@article{WOS:000896588700001,

title = {On the erosion of cohesive granular soils by a submerged jet: a 

 numerical approach},

author = {Zeyd Benseghier and Li-Hua Luu and Pablo Cuellar and Stephane Bonelli and Pierre Philippe},

doi = {10.1007/s10035-022-01289-5},

issn = {1434-5021},

year  = {2023},

date = {2023-02-01},

journal = {GRANULAR MATTER},

volume = {25},

number = {1},

abstract = {This paper presents an erosion interpretation of cohesive granular 

 materials stressed by an impinging jet based on the results of a 

 micromechanical simulation model. The numerical techniques are briefly 

 described, relying on a two-dimensional Lattice Boltzmann Method coupled 

 with a Discrete Element Methods including a simple model of solid 

 intergranular cohesion. These are then used to perform a parametric 

 study of a planar jet in the laminar regime impinging the surface of 

 granular samples with different degrees of cohesive strength. The 

 results show the pertinence of using a generalized form of the Shields 

 criterion for the quantification of the erosion threshold, which is 

 valid for cohesionless samples, through empirical calibration, and also 

 for cohesive ones. Furthermore, the scouring kinetics are analysed here 

 from the perspective of a self-similar expansion of the eroded crater 

 leading to the identification of a characteristic erosion time and the 

 quantification of the classical erosion coefficient. However, the 

 presented results also challenge the postulate of a local erosion law 

 including erodibility parameters as intrinsic material properties. The 

 paper then reviews the main limitations of the simulation and current 

 interpretation models, and discusses the potential causes for the 

 observed discrepancies, questioning the pertinence of using 

 time-averaged macroscopic relations to correctly describe soil erosion. 

 The paper concludes addressing this question with a complementary study 

 of the presented simulations re-assessed at the particle-scale. The 

 resulting local critical shear stress of single grains reveals a very 

 wide dispersion of the data but nevertheless appears to confirm the 

 general macroscopic trend derived for the cohesionless samples, while 

 the introduction of cohesion implies a significant but systematic 

 quantitative deviation between the microscopic and macroscopic 

 estimates. Nevertheless, the micro data still shows consistently that 

 the critical shear stress does actually vary approximately in linear 

 proportion of the adhesive force.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lemasquerier_2023,

title = {Zonal jets experiments in the gas giants' zonostrophic regime},

author = {D. Lemasquerier and B. Favier and M. Le Bars},

url = {https://doi.org/10.1016%2Fj.icarus.2022.115292},

doi = {10.1016/j.icarus.2022.115292},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

journal = {Icarus},

volume = {390},

pages = {115292},

publisher = {Elsevier BV},

abstract = {Intense east-west winds called zonal jets are observed in the atmospheres of Jupiter and Saturn and extend in their deep interior. We present experimental results from a fully three-dimensional laboratory analog of deep gas giants zonal jets. We use a rapidly rotating deep cylindrical tank, filled with water, and forced by a small-scale hydraulic circulation at the bottom. A topographic β-effect is naturally present because of the curvature of the free surface. Instantaneous turbulent zonal jets spontaneously emerge from the small-scale forcing, equilibrate at large scale, and can contain up to 70% of the total kinetic energy of the flow once in a quasi-steady state. We show that the spectral properties of the experimental flows are consistent with the theoretical predictions in the zonostrophic turbulence regime, argued to be relevant to gas giants. This constitutes the first fully-experimental validation of the zonostrophic theory in a completely three-dimensional framework. Complementary, quasi-geostrophic (QG) simulations show that this result is not sensitive to the forcing scale. Next, we quantify the potential vorticity (PV) mixing. While PV staircasing should emerge in the asymptotic regime of the gas giants, only a moderate PV mixing occurs because of the strong forcing and dissipation, as confirmed by QG simulations at smaller Ekman number. We quantify the local PV mixing by measuring the equivalent of a Thorpe scale, and confirm that it can be used to estimate the upscale energy transfer rate of the flow, which otherwise needs to be estimated from a much more demanding spectral analysis. },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000860284900009,

title = {Breakups of Chitosan microcapsules in extensional flow},

author = {Revaz Chachanidze and Kaili Xie and Jinming Lyu and Marc Jaeger and Marc Leonetti},

doi = {10.1016/j.jcis.2022.08.169},

issn = {0021-9797},

year  = {2023},

date = {2023-01-01},

journal = {JOURNAL OF COLLOID AND INTERFACE SCIENCE},

volume = {629},

number = {A},

pages = {445-454},

abstract = {The controlled rupture of a core-shell capsule and the timely release of 

 encapsulated materials are essential steps of the efficient design of 

 such carriers. The mechanical and physico-chemical properties of their 

 shells (or membranes) mainly govern the evolution of such systems under 

 stress and notably the link between the dynamics of rupture and the 

 mechanical properties. This issue is addressed considering weakly 

 cohesive shells made by the interfacial complexation of Chitosan and 

 PFacid in a planar extensional flow. Three regimes are observed, thanks 

 to the two observational planes. Whatever the time of reaction in 

 membrane assembly, there is no rupture in deformation as long as the 

 hydrodynamic stress is below a critical value. At low times of 

 complexation (weak shear elastic modulus), the rupture is reminiscent of 

 the breakup of dro-plets: a dumbell or a waist. Fluorescent labelling of 

 the membrane shows that this process is governed by continuous thinning 

 of the membrane up to the destabilization. It is likely that the 

 membrane shows a tran-sition from a solid to liquid state. At longer 

 times of complexation, the rupture has a feature of solid-like breakup 

 (breakage) with a discontinuity of the membrane. The maximal internal 

 constraint determined numerically marks the initial location of breakup 

 as shown. The pattern becomes more complex as the elon-gation rate 

 increases with several points of rupture. A phase diagram in the space 

 parameters of the shear elastic modulus and the hydrodynamic stress is 

 established.(c) 2022 Elsevier Inc. All rights reserved.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}