scholarly journals Experimental Study of a Sphere Bouncing on the Water

2022 ◽  
Author(s):  
Xujian Lyu ◽  
Honglu Yun ◽  
Zhaoyu Wei
Keyword(s):  
Initial Velocity ◽  
Water Surface ◽  
High Speed ◽  
Impact Angle ◽  
Impact Dynamics ◽  
Surface Evolution ◽  
Flow Physics ◽  
Motion Characteristics ◽  
The Impact ◽  
The Relationship

Abstract In this paper, the flow physics and impact dynamics of a sphere bouncing on a water surface are studied experimentally. During the experiments, high-speed camera photography techniques are used to capture the cavity and free surface evolution when the sphere impacts and skips on the water surface. The influences of the impact velocity (v1) and impact angle (θ1) of the sphere on the bouncing flow physics are also investigated, including the cavitation evolution, motion characteristics, and bounding law. Regulations for the relationship between v1 and θ1 to judge whether the sphere can bounce on the water surface are presented and analyzed by summarizing a large amount of experimental data. In addition, the effect of θ1 on the energy loss of the sphere is also analyzed and discussed. The experiment results show that there is a fitted curve of $${v}_{1}=17.5{\theta }_{1}-45.5$$ v 1 = 17.5 θ 1 - 45.5 determining the relationship between the critical initial velocity and angle whether the sphere bounces on the water surface.

Splash formation by spherical drops

2001 ◽  
Vol 427 ◽  
pp. 73-105 ◽  
Author(s):  
LIOW JONG LENG
Keyword(s):  
High Resolution ◽  
Quantitative Data ◽  
Water Surface ◽  
High Speed ◽  
Scaling Laws ◽  
Capillary Wave ◽  
Water Drop ◽  
Qualitative And Quantitative ◽  
High Resolution Images ◽  
The Impact

The impact of a spherical water drop onto a water surface has been studied experimentally with the aid of a 35 mm drum camera giving high-resolution images that provided qualitative and quantitative data on the phenomena. Scaling laws for the time to reach maximum cavity sizes have been derived and provide a good fit to the experimental results. Transitions between the regimes for coalescence-only, the formation of a high-speed jet and bubble entrapment have been delineated. The high-speed jet was found to occur without bubble entrapment. This was caused by the rapid retraction of the trough formed by a capillary wave converging to the centre of the cavity base. The converging capillary wave has a profile similar to a Crapper wave. A plot showing the different regimes of cavity and impact drop behaviour in the Weber–Froude number-plane has been constructed for Fr and We less than 1000.

scholarly journals Experimental Study of Drop Impact on Deep-Water Surface in the Presence of Wind

2018 ◽  
Vol 48 (2) ◽  
pp. 329-341 ◽  
Author(s):  
Xinan Liu
Keyword(s):  
Deep Water ◽  
Water Surface ◽  
Water Drop ◽  
Threshold Value ◽  
Impact Angle ◽  
Drop Impact ◽  
Wind Speeds ◽  
Secondary Droplets ◽  
Low Wind Speeds ◽  
The Impact

AbstractThe effects of wind on the impact of a single water drop on a deep-water surface are studied experimentally in a wind tunnel. Experiments are performed by varying impacting drop diameters, ranging from 2.5 to 4.1 mm and wind speeds up to 6.7 m s−1. The sequence of splashing events that occurred during drop impacts is recorded with a backlit, cinematic shadowgraph technique. The experimental results show that for low wind speeds, an asymmetrical crown forms on the leeward of the periphery of the colliding region after the drop hits the water surface, while a wave swell forms on the windward. Secondary droplets are generated from the crown rim. For high wind speeds with large drop diameters, ligaments are generated from the crown rim on the leeward of the drop impact site. The ligaments grow, coalesce, and fragment into secondary droplets. It is found that both the drag force and surface tension play important roles in the evolution process of the ligaments. The nondimensional K number (K = WeOh−0.4, where We is the Webber number and Oh is the Ohnesorge number) is used to describe the splashing-deposition limit of drop impact. The threshold value of this K number changes with the wind velocity and/or drop impact angle.

Experimental Study on Splashing During Liquid Jet Impingement Onto a Liquid Film

2016 ◽  
Author(s):  
Zhan Yi ◽  
Naoki Oya ◽  
Koji Enoki ◽  
Tomio Okawa ◽  
Shuji Ohno ◽  
...  
Keyword(s):  
Liquid Film ◽  
High Speed ◽  
Nuclear Power ◽  
Jet Impingement ◽  
Liquid Jet ◽  
Jet Engine ◽  
Transition Length ◽  
The Impact ◽  
The Relationship ◽  
Fire Accident

A liquid jet is of considerable importance in many industrial fields including jet cleaning, jet engine and combustion. As an important example, the Monju nuclear power plant in Japan experienced a sodium leak in 1995. This led to a fire accident because the sodium reacted with oxygen in the air. To predict the significance of the fire accident, accurate evaluation of the amount of splashed droplets caused by the sodium jet impingement is of great importance. In this work, the relationship between the condition of a liquid jet and the amount of splashed droplets is explored experimentally. In the experiments, a liquid jet was emanated vertically downward from a circular nozzle onto a liquid film formed on a horizontal plate. Visualization using a high speed camera was performed to observe the condition of the liquid jet. From the nozzle, the mode of the liquid jet changed jet, lump and drop. Here, the jet mode means the continuous jet with smooth surface, the lump mode the continuous jet with disturbed surface and the drop mode the broken jet. Dependences of the transition length to each mode on the important parameters such as the jet velocity and the nozzle diameter were investigated. Measurement was also conducted for the splash ratio that is defined as the ratio of the amount of splashed droplets to the jet flow rate. It was found that the splash ratio is high when the liquid jet is in the drop mode at the impact point. It was shown that the splash ratio can be correlated well as a function of the impact Weber number and the Strouhal number of the droplets impinging the liquid film.

scholarly journals Impact and Ricochet of a High Speed Projectile from a Plate

2021 ◽  
Vol 71 (6) ◽  
pp. 737-747
Author(s):  
Hussein Bassindowa ◽  
Bakhtier Farouk ◽  
Steven B. Segletes
Keyword(s):  
Titanium Alloy ◽  
High Speed ◽  
Computational Study ◽  
Incident Angle ◽  
Finite Thickness ◽  
Impact Angle ◽  
Projectile Velocity ◽  
Alloy Plate ◽  
Impact Angles ◽  
The Impact

A computational study of a projectile (either 2024 aluminum or TiAl6V4 titanium alloy) impacting a plate (either titanium alloy or aluminum) is presented in this paper. Projectile velocity (ranging from 250 m/s to 1500 m/s) with varying impact angles are considered. The presence of ricochet (if any) is identified over the ranges of the projectile velocity and impact angle considered. For the cases where ricochet is identified, the ricochet angle and velocity are predicted as functions of the incident angle and the incident velocity. The numerical results are compared with an analytical solution of the ricochet problem. The analytical solutions are from a model developed to predict the ballistic ricochet of a projectile (projectile) penetrator. The dynamics and the deformation of an aluminum (or a titanium alloy) projectile impacting on a finite thickness titanium alloy (or aluminum) plate are simulated. The current work is interesting in that it looks in the field of ballistics of different material combinations than are traditionally studied. The present simulations based on detailed material models for the aluminum and the titanium alloy and the impact physics modelling features in the LS-DYNA code provide interesting details regarding the projectile/plate deformations and post-impact projectile shape and geometry. The present results indicate that for no cases (for specified incoming velocities and impact angles considered) can an aluminum projectile penetrate a titanium alloy plate. The ricochet ‘mode predictions ‘obtained from the present simulations agree well with the ricochet ‘mode predictions’ given in an analytical model.

scholarly journals Organic Molecules: Is It Possible to Distinguish Aromatics from Aliphatics Collected by Space Missions in High-Speed Impacts?

Sci ◽  
2020 ◽  
Vol 2 (2) ◽  
pp. 41
Author(s):  
Mark Burchell ◽  
Kathryn Harriss
Keyword(s):  
High Speed ◽  
Organic Molecules ◽  
Chemical Structures ◽  
Surface Ocean ◽  
Life Itself ◽  
Organic Particles ◽  
Open Question ◽  
The Impact ◽  
The Relationship ◽  
Complex Organic

A prime site of astrobiological interest within the Solar System is the interior ocean of Enceladus. This ocean has already been shown to contain organic molecules, and is thought to have the conditions necessary for more complex organic biomolecules to emerge and potentially even life itself. This sub-surface ocean has been accessed by Cassini, an unmanned spacecraft that interacted with the water plumes ejected naturally from Enceladus. The encounter speed with these plumes and their contents, was between 5 and 15 km s−1. Encounters at such speeds allow analysis of vapourised material from submicron-sized particles within the plume, but sampling micron-sized particles remains an open question. The latter particles can impact metal targets exposed on the exterior of future spacecraft, producing impact craters lined with impactor residue, which can then be analysed. Although there is considerable literature on how mineral grains behave in such high-speed impacts, and also on the relationship between the crater residue and the original grain composition, far less is known regarding the behaviour of organic particles. Here we consider a deceptively simple yet fundamental scientific question: for impacts at speeds of around 5–6 kms−1 would the impactor residue alone be sufficient to enable us to recognise the signature conferred by organic particles? Furthermore, would it be possible to identify the organic molecules involved, or at least distinguish between aromatic and aliphatic chemical structures? For polystyrene (aromatic-rich) and poly(methyl methacrylate) (solely aliphatic) latex particles impinging at around 5 km s−1 onto metal targets, we find that sufficient residue is retained at the impact site to permit identification of a carbon-rich projectile, but not of the particular molecules involved, nor is it currently possible to discriminate between aromatic-rich and solely aliphatic particles. This suggests that an alternative analytical method to simple impacts on metal targets is required to enable successful collection of organic samples in a fly-by Enceladus mission, or, alternatively, a lower encounter speed is required.

scholarly journals Organic Molecules: Is It Possible To Distinguish Aromatics From Aliphatics Collected By Space Missions in High-Speed Impacts

Sci ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 12
Author(s):  
Mark Burchell ◽  
Kathryn Harriss
Keyword(s):  
High Speed ◽  
Organic Molecules ◽  
Chemical Structures ◽  
Surface Ocean ◽  
Life Itself ◽  
Organic Particles ◽  
Open Question ◽  
The Impact ◽  
The Relationship ◽  
Complex Organic

A prime site of astrobiological interest within the Solar System is the interior ocean of Enceladus. This ocean has already been shown to contain organic molecules, and is thought to have the conditions necessary for more complex organic biomolecules to emerge and potentially even life itself. This sub-surface ocean has been accessed by Cassini, an unmanned spacecraft that interacted with the water plumes ejected naturally from Enceladus. The encounter speed with these plumes and their contents, was 5 km s−1 and above. Encounters at such speeds allow analysis of vapourised material from submicron-sized particles within the plume, but sampling micron-sized particles remains an open question. The latter particles can impact metal targets exposed on the exterior of future spacecraft, producing impact craters lined with impactor residue, which can then be analysed. Although there is considerable literature on how mineral grains behave in such high-speed impacts, and also on the relationship between the crater residue and the original grain composition, far less is known regarding the behaviour of organic particles. Here we consider a deceptively simple yet fundamental scientific question: for impacts at speeds of around 5−6 kms−1 would the impactor residue alone be sufficient to enable us to recognise the signature conferred by organic particles? Furthermore, would it be possible to identify the organic molecules involved, or at least distinguish between aromatic and aliphatic chemical structures? For polystyrene (aromatic-rich) and poly(methyl methacrylate) (solely aliphatic) latex particles impinging at around 5 km s-1 onto metal targets, we find that sufficient residue is retained at the impact site to permit identification of a carbon-rich projectile, but not of the particular molecules involved, nor is it currently possible to discriminate between aromatic-rich and solely aliphatic particles. This suggests that an alternative analytical method to simple impacts on metal targets is required to enable successful collection of organic samples in a fly-by Enceladus mission, or, alternatively, a lower encounter speed is required.

The Impact of Grinding on Surface Integrity of Powder-Metallurgy High-Speed Steel (S390)

2013 ◽  
Vol 442 ◽  
pp. 52-57 ◽  
Author(s):  
Shan He Mu ◽  
Chuan Liang Cao ◽  
Xiang Lin Zhang ◽  
Zha Xiang ◽  
Xiu Mao
Keyword(s):  
Powder Metallurgy ◽  
Surface Integrity ◽  
High Speed ◽  
White Layer ◽  
Ground Surface ◽  
High Speed Steel ◽  
Residual Stress Field ◽  
Quality Design ◽  
The Impact ◽  
The Relationship

The paper presents an experimental study on the relationship betweenprocess parametersand surface integrity of powder-metallurgy high-speed steel S390 in ultraprecision grinding. The optimal machining parametershave been obtained based on the Taguchi quality design method.The affected layerinduced by ultraprecision grinding has a uniform white layerand an inconspicuous dark layer; there are some carbides in the white layer of some samples; a compressive residual stress field exists on the ground surface. In addition, experiments confirm that lapping can remove the white layer effectively and increase the compressive residual stresses with a growth rate of 65%.The derived results satisfy the real requirements in practice.

Theoretical Model of Surface Roughness for Polishing Super Hard Materials with Abrasive Waterjet

2008 ◽  
Vol 375-376 ◽  
pp. 465-469 ◽  
Author(s):  
Cui Lian Che ◽  
Chuan Zhen Huang ◽  
Jun Wang ◽  
Hong Tao Zhu ◽  
Quan Lai Li
Keyword(s):  
Surface Roughness ◽  
Water Pressure ◽  
Impact Angle ◽  
Abrasive Waterjet ◽  
Abrasive Water Jet ◽  
Hard Materials ◽  
Elastic Distortion ◽  
The Impact ◽  
The Relationship ◽  
Abrasive Size

In this paper, the impact pressure of abrasives acting on the polished materials was deduced by Field Theory and the model of surface roughness for polishing super hard materials with Abrasive Water Jet (AWJ) was established. The model indicates that the surface roughness increases linearly with an increase in the maximum depth of abrasives indenting into materials and that the relationship between the surface roughness and polishing parameters including water pressure, abrasive pressure, the impact angle, the hardness of the polished material, the elastic distortion of abrasive, abrasive size, abrasive density, nozzle diameter and standoff.

scholarly journals Motion Characteristics After Ricochet: An Experimental Investigation

2020 ◽  
Vol 27 (2) ◽  
pp. 4-10
Author(s):  
Guoming Chen ◽  
Junhua Hu ◽  
An Liu ◽  
Jinfu Feng ◽  
Qingqing Hu
Keyword(s):  
High Speed ◽  
Initial Conditions ◽  
Incident Angle ◽  
Linear Functions ◽  
Small Scale ◽  
Residual Velocity ◽  
Angle Change ◽  
Motion Characteristics ◽  
The Stability ◽  
The Relationship

AbstractThe ricochet behaviour of the air–water trans-media vehicle (AWTMV) during water-entry crossing was experimentally investigated. Three types of small-scale AWTMV including cone, ogive, and flat nose were used in the test. The underwater trajectory, velocity, and inclination angle of projectiles during the ricochet process were obtained using a high-speed camera. The angle change of the AWTMV and the ratio of the residual velocity are introduced. Based on this result, the relationship between the ricochet responses and initial conditions was derived. The results of this study show that (1) a small incident angle and great velocity make the occurrence of ricochet behaviour easier, (2) the stability of the trajectory of projectiles with cone, ogive, and flat nose weakened in turn at the same initial conditions, (3) the angle change and the ratio of the residual velocity are linear functions of the incident angle and velocity.

Multi-Body Impact Motion With Friction: Analysis, Simulation, and Experimental Validation

1990 ◽  
Author(s):  
Inhwan Han ◽  
B. J. Gilmore
Keyword(s):  
High Speed ◽  
Video Camera ◽  
Impact Dynamics ◽  
Body System ◽  
High Speed Video Camera ◽  
Multi Body ◽  
The Impact ◽  
Friction Analysis ◽  
Impact Motion

Abstract When a multi-body system collides with a single body or with another multi-body system, impact dynamics with friction should be considered. This paper presents a general computer oriented analysis of impact dynamics incorporating friction. The presence of friction between sliding contacts during the impact makes the problem difficult since the events such as reverse sliding or sticking, which may occur at different times throughout the impact, must be determined. The boundary representations of the bodies are used to solve for the velocities at the points of contact. Using this information and a classification of the modes of impact, the frictional impact with sliding contact problem is solved. Using a high speed video camera, the resulting computer strategy is experimentally verified. Simulation and experimental results agree.

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