scholarly journals Air concentration distribution in deflector-jets

2014 ◽  
Author(s):  
M. Pfister ◽  
S. Schwindt
Keyword(s):  
Concentration Distribution ◽  
Air Concentration

scholarly journals Experimental Study on the Air Concentration Distribution of Aerated Jet Flows in a Plunge Pool

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1779 ◽  
Author(s):  
Weilin Xu ◽  
Chunqi Chen ◽  
Wangru Wei
Keyword(s):  
Concentration Distribution ◽  
Discharge Rate ◽  
Lateral Diffusion ◽  
Jet Flows ◽  
Analysis Model ◽  
Air Concentration ◽  
Initial Flow ◽  
Plunge Pool ◽  
Physical Experiments ◽  
Air Diffusion

There is a lack of knowledge on the air concentration distribution in plunge pools affected by aerated jets. A set of physical experiments was performed on vertical submerged aerated jet flows impinging a plunge pool. The air concentration distribution in the plunge pool was analyzed under different inflow air concentrations, flow velocities, and discharge rate conditions. The experimental results show that the air concentration distribution follows a power-law along the jet axis, and it is independent of the initial flow conditions. A new hypothetical analysis model was proposed for air diffusion in the plunge pool, that is, the air concentration distribution in the plunge pool is superposed by the lateral diffusion of three stages of the aerated jet motion. A set of formulas was proposed to predict the air concentration distribution in the plunge pool, the results of which showed good agreement with the experimental data.

scholarly journals Mathematical simulation of air-water flow along Ski Jump Jet

2021 ◽  
Author(s):  
Roghayeh Ahmadpour ◽  
Hamed Sarkardeh ◽  
Hazi Azamathulla
Keyword(s):  
Numerical Simulation ◽  
Water Flow ◽  
Concentration Distribution ◽  
Analytical Data ◽  
Geometrical Parameters ◽  
Flow Depth ◽  
Air Concentration ◽  
Black Water ◽  
Core Length ◽  
Analytical Simulation

Abstract In the present study, using a quasi 3D analytical simulation, air concentration distribution in ski jump generated jet is calculated. A numerical simulation is also performed to verify the results of the analytical model in parallel with the available experimental and another analytical data. By solving continuity and momentum equations in case of air-water flow for three different cases, it was confirmed that the air concentrations along the ski jet are uniquely linked to the relative black water core length. Results showed that the black water core length is also influenced by the approach flow depth, Froude number, geometrical parameters of ski jump and the chute bottom angle. Finally, an analytical equation is proposed to predict the air concentration distribution along the ski jump jet regarding different hydraulic and geometric parameters. By calculating the velocity profiles along the jet, it showed that increasing the air concentration reduces the jet velocity profile.

scholarly journals MODIFICATION EQUATIONS OF AIR BUBBLES DISTRIBUTIONS AT SELF-AIR ENTRAINMENT CONDITION

2020 ◽  
Vol 82 (2) ◽  
Author(s):  
Yeri Sutopo ◽  
Budi S. Wignyosukarto ◽  
Bambang Yulistyanto ◽  
Istiarto Istiarto ◽  
Nor Hayati Abdul Hamid
Keyword(s):  
Concentration Distribution ◽  
Vertical Direction ◽  
Air Entrainment ◽  
Experimental Results ◽  
Air Bubbles ◽  
Air Concentration ◽  
Air Bubble ◽  
Discharge Water ◽  
Flow Surface ◽  
Imagej Software

The Chanson’s equation for distribution of air bubbles in vertical direction in the developing zone at self-air entrainment condition is used when the air bubbles concentration at the flow surface is 90%. Otherwise, if this condition is not satisfying, then the equations of Straub and Anderson can be used. The results of these two equations are not similar with experimental results. Therefore, these two equations need to be modified accordingly. These modification equations can also be used to predict the air bubbles distributions in vertical direction. Hence, the main objective of this study is to modify these equations for vertical air concentration distribution in the developing zone and validate them with experimental results. The steep channel in the form of flume with 10 m long, 0.2 m wide and 0.4 m high with slopes varies between 20° and 25° were used in this experimental work. The discharge water was 9 l/s, 12 l/s and 21 l/s with Froude numbers between 6.9 to 8.0. The Thomson weir (V Notch) was used to calibrate the discharge flow of water. A set of video cameras was used to record the motion pictures of the air bubbles. The air bubble was analyzed using Ulead Video Studio 11 software program equipped with Imagej software. The results of this study indicates that the modifications of equations of Straub and Anderson were the equation air concentration distribution (C) in the underlying zone value was 0.647 m at 20° slope of channel bed, the equation air concentration distribution (C) in the underlying zone the value was 0.542 m at 25° slope and the equation in the mixing zone remained the same. The original Chanson equation was modified mainly in terms of the hyperbolic tangent (tanh) equation which originally had a power of 2 while the modification was 0.8; and the Ce was 0.9 sin α, whereas at the modified Chanson’s equation, Ce was converted into Ce= 0.6 sin α.

AIR CONCENTRATION DISTRIBUTION DOWNSTREAM OF SPILLWAY AERATORS

1996 ◽  
Vol 2 (1) ◽  
pp. 33-46
Author(s):  
N. R. Afshar ◽  
G. L. Asawa ◽  
K. G. Ranga Raju
Keyword(s):  
Concentration Distribution ◽  
Air Concentration

Air concentration distribution in self-aerated flow

1994 ◽  
Vol 32 (4) ◽  
pp. 623-631 ◽  
Author(s):  
N. R. Afshar ◽  
G. L. Asawa ◽  
K. G. Ranga Raju
Keyword(s):  
Concentration Distribution ◽  
Air Concentration ◽  
Aerated Flow

scholarly journals Performance and Design of a Stepped Spillway Aerator

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 153
Author(s):  
Stéphane Terrier ◽  
Michael Pfister ◽  
Anton J. Schleiss
Keyword(s):  
Concentration Distribution ◽  
Water Discharge ◽  
Air Entrainment ◽  
Stepped Spillway ◽  
Flow Depth ◽  
Air Concentration ◽  
Stepped Spillways ◽  
Jet Impact ◽  
Entrainment Coefficient ◽  
Pressure Water

Stepped spillways are frequently limited to specific discharges under around 30 m2/s due to concerns about potential cavitation damages. A small air concentration can prevent such damages and the design of bottom aerators is well established for smooth chutes. The purpose of this study is to systematically investigate the performance of a deflector aerator at the beginning of stepped chutes. Six parameters (chute angle, step height, approach flow depth, approach flow Froude number, deflector angle and deflector height) are varied in a physical model. The spatial air concentration distribution downstream of the aerator, the cavity sub-pressure, water discharge and air discharges are measured. The results describe the commonly used air entrainment coefficient, the jet length, as well as the average and bottom air concentration development to design an aerator. The lowest bottom air concentration measured in all tests is higher than the air concentration recommended in literature to protect against cavitation damages. And, unlike smooth chutes, there appears to be no significant air detrainment downstream of the jet impact. One deflector aerator seems therefore sufficient to provide protection of a stepped spillway.

Sign in / Sign up

Export Citation Format

Share Document