Effect of viscosity contrast on plume formation in density stratified fluids

We perform two and three dimensional numerical simulations of plume formation in density and viscosity stratified fluid systems. We show that the ambient to plume fluid viscosity ratio strongly affects the near wall plume structures (line or sheet plumes) such as plume spacing and shape of plumes. We observe that where mushroom-like plumes are observed for lower viscosity ratios, taller plumes with bulbous heads form for high viscosity ratios. Plume structure and spacing are in good agreement with experimental results. By studying the geometry of the line plumes and the flow in the circulation cells, we discuss the mechanisms of their formation and the dynamics of merging. We show that an increase in the viscosity ratio decreases the total length of line plumes in the planform which indicates a decreased mixing at higher viscosity ratios. (C) 2015 Elsevier Ltd. All rights reserved.

Joint Strength and Wall Deformation Characteristics of a Single-Cell Geocell Subjected to Uniaxial Compression

Geocells are three-dimensional expandable panels with a wide range of applications in geotechnical engineering. A geocell is made up of many internally connected single cells. The current study discusses the joint strength and the wall deformation characteristics of a single cell when it is subjected to uniaxial compression. The study helps to understand the causes for the failure of the single cell in a cellular confinement system. Experimental studies were conducted on single cells with cell pockets filled up with three different infill materials, namely silty clay, sand, and the aggregates. The results of the experimental study revealed that the deformation of the geocell wall decreases with the increase in the friction angle of the infill material. Experimental results were also validated using numerical simulations carried out using Lagrangian analysis software. The experiment and the numerical results were found to be in good agreement with each other. A simple analytical model based on the theory of thin cylinders is also proposed to calculate the accumulated strain of the geocell wall. This model operates under a simple elastic solution framework. The proposed model slightly overestimates the strains as compared with experimental and numerical values. (C) 2014 American Society of Civil Engineers.