Recent advances in the particle finite element method. Towards more complex fluid flow applications
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Estadístiques de LA Referencia / Recolecta
Inclou dades d'ús des de 2022
Cita com:
hdl:2117/192668
Tipus de documentText en actes de congrés
Data publicació2013
EditorCIMNE
Condicions d'accésAccés obert
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Abstract
One of the main drawbacks of the explicit integration using Eulerian formulations
is the restricted stability of the solution with the time steps and with the spatial discretization.
For the case of the Navier-Stokes equations, it is well known that the time step to be used in
the solution is stable only for time step smaller than two critical values: the Courant-
Friedrichs-Lewy (CFL) number and the Fourier number. The first one is concerning with the
convective terms and the second one with the diffusive ones. Both numbers must be less than
one to have stable algorithms. For convection dominant problems like high Reynolds number
flows, the condition CFL<1 becomes crucial and limit the use of explicit method or
outdistance it to be efficient. On the other hand, implicit solutions using Eulerian
formulations is restricted in the time step size due to the lack of convergence of the convective
non-linear terms. Both time integrations, explicit or implicit are, in most cases, limited to CFL
no much larger than one. The possibility to perform parallel processing and the recent
upcoming of new processors like GPU and GPGPU increase the possibilities of the explicit integration in time due to the facility to parallelize explicit methods having results with speedup
closed to one. Although the incompressible condition cannot be solved explicitly, the
solution of the momentum conservation equations with an explicit integration of the
convective terms together with a parallel processing reduces considerably the computing time
to solve the whole problem provided that a large time-step may be preserved independently to
the discretization in space. Only to remember the new Particle Finite Element Method, called
PFEM 2nd generation (PFEM-2) uses a Lagrangian formulation with an explicit time
integrator without the CFL<1 restriction for the convective terms. This allows large timesteps,
independent of the spatial discretization, having equal or better precision that an
implicit integration. Moreover, PFEM-2 has two versions, one for moving mesh with
permanent remeshing and one for fixed mesh [1]. In this lecture we will present some recent
advances in the Particle Finite Element Method (PFEM) to solve the incompressible Navier-
Stokes equations coupled with another fields like in multiphysics exploiting some nice features
found in the fixed version. On the other hand we will also present the moving mesh version
applied to multifluids using a parallel remeshing that makes this efficient in terms of cpu time.
This updated proposal will be tested numerically and compared in terms of accuracy as in
computing cpu time with other more standard Eulerian formulations.
ISBN978-84-941407-6-1
Fitxers | Descripció | Mida | Format | Visualitza |
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Coupled-2013-86_Recent advances in he particle.pdf | 1,258Mb | Visualitza/Obre |