A novel phase-field method based numerical approach to modeling the compaction process of sedi- ments is presented. Water-logged rock or soil sediments are deposited on the water basins over time and the increasing volume of the sediment compacts under its own weight and external pressure. Coupled evolution of mass conservation, Darcy flow, and the viscoelastic constitutive response, in conjunction with the evolution of porosity and permeability, make this problem highly non-linear and involve moving boundaries. We adopt a phase-field approach to represent the moving sediment interface, and the underlying multiphasic model permits for studying compaction in dynamically evolving sediments. This approach does not necessitate a change of domain sizes as is the case of existing traditional models of sedimentation but rather treats sedimentation growth as a problem of interface motion. We first model a classical compaction problem in 1D to compare with existing results in the literature, and then extend the framework to 2D to model the compaction process taking place under the influence of gravity. The model is then extensively applied to understand the effect of the sediment initial state and the sediment material properties on the compaction process and its spatiotemporal evolution. Lastly, a strong validation of our phase-field treatment results against predictions from traditional methods of solving open boundary sediment compaction problems, and a good agreement between the conventional understanding and the numerical predictions of porosity dependence on the fluid pore pressure for various cases of geological interest, are used to demonstrate the applicability and scalability of this novel numerical framework to model more advanced sediment compaction problems and geometries.
With the increasing proportion of cable lines in the distribution network, the capacitance current in the system increases, which leads to the single phase to ground arcing fault in the distribution network. However, at present, there is less research on single phase to ground arcing fault, and the type of grounding fault is always assumed to be metallic or resistive grounding, and the arcing ground fault is not identified in time, which leads to further expansion of the fault. In this paper, the transient simulation analysis of a single phase to the ground is carried out, and a new method to distinguish arcing ground fault from metal grounding fault using wavelet packet energy is proposed, which solves the problem of fault type identification. Through a large number of simulation data analyses and practical verification, it is shown that the method is not affected by the time of fault occurrence and neutral grounding mode, and has a strong anti-interference ability and high reliability.
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