An experimental investigation on the interaction of hydraulic jumps formed by two normal impinging circular liquid jets

2007 ◽  
Vol 590 ◽  
pp. 355-380 ◽  
Author(s):  
R. P. KATE ◽  
P. K. DAS ◽  
SUMAN CHAKRABORTY
Keyword(s):  
Experimental Investigation ◽  
Flow Field ◽  
Compressible Fluid ◽  
Hydraulic Jump ◽  
Liquid Jets ◽  
Liquid Jet ◽  
Hydraulic Jumps ◽  
Fluid Jets ◽  
The Individual ◽  
Two Jets

The flow field due to two normal impinging liquid jets is different from the flow field associated with a single normal impinging liquid jet, and even from the flow field around two normal impinging compressible fluid jets. Depending on the spacing between the two jets and their relative strengths, different kinds of hydraulic jump interactions are possible, resulting in a variety of flow patterns. The present study experimentally elucidates the jump--jump interactions formed in such cases, for different values of inter-jet spacings and for different strengths of the individual jets. Analogous flow fields associated with the interactions between a single impinging jet and a fence are also studied to allow convenient experimental flow vizualizations.

scholarly journals IDDES Evaluation of Oscillating Hydraulic Jumps

2018 ◽  
Vol 40 ◽  
pp. 05067 ◽  
Author(s):  
Vimaldoss Jesudhas ◽  
Frédéric Murzyn ◽  
Ram Balachandar
Keyword(s):  
Flow Field ◽  
Hydraulic Jump ◽  
Three Dimensional ◽  
Wall Jet ◽  
Hydraulic Jumps ◽  
Vortical Structures ◽  
Instantaneous Flow Field ◽  
Type Flow ◽  
Different Types ◽  
Flow Features

This paper presents the results of three-dimensional, unsteady, Improved Delayed Detached Eddy Simulations of an oscillating and a stable hydraulic jump at Froude numbers of 3.8 and 8.5, respectively. The different types of oscillations characterised in a hydraulic jump are analysed by evaluating the instantaneous flow field. The instability caused by the flapping wall-jet type flow in an oscillating jump is distinct compared to the jump-toe fluctuations caused by the spanwise vortices in the shear layer of a stable jump. These flow features are accurately captured by the simulations and are presented with pertinent discussions. The near-bed vortical structures in an oscillating jump is extracted and analysed using the λ2 criterion.

Experiments on the Injection of Elliptical Liquid Jets Into a Low Speed Airflow

2018 ◽  
Author(s):  
Yosef Rezaei ◽  
Mehran Tadjfar
Keyword(s):  
Experimental Investigation ◽  
Weber Number ◽  
Momentum Flux ◽  
High Speed ◽  
Flux Ratio ◽  
Major Axis ◽  
Liquid Jets ◽  
Liquid Jet ◽  
High Speed Camera ◽  
Subsonic Crossflow

An experimental investigation was performed to study the physics of liquid jets injected into a low subsonic crossflow. The jets are issued from elliptical and circular injectors with equivalent exit area. The liquid jet was visualized using shadowgraph technique and a high speed camera was used to record the instantaneous status of the jet. The liquid / air momentum flux ratio and air Weber number were varied to examine their effects on different parameters of the flow like liquid jet column trajectory, breakup point and breakup regimes. The major axis of the elliptical nozzle was aligned parallel and perpendicular to the air crossflow direction. Two different breakup modes were observed, column breakup and bag breakup. Based on the obtained results some characteristics of injected liquid jets into the air crossflow such as penetration depth and the trajectory of liquid jet were affected by changing the nozzle exit shape.

A Numerical Study on Flow Characteristics of 2D Vertical Liquid Jet Striking a Horizontal Surface

2010 ◽  
Author(s):  
M. Kimiaghalam ◽  
M. Passandideh-Fard
Keyword(s):  
Reynolds Number ◽  
Hydraulic Jump ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Newtonian Liquid ◽  
Liquid Jets ◽  
Liquid Jet ◽  
Moderate Reynolds Number ◽  
Different Types ◽  
Newtonian Liquids

We studied numerically impingement of vertical liquid jets of moderate Reynolds number for both Newtonian and non-Newtonian liquids to clarify the structure formation of circular hydraulic jump and the phenomenon of jet buckling. First, we have studied the hydraulic jump characteristics and governing parameters for a laminar water jet. Moreover, different types of hydraulic jump have been investigated by varying the height of a circular wall around the bed in flow downstream. The results show that a circular hydraulic jump has two kinds of steady states which can be reached by changing wall height. Next, we studied the impingement of a non-Newtonian liquid jet on a solid surface. In this case, we observe that instead of having a significant hydraulic jump, jet buckling phenomenon happens. The results were used in order to achieve a better understanding of the jet buckling phenomenon and the conditions in which this phenomenon happens.

Effects of Jet Obliquity on Hydraulic Jumps Formed by Impinging Circular Liquid Jets on a Moving Horizontal Plate

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
R. P. Kate ◽  
P. K. Das ◽  
Suman Chakraborty
Keyword(s):  
Hydraulic Jump ◽  
Impinging Jet ◽  
Impinging Jets ◽  
Free Surface Flows ◽  
Liquid Jets ◽  
Hydraulic Jumps ◽  
Flat Plates ◽  
Target Plate ◽  
Special Cases ◽  
Inclination Angles

The present work attempts to investigate the effects of jet obliquity on the spatial patterns formed as a consequence of hydraulic jumps due to the impingement of circular liquid jets on continuously moving but nonaccelerating horizontal flat plates. Both the normal and the oblique impinging jets are considered, in order to characterize the contrasting features of the associated hydraulic jump mechanisms. Theoretical calculations are executed to obtain the locations of the jump, for different jet and plate velocities and jet inclination angles, using a depth-averaged momentum integral equation for shallow-free surface flows. Comparisons are subsequently made between the theoretical predictions and experimental observations reported in the literature, and a good agreement between these two can be observed. Special cases of a circular hydraulic jump when the target plate is stationary and the impinging jet is vertical, and elliptic hydraulic jumps when the target plate is stationary and the impinging jet is obliquely inclined, are also discussed. It is conjectured that flow due to impinging jets on a horizontal moving plate can be modeled as an equivalent flow due to an inclined impinging jet on stationary horizontal flat plates, with appropriate alterations in the jet velocity and the jet inclination angles.

Effects of Turbulence on the Breakup of Round Liquid Jets in Gaseous Crossflow

2005 ◽  
Author(s):  
R. Sankarakrishnan ◽  
K. A. Sallam ◽  
F. W. Chambers
Keyword(s):  
Experimental Investigation ◽  
Wind Tunnel ◽  
Test Section ◽  
Drop Size ◽  
Liquid Surface ◽  
Liquid Jets ◽  
Liquid Jet ◽  
Surface Conditions ◽  
Subsonic Wind Tunnel ◽  
Primary Breakup

An experimental investigation of the effects of turbulence on primary breakup of round liquid jets subjected to gaseous crossflow is described. The paper investigates the effects of partial degrees of turbulence development in the liquid. Measurements of the properties of primary breakup were obtained using double-pulsed shadowgraphy in a subsonic wind tunnel having a test section of 0.3 m × 0.3 m × 0.6 m. Measurements included primary breakup regimes, conditions required for the onset of breakup, ligament properties along the liquid surface, drop size and velocity distributions after breakup along the liquid surface, conditions required for breakup of the liquid jet as a whole, and liquid jet trajectories.

ATOMIZATION CHARACTERISTICS OF LIQUID JETS INJECTED INTO A HIGH-VELOCITY FLOW FIELD

1994 ◽  
Vol 4 (4) ◽  
pp. 451-471 ◽  
Author(s):  
Nobuyuki Yatsuyanagi ◽  
Hiroshi Sakamoto ◽  
Kazuo Sato
Keyword(s):  
Flow Field ◽  
High Velocity ◽  
Liquid Jets ◽  
High Velocity Flow ◽  
Velocity Flow ◽  
Atomization Characteristics

Simulation of Laminar Liquid Jets in Gaseous Crossflow Before the Onset of Primary Breakup

2011 ◽  
Author(s):  
C.-L. Ng ◽  
K. A. Sallam
Keyword(s):  
Experimental Data ◽  
Fuel Injection ◽  
Liquid Jets ◽  
Liquid Jet ◽  
Jet Breakup ◽  
Primary Breakup ◽  
Density Ratios ◽  
First Time ◽  
Two Sides ◽  
Reduced Pressures

The deformation of laminar liquid jets in gaseous crossflow before the onset of primary breakup is studied motivated by its application to fuel injection in jet afterburners and agricultural sprays, among others. Three crossflow Weber numbers that represent three different liquid jet breakup regimes; column, bag, and shear breakup regimes, were studied at large liquid/gas density ratios and small Ohnesorge numbers. In each case the liquid jet was simulated from the jet exit and ended before the location where the experimental data indicated the onset of breakup. The results show that in column and bag breakup, the reduced pressures along the sides of the jet cause the liquid to move to the sides of the jet and enhance the jet deformation. In shear breakup, the flattened upwind surface pushes the liquid towards the two sides of the jet and causing the gaseous crossflow to separate near the edges of the liquid jet thus preventing further deformation before the onset of breakup. It was also found out that in shear breakup regime, the liquid phase velocity inside the liquid jet was large enough to cause onset of ligament formation along the jet side, which was not the case in the column and bag breakup regimes. In bag breakup, downwind surface waves were observed to grow along the sides of the liquid jet triggered a complimentary experimental study that confirmed the existence of those waves for the first time.

Sign in / Sign up

Export Citation Format

Share Document