A new combined finite element-upwind finite volume method for convection-dominated diffusion problems

2015 ◽  
Vol 32 (3) ◽  
pp. 799-818 ◽  
Author(s):  
Cheng Wang ◽  
Mingyan He ◽  
Pengtao Sun
2016 ◽  
Vol 35 (8) ◽  
pp. 703-706 ◽  
Author(s):  
Rowan Cockett ◽  
Lindsey J. Heagy ◽  
Douglas W. Oldenburg

We take you on the journey from continuous equations to their discrete matrix representations using the finite-volume method for the direct current (DC) resistivity problem. These techniques are widely applicable across geophysical simulation types and have their parallels in finite element and finite difference. We show derivations visually, as you would on a whiteboard, and have provided an accompanying notebook at http://github.com/seg to explore the numerical results using SimPEG ( Cockett et al., 2015 ).


Author(s):  
Lingyu Sun ◽  
Weiwei Chen ◽  
Xiaojie Wang ◽  
Ning Kang ◽  
Bin Xu ◽  
...  

The present paper studied the dynamic response of an underwater system with its navigation plate rotated relative to the main body until it was blocked by an energy absorber. In this process, the relation between fluid-driving moment and speed of main body, as well as the relation between rotation angle of the plate and design parameters of absorber, was investigated through combined finite element method and finite volume method. Before the plate contacted with the energy absorber, it was modeled by linear elastic material, the movement process was solved by finite volume method with dynamic boundary. When the plate started to contact and crash with the absorber, it was modeled by elastic-plastic material, and the interaction of fluid-structure coupling was simulated by explicit finite element method in LSDYNA and finite volume method in FLUENT. The two-way data exchange on the interface between fluid and structure was carried out through equivalent force and moment on each patch of the interface. In addition, the simulation accuracy on large plastic deformation of absorber was verified through a group of drop hammer experiments. After the energy absorber was crushed to ultimate shape, the open angle of plate reached the maximum value and the plate kept relative static to the rigid body. The maximum structural stress and deformation, the opening time and angle of the plate were evaluated by numerical method. It is demonstrated that the proposed method can effectively predict the dynamic response of underwater system under impact loads, and both the absorption capability of the block and the speed of moving body affect the dynamic response history and structural safety.


2013 ◽  
Vol 392 ◽  
pp. 100-104 ◽  
Author(s):  
Fareed Ahmed ◽  
Faheem Ahmed ◽  
Yong Yang

In this paper we present a robust, high order method for numerical solution of multidimensional compressible inviscid flow equations. Our scheme is based on Nodal Discontinuous Galerkin Finite Element Method (NDG-FEM). This method utilizes the favorable features of Finite Volume Method (FVM) and Finite Element Method (FEM). In this method, space discretization is carried out by finite element discontinuous approximations. The resulting semi discrete differential equations were solved using explicit Runge-Kutta (ERK) method. In order to compute fluxes at element interfaces, we have used Roe Approximate scheme. In this article, we demonstrate the use of exponential filter to remove Gibbs oscillations near the shock waves. Numerical predictions for two dimensional compressible fluid flows are presented here. The solution was obtained with overall order of accuracy of 3. The numerical results obtained are compared with experimental and finite volume method results.


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