High‐speed photography of water drop impacts on sand and soil

2018 ◽  
Vol 70 (2) ◽  
pp. 245-256 ◽  
Author(s):  
N. Lardier ◽  
P. Roudier ◽  
B. Clothier ◽  
G. R. Willmott
Keyword(s):  
High Speed ◽  
Water Drop ◽  
High Speed Photography ◽  
Drop Impacts

Investigating Freely Suspended Water-Drop Interactions with High-Speed Photography

1971 ◽  
Vol 80 (7) ◽  
pp. 557-558
Author(s):  
John D. Spengler ◽  
Narayan R. Gokhale
Keyword(s):  
High Speed ◽  
Water Drop ◽  
High Speed Photography ◽  
Freely Suspended

scholarly journals Probing the nanoscale: the first contact of an impacting drop

2015 ◽  
Vol 785 ◽  
Author(s):  
E. Q. Li ◽  
I. U. Vakarelski ◽  
S. T. Thoroddsen
Keyword(s):  
Solid Surface ◽  
High Speed ◽  
Water Drop ◽  
Triple Line ◽  
Immiscible Liquid ◽  
Initial Contact ◽  
High Speed Imaging ◽  
Left Behind ◽  
Drop Impacts ◽  
First Contact

When a drop impacts onto a solid surface, the lubrication pressure in the air deforms its bottom into a dimple. This makes the initial contact with the substrate occur not at a point but along a ring, thereby entrapping a central disc of air. We use ultra-high-speed imaging, with 200 ns time resolution, to observe the structure of this first contact between the liquid and a smooth solid surface. For a water drop impacting onto regular glass we observe a ring of microbubbles, due to multiple initial contacts just before the formation of the fully wetted outer section. These contacts are spaced by a few microns and quickly grow in size until they meet, thereby leaving behind a ring of microbubbles marking the original air-disc diameter. On the other hand, no microbubbles are left behind when the drop impacts onto molecularly smooth mica sheets. We thereby conclude that the localized contacts are due to nanometric roughness of the glass surface, and the presence of the microbubbles can therefore distinguish between glass with 10 nm roughness and perfectly smooth glass. We contrast this entrapment topology with the initial contact of a drop impacting onto a film of extremely viscous immiscible liquid, where the initial contact appears to be continuous along the ring. Here, an azimuthal instability occurs during the rapid contraction at the triple line, also leaving behind microbubbles. For low impact velocities the nature of the initial contact changes to one initiated by ruptures of a thin lubricating air film.

Erosion Resistance and Its Mechanism for Flame-Hardened 12Cr Steel by High Speed Water Drop Impacts

2006 ◽  
pp. 179-184
Author(s):  
G.H. Kim ◽  
Min Ku Lee ◽  
G.M. Kim ◽  
Sung Mo Hong ◽  
Wheung Whoe Kim ◽  
...  
Keyword(s):  
High Speed ◽  
Erosion Resistance ◽  
Water Drop ◽  
Drop Impacts

Erosion Resistance and Its Mechanism for Flame-Hardened 12Cr Steel by High Speed Water Drop Impacts

2006 ◽  
Vol 118 ◽  
pp. 179-184
Author(s):  
G.H. Kim ◽  
Min Ku Lee ◽  
G.M. Kim ◽  
Sung Mo Hong ◽  
Wheung Whoe Kim ◽  
...  
Keyword(s):  
Steady State ◽  
Incubation Period ◽  
High Speed ◽  
Erosion Resistance ◽  
Water Drop ◽  
Fatigue Cracks ◽  
Flame Hardening ◽  
Erosion Properties ◽  
Drop Impacts ◽  
Impact Erosion

In this study, the water drop impact erosion properties of 12Cr steel surface-hardened by the flame hardening process have been studied. For this, both the maximum erosion depth de,max and volume loss Ve with the number of cumulative impacts n have been investigated for the flame-hardened 12Cr steels with different hardnesses. Typically all the samples showed an erosion-time characteristic involving an incubation period initially followed by a steady state period. Compared to those for the as-received 12Cr steel, the flame-hardened ones showed an excellent erosion resistance to water drop impacts, showing a 2.2~2.8 times higher incubation time ti and 5~8 times lower erosion rate α. In the incubation period the as-received 12Cr steel was deformed by a ductile depression and ploughing, while the flame-hardened one by fatigue cracks and a brittle platelet deformation. In the steady state period the damage was progressed by a cleavage fracture for both the stages.

scholarly journals Compressible air entrapment in high-speed drop impacts on solid surfaces

2013 ◽  
Vol 716 ◽  
Author(s):  
Yuan Liu ◽  
Peng Tan ◽  
Lei Xu
Keyword(s):  
High Speed ◽  
Solid Substrate ◽  
Compressed Air ◽  
Viscous Drag ◽  
High Speed Photography ◽  
Air Entrapment ◽  
Large Pressure ◽  
Drop Impacts ◽  
Air Film ◽  
The Impact

AbstractUsing high-speed photography coupled with optical interference, we experimentally study the air entrapment during a liquid drop impacting a solid substrate. We observe the formation of a compressed air film before the liquid touches the substrate, with internal pressure considerably higher than the atmospheric value. The degree of compression highly depends on the impact velocity, as explained by balancing the liquid deceleration with the large pressure of the compressed air. After contact, the air film expands vertically at the edge, reducing its pressure within a few tens of microseconds and producing a thick rim on the perimeter. This thick-rimmed air film subsequently contracts into an air bubble, governed by the complex interaction between surface tension, inertia and viscous drag. Such a process is universally observed for impacts above a few centimetres high.

High speed photography of the interaction of a water drop with a supersonic sphere

1985 ◽  
Vol 17 (3) ◽  
pp. 148-150 ◽  
Author(s):  
I.A. Dukhovski ◽  
V.A. Komissaruk ◽  
P.I. Kovalev ◽  
N.P. Mende
Keyword(s):  
High Speed ◽  
Water Drop ◽  
High Speed Photography

Crack divergence phenomena in tempered glass

2020 ◽  
Vol 13 (3) ◽  
pp. 115-129
Author(s):  
Shin’ichi Aratani
Keyword(s):  
Optimal Design ◽  
High Speed ◽  
Glass Plate ◽  
Acute Angle ◽  
Divergence Angle ◽  
High Speed Photography ◽  
Tempered Glass ◽  
Thick Glass

High speed photography using the Cranz-Schardin camera was performed to study the crack divergence and divergence angle in thermally tempered glass. A tempered 3.5 mm thick glass plate was used as a specimen. It was shown that two types of bifurcation and branching existed as the crack divergence. The divergence angle was smaller than the value calculated from the principle of optimal design and showed an acute angle.

Experimental study of hydrodynamic effects in the inverse water hydrocarbon emulsions flow in microchannels

2016 ◽  
Vol 11 (1) ◽  
pp. 30-37 ◽  
Author(s):  
A.A. Rakhimov ◽  
A.T. Akhmetov
Keyword(s):  
High Speed ◽  
Petroleum Industry ◽  
Chemical Compounds ◽  
High Viscosity ◽  
Blocking Effect ◽  
High Speed Photography ◽  
Simple Chemical ◽  
Reported Study ◽  
Dynamic Blocking ◽  
Hydrodynamic Effects

The paper presents results of hydrodynamic and rheological studies of the inverse water hydrocarbon emulsions. The success of the application of invert emulsions in the petroleum industry due, along with the high viscosity of the emulsion, greatly exceeding the viscosity of the carrier phase, the dynamic blocking effect, which consists in the fact that the rate of flow of emulsions in capillary structures and cracks falls with time to 3-4 orders, despite the permanent pressure drop. The reported study shows an increase in viscosity with increasing concentration or dispersion of emulsion. The increase in dispersion of w/o emulsion leads to an acceleration of the onset of dynamic blocking. The use of microfluidic devices, is made by soft photolithography, along with high-speed photography (10,000 frames/s), allowed us to see in the blocking condition the deformation of the microdroplets of water in inverse emulsion prepared from simple chemical compounds.

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