1,721,041 research outputs found
Boundary element method calculation of pipe features for a fracture network
Full text linkThe boundary element method (BEM) is utilized to estimate pipe conductances for discrete fracture networks under steady-state flow. Pipes connects midpoints fracture traces within a fracture and transform a complex three-dimensional network into a simpler ID problem. Each trace is considered to be a slit of no width. Each fracture is individually analyzed under a particular boundary condition and global fluid exchange are calculated in order to define pipe conductances. Using this formulation pipe network geometries are efficiently and precisely calculated by the BEM. Comparisons with full discretized FEM results are shown
A BEM Code for Ground‐Water Problems in Multizoned Domains with Normal Boundary Flux Discontinuities
No full textA numerical code which utilizes the boundary element method (BEM) for solving steady-state ground-water flow problem is illustrated. The paper concentrates on accuracy in studying situations which are generally considerd to involve some mathematical difficulty, such as zoned domains and flux discontinuities. A numerical BEM code is proposed, the main features of which involves accurately calculating flux discontinuities using a structure particularly flexible in multizoned domains. Two examples are reported, the results of which are comparable with those available in the literature
Derivation of equivalent pipe network analogues for 3D discrete fracture networks by the boundary element method
No full textA BEM solution of steady-state flow problems in discrete fracture networks with minimization of core storage
No full textA BEM code for ground water problems in multizoned domains with normal boundary flux discontinuities
No full textAnalisi di rischio per la fattibilità di uno stoccaggio geologico di anidride carbonica
No full textDerivation of equivalent pipe network analogues for three-dimensional discrete fracture networks by the boundary element method
No full textDiscrete fracture network (DFN) models generally require solution of flow and
transport equations in three-dimensional networks of either disc, polygonal, or pipe
elements. Pipe network elements have significant advantages in computation for both flow
and transport. However, there is a need to develop an efficient procedure for derivation of
the properties of these pipes to ensure that they are hydraulically equivalent to the DFN
network of polygonal elements. In this study a boundary element procedure for derivation
of pipe properties is developed and demonstrated. The results show that the hydraulic
behavior of pipe networks can be equivalent to that of polygonal-element DFN models
A BEM solution of steady-state flow problems in discrete fracture networks with minimization of core storage
No full textA boundary element method (BEM) solution for the problem of the fluid flow in a three-dimensional discrete fracture
network (DFN) is proposed. A DFN is an assembling of polygons which resemble the fractures in a rock mass. The
position, extension, orientation and transmissivity of each fracture of the network are excluded by specific statistical
distributions. For a single problem, a significant number of DFNs has to be generated and the fluid flow has to be
assessed in each of them in the context of a Monte-Carlo procedure. Even for relatively small domains, a DFN may
include a large number of fractures. As a consequence, in order to solve the whole problem with standard finite-element
method (FEM) codes, a big amount of core memory and large input data files are required. The main advantage of the
proposed solution is mainly the minimization of the core memory. This is attained by handling the flow quantities in
such a way the equation system of the overall network is never assembled. Only a relation per each fracture among
nodal fluxes and heads of the traces (i.e., intersections among fractures) is defined and stored in a random access file.
This relation is obtained by means of the application of the BEM to each single fracture of the network. Both constant
and quadratic element representations are used in order to define the relevant nodal quantities. The use of constant
elements allows to avoid the direct treatment of the points of flux discontinuity. No special care is applied to the
discretization of the boundary of each fracture. The overall problem is solved by means of an iterative procedure, by
retrieving the necessary coefficients from the random access file. The results are in acceptable agreement with the ones
provided by a commercial FEM code. We remark that saving core memory without special care in the discretization of
the DFN makes the solution competitive, especially when dealing with networks with a high number of fractures
- …
