scholarly journals Near-field dynamics of parallel twin jets in cross-flow

2017 ◽  
Vol 29 (3) ◽  
pp. 035103 ◽  
Author(s):  
B. Zang ◽  
T. H. New
Keyword(s):  
Near Field ◽  
Cross Flow ◽  
Twin Jets

scholarly journals 2D PIV Measurement of Twin Buoyant Jets in Wavy Cross-Flow Environment

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 399 ◽  
Author(s):  
Zhenshan Xu ◽  
Ebenezer Otoo ◽  
Yongping Chen ◽  
Hongwei Ding
Keyword(s):  
Current Velocity ◽  
Near Field ◽  
Velocity Ratio ◽  
Cross Flow ◽  
Buoyant Jets ◽  
Flow Environment ◽  
Piv Measurement ◽  
Jet Trajectory ◽  
Twin Jets ◽  
Effluent Discharge

The multiport diffuser effluent discharge facilities constructed beneath the coastal waters were simplified in the laboratory as twin buoyant jets in a wavy cross-flow environment. The near-field flow structure of twin jets was studied by series of experiments conducted in a physical wave–current flume. The particle image velocimetry (PIV) system was used to measure the velocity field of the jets in various cross-flow-only and wavy cross-flow environments. By means of flow visualization, the distinctive “effluent cloud” (EC) phenomenon was clearly observed and the jet penetration height was found to be notably increased compared with that of cross-flow-only environment at the downstream position. It was found that the wave-to-current velocity ratio Rwc is a very important parameter for effluent discharge. A new characteristic velocity uch and the corresponding characteristic length scale lmb for twin buoyant jets in the wavy cross-flow environment were defined. Using curve-fitting, a new equation to estimate the effects of the jet-to-current velocity ratio (Rjc), wave-to-current velocity ratio (Rwc) and Strouhal number (St) on the jet trajectory were derived to enhance understanding the physical processes underpinning the rise and the dilution of buoyant jets, which is critical to the design of discharge facilities.

Twin jets in cross-flow

2011 ◽  
Vol 66 (12) ◽  
pp. 2616-2626 ◽  
Author(s):  
V.S. Naik-Nimbalkar ◽  
A.D. Suryawanshi ◽  
A.W. Patwardhan ◽  
I. Banerjee ◽  
G. Padmakumar ◽  
...  
Keyword(s):  
Cross Flow ◽  
Twin Jets

Vorticity and Circulation Aspects of Twin Jets in Cross-Flow for an Oblique Nozzle Arrangement

2006 ◽  
Vol 220 (4) ◽  
pp. 247-252 ◽  
Author(s):  
V Kolář ◽  
E Savory ◽  
H Takao ◽  
T Todoroki ◽  
S Okamoto ◽  
...  
Keyword(s):  
Cross Flow ◽  
Twin Jets

Numerical Simulation of Jet and Cross-Flow Mixing in Tee Pipe

2014 ◽  
Vol 960-961 ◽  
pp. 523-527
Author(s):  
Guo Bing Kang
Keyword(s):  
Near Field ◽  
Cross Flow ◽  
Experimental Result ◽  
Pipe Diameter ◽  
Injection Point ◽  
Mixing Effect ◽  
Inlet Velocity ◽  
Flow Mixing ◽  
Mixing Parameter ◽  
Cross Flow Velocity

In the present paper we investigated the mixing effect of uncompressible jet and cross-flow in Tee pipe based CFD, the model of Realizable was employed as the tool to simulate the flow field, and the model was validated by experimental result of relative research. The mixing effect of jet and cross-flow in various configuration of Tee pipe at different inlet velocity of jet was discussed. The result shows jet and cross-flow mix quickly in near field of injection point, but in the downstream, the mixing effect keeps comparatively steady whenz>7d, and there is power relation between the mixing parameterMandr1×r2. Andr1is the ratio of jet pipe diameter to cross-flow pipe diameter,r2is the ratio of jet velocity to cross-flow velocity.

Experimental study on impingement spray and near-field spray characteristics under high-pressure cross-flow conditions

Fuel ◽  
2018 ◽  
Vol 218 ◽  
pp. 12-22 ◽  
Author(s):  
Zhanbo Si ◽  
Nagisa Shimasaki ◽  
Keiya Nishida ◽  
Youichi Ogata ◽  
Min Guo ◽  
...  
Keyword(s):  
Experimental Study ◽  
High Pressure ◽  
Near Field ◽  
Cross Flow ◽  
Flow Conditions ◽  
Spray Characteristics

Dynamics of Large-Scale Structures for Jets in a Crossflow

1998 ◽  
Author(s):  
Frank Muldoon ◽  
Sumanta Acharya
Keyword(s):  
Shear Layer ◽  
Large Scale ◽  
Computational Study ◽  
Near Field ◽  
Velocity Ratio ◽  
Cross Flow ◽  
Leeward Side ◽  
Mean Velocity ◽  
Large Scale Structures ◽  
Scale Structures

Results of a three dimensional unsteady computational study of a row of jets injected normal to a cross-flow are presented with the aim of understanding the dynamics of the large scale structures in the region near the jet. The jet to cross-flow velocity ratio is .5. A modified version of the computer program (INS3D) which utilizes the method of artificial compressibility is used for the computations. Results obtained clearly indicate that the near field large scale structures are extremely dynamical in nature, and undergo breakup and reconnection processes. The dynamical near field structures identified include the counter rotating vortex pair (CVP), the horseshoe vortex, wake vortex, wall vortex and the shear layer vortex. The dynamical features of these vortices are presented in this paper. The CVP is observed to be a convoluted structure interacting with the wall and horseshoe vortices. The shear layer vortices are stripped by the crossflow, and undergo pairing and stretching events in the leeward side of the jet. The wall vortex is reoriented into the upright wake system. Comparison of the predictions with mean velocity measurements is made. Reasonable agreement is observed.

Experimental Investigation of Droplet Velocity Fields From Elliptic Injectors in Subsonic Cross Flow

2019 ◽  
Author(s):  
Ather Uzair Alvi ◽  
Amit Thakur ◽  
Srinivas Jangam ◽  
Pratheesh Kumar P. ◽  
Venkat S. Iyengar
Keyword(s):  
Velocity Field ◽  
Gas Turbine ◽  
Test Section ◽  
Environmental Control ◽  
Near Field ◽  
Cross Flow ◽  
Flame Stabilization ◽  
Droplet Velocity ◽  
Lateral Spread ◽  
Liquid Jet

Abstract The flow field associated with a liquid jet injected transversely into a crossflow, also referred as transverse jet has numerous applications in industrial, environmental and natural systems. Examples of these applications include air-breathing engines (gas turbine afterburners, ramjet and scramjet combustors), rocket engines, environmental control systems and natural flows. Earliest research of a jet in a crossflow has been motivated by applications related to environmental problems such as plume dispersal from exhaust or pipe stacks or liquid effluent dispersal in streams. This method of liquid fuel/air mixture preparation enhances flame stabilization, fuel conversion efficiency, and reduction in emissions. In gas turbine applications because of the very limited residence time available for effective fuel air mixing, detailed investigations into spray characteristics of different injector configurations in a crossflow environment is desirable for identifying promising configurations with measurements in the near field to acquire reliable spray data for development of CFD models. The velocity field of a liquid jet in the near field ejecting out from an elliptic injector into a crossflow of air were investigated experimentally at conditions relevant to gas turbine applications. A rig was set up to investigate the injection of liquid jet in subsonic cross flow with a rectangular test section of cross section measuring 100 mm by 140 mm. Experiments were done with a two injector configurations a circular 0.8mm diameter plain orifice injector and a elliptic injector with an equivalent effective area of 0.7 mm (minor axis) by 0.95 mm (major axis) which was flush mounted on the bottom plate of test section. PIV technique was used to measure droplet velocity field and distributions in the near field of the spray. Measurements were performed at a distance of 5 mm from the bottom wall in the span wise plane and the results were compared with a circular injector. It was seen that no significant differences were observed in the u and v velocity components for the elliptic and circular injectors where the geometry changes are small suggesting that parameters like velocity are not significantly affected by small changes in injector exit geometry. Further for elliptic jets it was observed that increasing the crossflow velocity and maintaining the same liquid flow rate lead to an increase in the lateral spread of the spray with no significant change in the mean vorticity values.

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