scholarly journals An Unfitted Finite Element Method for Two-Phase Stokes Problems with Slip Between Phases

2021 ◽  
Vol 89 (2) ◽  
Author(s):  
Maxim Olshanskii ◽  
Annalisa Quaini ◽  
Qi Sun
2013 ◽  
Vol 712-715 ◽  
pp. 1027-1031
Author(s):  
Zhen Yu Liu ◽  
Ping Ping Zhang ◽  
Hu Zhen Wang ◽  
Xiang Rong Zhu

Aimed at deflection fracturing by oriented perforation, a two-dimensional, non-steady and two-phase Finite Element Method (FEM) is established. Taking a battery of wells in the inverted nine-spot rhombus pattern as object of study, it is reported that law of different crack initiation angle (CIA) affecting deflection fracturing. In the respect of daily oil production and cumulative oil production, the dual fracture with different CIA is more than straight fracture. So it is feasible to use deflection fracturing of oriented perforation to increase the production of the special low permeability oilfield. In contrast to dual fractures with different fracturing initiation angles, we can see that the wider CIA, the higher cumulative oil production. So we can draw such a conclusion that when deflection fracturing is implemented, angle should be increased if the working condition is permitted so as to increase the production of oil well.


Author(s):  
Xuejuan Li ◽  
Ji-Huan He

Purpose The purpose of this paper is to develop an effective numerical algorithm for a gas-melt two-phase flow and use it to simulate a polymer melt filling process. Moreover, the suggested algorithm can deal with the moving interface and discontinuities of unknowns across the interface. Design/methodology/approach The algebraic sub-grid scales-variational multi-scale (ASGS-VMS) finite element method is used to solve the polymer melt filling process. Meanwhile, the time is discretized using the Crank–Nicolson-based split fractional step algorithm to reduce the computational time. The improved level set method is used to capture the melt front interface, and the related equations are discretized by the second-order Taylor–Galerkin scheme in space and the third-order total variation diminishing Runge–Kutta scheme in time. Findings The numerical method is validated by the benchmark problem. Moreover, the viscoelastic polymer melt filling process is investigated in a rectangular cavity. The front interface, pressure field and flow-induced stresses of polymer melt during the filling process are predicted. Overall, this paper presents a VMS method for polymer injection molding. The present numerical method is extremely suitable for two free surface problems. Originality/value For the first time ever, the ASGS-VMS finite element method is performed for the two-phase flow of polymer melt filling process, and an effective numerical method is designed to catch the moving surface.


Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3744
Author(s):  
Jichao Han ◽  
Baojun Ge ◽  
Kai Zhang ◽  
Yang Wang ◽  
Chao Wang

To investigate the influence of control and structure parameters on the starting performance of a switched reluctance motor, a 12/8 pole switched reluctance motor is analyzed in this paper. The novel field-circuit coupled finite element method of switched reluctance motor is proposed in the paper. The influence of the controller on the switched reluctance motor is considered. The influence of rotor initial position angle, starting mode, starting current, and structure parameters on the starting performance of the switched reluctance motor is studied using the field-circuit coupled finite element method. The starting performance of the switched reluctance motor is obtained under the different control and structure parameters. The alternating starting mode of single- and two-phase winding can improve the starting torque of switched reluctance motor (SRM). As the stator pole arc coefficient increases, the starting torque of SRM increases. The appropriate reduction of the air gap length can improve the starting torque of SRM. Experimental results of the prototype are compared with the calculation results, which verifies the reliability of the calculation method and accuracy of the calculation results.


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