Plane Turbulent Impinging Jets

Beltaos, Spyros; Rajaratnam, N.

doi:10.1080/00221687309499789

Cited by 174 publications

(118 citation statements)

References 4 publications

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“…The characteristics of two-dimensional jets passing through tailwater and impinging on a smooth rigid boundary have been investigated by Beltaos and Rajaratnam (1973) with results quite similar to those of Albertson et al (1950). The established flow region of the jet is defined as:…”

Section: Jet Diffusionsupporting

confidence: 64%

“…Values of C d suggested by Albertson et al (1950), Beltaos andRajaratnam (1973), andYuen (1984) range from 2.0 to 2.4 for well-formed jets and depend on inlet conditions. The diffused jet velocity in the scour hole U b and the diffused jet thickness Y b after the jet impinges on a boundary can be closely approximated by:…”

Section: Jet Diffusionmentioning

confidence: 99%

“…The maximum downstream face slope angle a of the scour hole occurs near the point of maximum shear stress predicted by Beltaos and Rajaratnam (1973).…”

Section: Jet Diffusionmentioning

confidence: 99%

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Scour Downstream of Grade‐Control Structures

1991

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Section: Jet Diffusionsupporting

confidence: 64%

Section: Jet Diffusionmentioning

confidence: 99%

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Scour Downstream of Grade‐Control Structures

1991

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“…As evident in the figure, our flow field is composed of three distinct regions namely exiting the jet ( § § 3.2, 4.1), realizing an asymptotic state ( § 4.2) and impinging on the plate ( § § 3.3, 4.3), and we shall consider each separately. (Beltaos & Rajaratnam 1973;Gutmark et al 1978) argue that Y 0 /h 1 and thus ignore Y 0 . They then set Y r = 1; but since the jet takes time to relax to its asymptotic state, we prefer Y r = h/2.…”

Section: Mean Flow Characteristicsmentioning

confidence: 99%

On the vortical structure in a plane impinging jet

2001

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The vortical structure of a plane impinging jet is considered. The jet was locked both in phase and laterally in space, and time series digital particle image velocimetry measurements were made both of the jet exiting the nozzle and as it impinged on a perpendicular wall. Iso-vorticity and iso-λ 2 surfaces coupled with critical point theory were used to identify and clarify structure. The flow near the nozzle was much as observed in mixing layers, where the shear layer evolves into spanwise rollers, only here the rollers occurred symmetrically about the jet midplane. Accordingly the rollers were seen to depict spanwise perturbations with the wavelength of flutes at the nozzle edge and were connected, on the same side of the jet, with streamwise 'successive ribs' of the same wavelength. This wavelength was 0.71 of the distance between rollers and, contrary to some experiments in mixing layers, did not double when the rollers paired. Structures not reported previously but evident here with iso-vorticity, λ 2 and critical point theory are 'cross ribs', which extend from the downstream side of each roller to its counterpart across the symmetry plane; their spanwise periodic spacing exceeds that of successive ribs by a factor of three. Cross ribs stretch because of the diverging flow as the rollers approach the wall and move apart, causing the vorticity within them to intensify. This process continues until the cross ribs reach the wall and merge with 'wall ribs'. Wall ribs remain near the wall throughout the cycle and are composed of vorticity of the same sign as the cross ribs, but the intensity level of the vorticity within them is cyclic. Details of the expansion of fluid elements, evaluated from the rate of strain tensor, revealed that both cross and successive ribs align with the principal axis and that the vorticity comprising them is continuously amplified by stretching. It is further shown, by appeal to the production terms of the phase-averaged vorticity equation, that wall ribs are sustained by merging and stretching rather than reorientation of vorticity. Moreover production of vorticity is a maximum when cross and wall ribs merge and is greatest near the symmetry plane of the jet. The demise of successive ribs on the other hand occurs away from the symmetry plane and would appear to be less important dynamically than cross ribs merging with wall ribs.

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“…The research of Beltaos et al [14] indicates that the round turbulent jet impact region radius is r≈0.22H, and by integrating Fr within the jet impact region it can be conducted that: 4 …”

Section: High-pressure Water Jet Cutting Radiusmentioning

confidence: 99%

Drainage Radius after High Pressure Water Jet Slotting Based on Methane Flow Field

Xia¹,

Zhao²,

Lu³

et al. 2016

IJHT

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Considering that the methane drainage radius cannot speedily and accurately be confirmed after high pressure water jet slotting, a model for slotting the radius of high pressure water jet slotting is established based on the theory of round turbulent jet and Loland damage model. Combining the linear seepage theory and nonlinear seepage theory, this paper proposes the seepage model for various seepage statuses around the slot. The methane drainage radius after using a high pressure water jet consists of three parts: slotting radius, linear seepage area and nonlinear seepage area. Taking Zhongliangshan Mine as an example, the calculated results show that the slotting radius is 1.57m. The linear seepage areas range from 1.57m to 4.81m, and the nonlinear seepage areas range from 4.81m to 9.36m from the center of borehole, respectively. Field experimentation shows that the radius of slotting reaches 1.5m. The effective drainage radius is 5m and the radius of influence is 9m. It is relatively consistent with the theoretical calculations.

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Plane Turbulent Impinging Jets

Cited by 174 publications

References 4 publications

Scour Downstream of Grade‐Control Structures

Scour Downstream of Grade‐Control Structures

On the vortical structure in a plane impinging jet

Drainage Radius after High Pressure Water Jet Slotting Based on Methane Flow Field

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