Turbulent Boundary Layers with Injection and Suction through a Slit : 1st Report, Mean and Turbulence Characteristics

Sano, Masatoshi; Hirayama, Naomichi

doi:10.1299/jsme1958.28.807

Cited by 39 publications

(5 citation statements)

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“…Obviously, the value and area of the former are larger than those of the latter. This is consistent with the conclusion obtained by Sane and Hirayama [30] that for the same mass flux, the average influence of blowing on the flow field is greater than that of suction. Strong shear can be seen from the dense contour lines between the middle and both sides, resulting in the generation of vortex structure.…”

Section: Phase Average Of Flow Fieldsupporting

confidence: 93%

Effects of single synthetic jet on turbulent boundary layer

Zhang

Wang

et al. 2022

Chinese Phys. B

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The turbulent boundary layer (TBL) was actively controlled by the synthetic jet generated from a circular hole. According to datasets of velocity fields acquired by a time-resolved particle image velocimetry (TR-PIV) system, the average drag reduction rate of 6.2% was obtained downstream of the hole with control. The results of phase averaging show that the synthetic jet generates one vortex pair each period and the consequent vortex evolves into hairpin vortex in the environment with free-stream, while the reverse vortex decays rapidly. By statistical average, it can be found that a low-speed streak is generated downstream. Induced by the two vortex legs, the fluid under them converges to the middle. The drag reduction effect produced by the synthetic jet is local, and it reaches the maximum at x + = 400, where the drag reduction rate reaches about 12.2%. After extraction of coherent structure by the spatial two-point correlation analysis, it can be seen that the synthetic jet suppresses the streamwise scale and wall-normal scale of the large-scale coherent structure, and slightly weakens the spanwise motion to achieve the effect of drag reduction.

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Section: Phase Average Of Flow Fieldsupporting

confidence: 93%

Effects of single synthetic jet on turbulent boundary layer

Zhang

Wang

et al. 2022

Chinese Phys. B

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“…[1][2][3][4][5][6][7][8] It has been known that in a turbulent boundary layer uniform blowing from the wall decreases the skin friction and increases the strength of fluctuating quantities, while uniform suction has nearly the opposite effect. However, the increase of turbulent fluctuations from blowing may cause an increase of drag in the downstream due to strong turbulent motion there.…”

Section: Introductionmentioning

confidence: 99%

Effects of uniform blowing or suction from a spanwise slot on a turbulent boundary layer flow

Park¹,

Choi²

1999

Physics of Fluids

144

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Effects of uniform blowing or suction from a spanwise slot on a turbulent boundary layer flow are investigated using the direct numerical simulation technique. The magnitudes of blowing or suction are less than 10% of the free-stream velocity. The skin friction and near-wall turbulence intensities are significantly changed by blowing and suction. In the case of uniform blowing, the skin friction on the slot rapidly decreases. The streamwise vortices above the wall are lifted up by blowing, and thus the interaction of the vortices with the wall becomes weaker. Accordingly, the lifted vortices become stronger in the downstream due to less viscous diffusion (above the slot) and more tilting and stretching (downstream of the slot), resulting in the increase of the turbulence intensities as well as the skin friction downstream of the slot. The opposite is observed in the case of uniform suction. The velocity fluctuations and Reynolds shear stress react quickly to blowing but recover slowly in the downstream, as compared to the case of suction. For both cases of blowing and suction, the streamwise turbulence intensity recovers quickly from blowing or suction, while other components of the turbulence intensities and Reynolds shear stress recover in a longer downstream distance.

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“…Sano and Hirayama (1985); Antonia et al (1988Antonia et al ( , 1995; Oyewola et al (2001); Pailhas et al (1991); Merigaud et al, (1996)]. The interesting result that emerged is that suction could be used for controlling the flow, in particular for delaying transition and separation (Gad-el-Hak, 1989, 1998.…”

Section: Introductionmentioning

confidence: 99%