Air is injected locally at the base of an immersed granular bed. The gas, which is forced to flow gently through the material, creates several paths between the grains. We observe that the latter gas venting results in the emission of bubbles in a localized region at the free surface. Additional experiments, performed in two dimensions, permit a direct visualization of the paths, and a theoretical approach shows that the typical size of the region at the free surface can be accounted for by a diffusionlike process. The diffusion coefficient is expressed as a function of the system parameters.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1103/PhysRevE.83.011302 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Rheology of granular particles immersed in a molecular gas under uniform shear flow.
Phys Rev E
June 2024
Departamento de Física and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, E-06006 Badajoz, Spain.
Non-Newtonian transport properties of a dilute gas of inelastic hard spheres immersed in a molecular gas are determined. We assume that the granular gas is sufficiently rarefied, and hence the state of the molecular gas is not disturbed by the presence of the solid particles. In this situation, one can treat the molecular gas as a bath (or thermostat) of elastic hard spheres at a given temperature.
View Article and Find Full Text PDFDrag force regime in dry and immersed granular media.
Phys Rev E
June 2024
School of Civil Engineering, Suzhou University of Science and Technology, Suzhou 215009, China.
The drag force acting on an intruder colliding with granular media is typically influenced by the impact velocity and the penetrating depth. In this paper, the investigation was extended to the dry and immersed scenarios through coupled simulations at different penetrating velocities. The drag force regime was clarified to exhibit velocity dependence in the initial contact stage, followed by the inertial transit stage with a F∼z^{2} (force-depth) relationship.
View Article and Find Full Text PDFDynamical force measurements for contacting soft surfaces upon steady sliding: Fixed-depth tribology.
Phys Rev E
June 2024
Institute of Physics, Academia Sinica, Taipei 115201, Taiwan.
The tribology between surfaces can have a profound impact on the response of a mechanical system, such as how granular particles are driven to flow. In this work, we perform experiments that time resolve the tangential and normal components of the force between two semicylindrical polydimethylsiloxane samples immersed in fluid, as they slide against each other in a range of controlled speeds. The time-averaged friction force shows a nonmonotonic dependence on the sliding speed over four decades, which is consistent with the paradigmatic Stribeck diagram and three dynamical regimes associated with it.
View Article and Find Full Text PDFThermal measurements of boiling granular films.
Rev Sci Instrum
May 2024
Arctic Greenhouse Research Unit (AGRU), Ounasjoen itapuolentie 5617, Meltaus, 97340 Rovaniemi, Finland.
This study focused on two familiar items in our daily lives: grains and boiling water. Accurately measuring boiling dense granular beds requires specialized instruments and novel techniques. An annular vertical riser was used to boil granular films.
View Article and Find Full Text PDFLittle Ironweed and Java Tea in Herbal Toothpaste Reduced Dentine Permeability: An Study.
J Int Soc Prev Community Dent
February 2024
Research office, Faculty of Dentistry, Mahidol University, Bangkok, Thailand.
Aim: To determine the effect of an herbal toothpaste containing Little Ironweed and Java Tea, on reducing dentine permeability .
Materials And Methods: Dentine discs from human mandibular third molars were divided into three groups and brushed with herbal toothpaste, nonherbal toothpaste, or deionized water. Each group was immersed in artificial saliva (AS) or 6% citric acid.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!