used the RSM turbulence model to analyze the flow field of the transverse jet in crossflow [21]. However, from the open literature, there is no report on the selection of a suitable turbulence model used for the numerical simulation of the transverse jet, and no unified conclusion has been formed.…”

Section: Turbulence Model Selection and Analysismentioning

confidence: 99%

The Recirculation Zone Characteristics of the Circular Transverse Jet in Crossflow

Yuan

Guo

et al. 2020

Energies

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Transverse jets in crossflow are widely used in energy systems, especially as dilution air jets, fuel/air mixers, and combustion equipment, and have received extensive attention and plenty of research. However, the studies of the circular transverse jet issued from a circular gap at the circumferential direction of a tube in crossflow are very limited. This paper studies a relatively new jet: the circular transverse jet. Firstly, numerical calculations are conducted under different turbulence models but with the same boundary conditions. By comparing the numerical results of different turbulence models with the existing experimental data, the turbulence model which is most suitable for the numerical calculation of the circular transverse jet is selected. Then, this turbulence model is used to calculate and analyze the flow field structure and its characteristics. It is found that due to the aerodynamic barrier effect of the high-velocity jet, a negative pressure zone is formed behind the jet trajectory; the existence of the negative pressure zone causes the formation of a vortex structure and a recirculation zone downstream the circular transverse jet; and the length/width ratio of the recirculation zone does not change with the changes of the crossflow and the jet parameters. It means that the recirculation zone is a fixed shape for a definite device. This would be fundamental references for the studying of fuel/air mixing characteristics and combustion efficiency when the circular transverse jet is used as a fuel/air mixer and stable combustion system.

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Section: Turbulence Model Selection and Analysismentioning

confidence: 99%

The Recirculation Zone Characteristics of the Circular Transverse Jet in Crossflow

Yuan

Guo

et al. 2020

Energies

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“…However, it is found more common in literature the development of surface geometry that mimics shark skin allowing drag reduction with respect to a smooth surface [5][6][7]. Coherently, also surface textures capabilities are faced [8][9][10]. Drag reduction studies frequently refer to their results in terms of percentage of reduction with respect to the untreated, unaffected, smooth or reference condition.…”

Section: Introductionmentioning

confidence: 99%

Feasibility of using bio-mimicking fish scale textures in LPBF for water drag-reducing surfaces

2023

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In this work, bio-mimicking fish scale textures are produced by LPBF and AlSi7Mg0.6 powder to reduce drag forces on nautical components. For this purpose, a surface texture inspired by the European bass skin was modelled and parametrized. Textures were applied over the external surface of purpose-designed specimens. Additive manufacturing quality of textures was assessed using focus variation microscopy to examine surface roughness as well as geometrical errors. Once the feasibility of producing the desired bio-mimicking surfaces was confirmed, the designed surface patterns were analysed in the computation fluid dynamics modelling environment. The behaviour of the surfaces was characterized in terms of drag force generated over a fixed dimension plate model. The most promising configuration was further investigated in a sensitivity analysis where variations in main stream velocity and in surface roughness are applied. Drag reduction was related to the lowering of the viscous component and was found to be in the order of 1–2%, with respect to a smooth surface, for free stream velocity of 2.5–5 m s−1 and average roughness smaller than the as-built condition. The results confirm that the modelled surfaces can be reproduced with sufficient geometrical fidelity, showing great promise for drag-reducing metallic components produced by additive manufacturing.

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“…Riblet is one of the most promising drag reduction methods. Its DR rate can reach 10%, and it has attracted significant attention in scientific research and engineering applications [13][14][15][16][17][18]. Walsh [19] demonstrated the drag reduction effect of micro-riblets in the earliest experiments.…”

Section: Introductionmentioning

confidence: 99%

Controllable deformation based self‐adaptive drag reduction for complex surface

Chen

Cui

Chen

2023

Biosurface and Biotribology

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Reduction of energy consumption and improvement of cruising speed are greatly necessary for underwater vehicles. Previously, regular riblets have been machined and the drag reduction has been verified; however, the riblet parameters are not adjusted like the denticles of sharkskin, which adapt quickly to the complex changing fluid flow. To achieve an improved drag reduction effect on the complicated shape surface, a simple, low‐cost, and timesaving stretching approach was proposed to adjust the riblet parameters on the underwater vehicle surface by controllable deformation. Nature latex rubber membrane with regular micro‐riblets was prepared as a stretching flexible film, and the spacing and height of the micro‐riblets were adjusted by adaptive control of the stretching ratio. The circulating water channel experiment verified the effectiveness and feasibility of the self‐adaptive drag reduction by the controllable deformation method. The results demonstrated that the drag reduction rate of the controllable deformation bionic fish skin was 4.26% compared with a smooth surface at 0.25 m/s with an angle of attack of 0°, which is better than any other angle. The controllable deformation bionic fish skin provides a feasible method for the drag reduction of complex surface adaptive underwater vehicles.

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Turbulent Drag Reduction Characteristics of Bionic Nonsmooth Surfaces with Jets

Cited by 7 publications

References 44 publications

The Recirculation Zone Characteristics of the Circular Transverse Jet in Crossflow

The Recirculation Zone Characteristics of the Circular Transverse Jet in Crossflow

Feasibility of using bio-mimicking fish scale textures in LPBF for water drag-reducing surfaces

Controllable deformation based self‐adaptive drag reduction for complex surface

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