Ejecta from Granular-Medium Cratering by a Super-Sonic Jet Entering a Continuum Atmosphere

Hydrogels hold promise in agriculture as reservoirs of water in dry soil, potentially alleviating the burden of irrigation. However, confinement in soil can markedly reduce the ability of hydrogels to absorb water and swell, limiting their widespread adoption. Unfortunately, the underlying reason remains unknown. By directly visualizing the swelling of hydrogels confined in three-dimensional granular media, we demonstrate that the extent of hydrogel swelling is determined by the competition between the force exerted by the hydrogel due to osmotic swelling and the confining force transmitted by the surrounding grains. Furthermore, the medium can itself be restructured by hydrogel swelling, as set by the balance between the osmotic swelling force, the confining force, and intergrain friction. Together, our results provide quantitative principles to predict how hydrogels behave in confinement, potentially improving their use in agriculture as well as informing other applications such as oil recovery, construction, mechanobiology, and filtration.

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Sound Attenuation In A Coarse Granular Medium

Journal of Sound and Vibration ◽

10.1006/jsvi.1993.1137 ◽

1993 ◽

Vol 162 (3) ◽

pp. 529-535 ◽

Cited By ~ 12

Author(s):

D. Wu ◽

Z.W. Qian ◽

D. Shao

Keyword(s):

Granular Medium ◽

Sound Attenuation

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Study of Correctly Expanded Sonic Jet with Air Tabs

International Journal of Turbo and Jet Engines ◽

10.1515/tjj-2020-0005 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Arun Prasad R ◽

Thanigaiarasu S ◽

Sembaruthi M ◽

Rathakrishnan E

Keyword(s):

Numerical Study ◽

Cross Sectional ◽

Potential Core ◽

Convergent Nozzle ◽

Jet Mixing ◽

Pressure Profiles ◽

Constant Diameter ◽

Sonic Jet ◽

Sectional Shape ◽

Length Reduction

AbstractThe present numerical study is to understand the effect of air tabs located at the exit of a convergent nozzle on the spreading and mixing characteristics of correctly expanded sonic primary jet. Air tabs used in this study are two secondary jets issuing from constant diameter tubes located diametrically opposite at the periphery of the primary nozzle exit, normal to the primary jet. Two air tabs of Mach numbers 1.0 to 1.4, in steps of 0.1 are considered in this study. The mixing modification caused by air tabs are analysed by considering the mixing of uncontrolled (free) primary jet as a reference. Substantial enhancement in jet mixing is achieved with Mach 1.4 air tabs, which results in 80 % potential core length reduction. The total pressure profiles taken on the plane (YZ) normal to the primary jet axis, at various locations along the primary jet centreline revealed the modification of the jet cross sectional shape by air tabs. The stream-wise vortices and bifurcation of the primary jet caused by air tabs are found to be the mechanism behind the enhanced jet mixing.

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