Non-isothermal mixing characteristics in the extreme near-field of a turbulent jet in hot crossflow

2019 ◽  
Vol 31 (12) ◽  
pp. 125104 ◽  
Author(s):  
James W. Dayton ◽  
Benjamin K. Poettgen ◽  
Kyle Linevitch ◽  
Baki M. Cetegen
Keyword(s):  
Near Field ◽  
Turbulent Jet ◽  
Mixing Characteristics ◽  
Isothermal Mixing

Near-Field Characteristics of a Turbulent Jet With Ring Injectors

2009 ◽  
Author(s):  
Hamid R. Rahai ◽  
Shahab Moayedian
Keyword(s):  
Cross Section ◽  
Near Field ◽  
Turbulent Jet ◽  
Hole Injection ◽  
Mean Velocity ◽  
Blowing Ratio ◽  
Velocity Decay ◽  
Axial Variation ◽  
Inner Diameter ◽  
Axis Switching

Mixing effectiveness of a heated turbulent jet with two-hole and three-hole ring injectors was experimentally investigated. The injectors were rings with square cross section with side dimensions of approximately 5 mm. The ratio of the ring thickness to the jet inner diameter was 4.7%. For the two-hole injector, the injecting holes were at 180 degrees from each other and for the three-hole injectors, the holes were spaced at 120 degrees. The maximum mean velocity of the jet was at approximately 4 m/s which corresponds to an approximate Reynolds number based on the jet inner diameter of 14,676. The total blowing ratio as compared to the axial momentum for each configuration was at 2%. Results indicate significant increases in RMS fluctuation and mean velocity decay with the ring injectors with these effects being more pronounced for the three-hole injection. Axial variation of momentum thicknesses indicates a possibility of axis switching in the near field for the three-hole ring injector.

Near-field dilution of a turbulent jet discharged into coastal waters: Effect of regular waves

2017 ◽  
Vol 140 ◽  
pp. 29-42 ◽  
Author(s):  
Zhenshan Xu ◽  
Yongping Chen ◽  
Yana Wang ◽  
Changkuan Zhang
Keyword(s):  
Coastal Waters ◽  
Near Field ◽  
Turbulent Jet ◽  
Regular Waves

Self-generation of organized waves in an impinging turbulent jet at low Mach number

1982 ◽  
Vol 117 ◽  
pp. 425-441 ◽  
Author(s):  
Donald Rockwell ◽  
Andreas Schachenmann
Keyword(s):  
Mach Number ◽  
Phase Difference ◽  
Acoustic Waves ◽  
Near Field ◽  
Turbulent Jet ◽  
Maximum Pressure ◽  
Pressure Amplitude ◽  
Axisymmetric Cavity ◽  
Low Mach Number ◽  
Oscillation Frequencies

Self-generation of highly organized waves in a nominally turbulent jet at very low Mach number can arise from its impingement upon the downstream orifice of an axisymmetric cavity, having an impingement length much shorter than the corresponding acoustic wavelength. The oscillation frequencies are compatible with the resonant modes of a long pipe located upstream of the cavity and with jet-instability frequencies based on the column mode (0·3 [siml ] SD [siml ] 0·6), as well as the near-field shear layer mode (0·016 [siml ] Sθ0 [siml ] 0·03). Moreover, the frequency of the organized wave is constant from separation to impingement; consequently vortex pairing does not occur.Within the cavity, the pressure amplitude associated with the organized wave is directly related to the phase difference between the organized velocity fluctuations at separation and impingement. Maximum pressure amplitude occurs when this phase difference, measured along the cavity (i.e. jet) centre-line, is 2nπ. Streamwise amplitude and phase distributions of the organized wave cannot be explained from purely hydrodynamic considerations; however, they can be effectively modelled by superposing contributions from hydrodynamic and acoustic waves. This aspect has important consequences for externally excited jets as well.

Velocity and orientation distributions of fibrous particles in the near-field of a turbulent jet

2015 ◽  
Vol 276 ◽  
pp. 10-17 ◽  
Author(s):  
Guoqiang Qi ◽  
Graham J. Nathan ◽  
Timothy C.W. Lau
Keyword(s):  
Near Field ◽  
Turbulent Jet ◽  
Orientation Distributions
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