TY - JOUR A1 - Brunier-Coulin, F. A1 - Cuéllar, Pablo A1 - Philippe, P. T1 - Erosion onset of a cohesionless granular medium by an immersed impinging round jet T2 - Physical Review Fluids N2 - Among different devices developed quite recently to quantify the resistance to erosion of natural soil within the broader context of dyke safety, the most commonly used is probably the jet erosion test in which a scouring crater is induced by impingement of an immersed water jet. A comprehensive experimental investigation on the jet erosion in the specific situation of a cohesionless granular material is presented here. The tests were performed by combining special optical techniques allowing for an accurate measurement of the scouring onset and evolution inside an artificially translucent granular sample. The impinging jet hydrodynamics are also analyzed, empirically validating the use of a self-similar theoretical framework for the laminar round jet. The critical conditions at the onset of erosion appear to be best described by a dimensionless Shields number based on the inertial drag force created by the fluid flow on the eroded particles rather than on the pressure gradients around them. To conclude, a tentative empirical model for the maximal flow velocity initiating erosion at the bottom of the scoured crater is put forward and discussed in the light of some preliminary results. KW - Jet erosion KW - Cohesionless granular soil KW - Jet hydrodynamics KW - Erosion onset KW - Experimental optical techniques RIM-PLIF PY - 2017 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/39426 AN - OPUS4-39426 SN - 2469-990X VL - 2 IS - 3 SP - Article 034302, 1 EP - 19 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany