DebrisInterMixing-2.3: a finite volume solver for three-dimensional debris-flow simulations with two calibration parameters – Part 2: Model validation with experiments

Here, we present validation tests of the fluid dynamic solver presented in von Boetticher et al. (2016), simulating both laboratory-scale and large-scale debris-flow experiments. The new solver combines a Coulomb viscoplastic rheological model with a Herschel–Bulkley model based on material properties and rheological characteristics of the analyzed debris flow. For the selected experiments in this study, all necessary material properties were known – the content of sand, clay (including its mineral composition) and gravel as well as the water content and the angle of repose of the gravel. Given these properties, two model parameters are sufficient for calibration, and a range of experiments with different material compositions can be reproduced by the model without recalibration. One calibration parameter, the Herschel–Bulkley exponent, was kept constant for all simulations. The model validation focuses on different case studies illustrating the sensitivity of debris flows to water and clay content, channel curvature, channel roughness and the angle of repose. We characterize the accuracy of the model using experimental observations of flow head positions, front velocities, run-out patterns and basal pressures

Iatrogenic Pancreatic Cyst Perforation Successfully Managed by a Minimally Invasive Combined Endoscopic–Laparoscopic Approach

Abstract Endoscopic treatment of walled-off pancreatic necrosis is becoming more prevalent in clinical practice, although perforation may complicate 5% of cases, and efficient management of this complication is imperative. In this report, we present a case of necrosis cavity perforation successfully managed by a combined laparoscopic?endoscopic approach, with a novel method of luminal defect closure.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85086/1/lap_2010_0308.pd

DebrisInterMixing-2.3: a finite volume solver for three-dimensional debris-flow simulations with two calibration parameters – Part 1: Model description

Here, we present a three-dimensional fluid dynamic solver that simulates debris flows as a mixture of two fluids (a Coulomb viscoplastic model of the gravel mixed with a Herschel–Bulkley representation of the fine material suspension) in combination with an additional unmixed phase representing the air and the free surface. We link all rheological parameters to the material composition, i.e., to water content, clay content, and mineral composition, content of sand and gravel, and the gravel's friction angle; the user must specify only two free model parameters. The volume-of-fluid (VoF) approach is used to combine the mixed phase and the air phase into a single cell-averaged Navier–Stokes equation for incompressible flow, based on code adapted from standard solvers of the open-source CFD software OpenFOAM. This effectively single-phase mixture VoF method saves computational costs compared to the more sophisticated drag-force-based multiphase models. Thus, complex three-dimensional flow structures can be simulated while accounting for the pressure- and shear-rate-dependent rheology

Verbundprojekt: Grundlegende Charakterisierung von Elektroden für zeitveränderliche Energieeinkopplung in umweltfreundliche Hochdruck-Plasmalampen, Teilvorhaben : Charakterisierung der Übergangsbereiche zwischen Plasma und Elektroden in HID-Lampen : Schlussbericht

[no abstract available

Grundlegende Charakterisierung von Elektroden fuer zeitveraenderliche Energieeinkopplung in umweltfreundliche Hochdruck-Plasmalampen. Teilvorhaben: Charakterisierung der Uebergangsbereiche zwischen Plasma und Elektroden in HID-Lampen Schlussbericht

Available from TIB Hannover: F04B482 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman