Parallel Block Adaptive Mesh Refinement For Multiphase Flows
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Transcript of Parallel Block Adaptive Mesh Refinement For Multiphase Flows
Parallel Block Adaptive Mesh Refinement For Multiphase Flows
D. Zuzio*J-L. Estivalezes*
*ONERA/DMAE, 2 av. Édouard Belin, 31055 Toulouse, France
Simulation of a Rayleigh-Taylor instability with five levels of adaptive mesh
Elliptic solver
Numerical method - AMR
Context
The study of liquid-gas interactions have a fundamental importance, especially in combustion problems. The interfacial instabilities, like the Kelvin-Helmholtz, produce the droplets or sprays that afterwards participate to combustion. In particular where experiments are too difficult or expensive to perform, the numerical simulation becomes a powerful tool for predicting these physical phenomena. The direct numerical simulation (DNS) gives a "model free" approach to the Navier Stokes equations, at the price, however, of a higher computational resources demand.
BibliographyKevin Olson. Paramesh: A parallel adaptive grid tool. in Parallel Computational Fluid Dynamics 2005: Theory and Applications: Proceedings of the Parallel CFD Conference, College Park, MD, U.S.A., eds. A. Deane, A. Ecer, G. Brenner, D. Emerson, J. McDonough, J. Periaux, N. Satofuka, and D. Tromeur-Dervout (Elsevier), 2006.M. Sussman. A parallelized, adaptive algorithm for multiphase flows in general geometries. Computers and Structures, 2005.R. Teigland and I. K. Eliassen. A multiblock/multilevel mesh refinement procedure for cfd computations. International journal for numerical methods in fluids, 2001.H. A. VanDerVorst. Bi-CGstab: a fast and smoothly converging variant of bi-cg for the solution of nonsymmetric linear systems. SIAM Journal of Scientific Computing, 1992,11.
Conclusions & PerspectivesA global second order explicit projection method for incompressible two phase flows has been improved with parallel adaptive mesh refinement. The ability to perform high density ratio computations has been demonstrated, in particular the capability of the elliptic solver to converge for all the test cases. With local interface refinement an AMR simulation can nearly achieve the fine grid precision, thus allowing great computational resources saving.AcknowledgementsThis research project has been supported by a Marie Curie Early Stage Research Training Fellowship of the European Community Sixth Framework Program under contract number MEST-CT-2005-020426.
Background: Study of complex interfacial flows Example: Atomization of fuel in combustion chambers
Objectives: Realization of DNS simulations Perform parallel computations Use of adaptive mesh refinement to allow high
resolutions
* http://www.physics.drexel.edu/~olson/paramesh-doc/Users_manual/amr.html
PARAMESH* package Quad-tree block type AMR Parallel workload balance Coarse-fine interface managing Allows multigrid
Resolution of Navier Stokes equations Resolution in each fluid Incompressible flows hypothesis Explicit projection method
Interface tracking Two non-miscible fluids Level-Set method Immediate knowledge of interface position and geometry
Jump conditions Ghost-Fluid method Jumps always evaluated
on the finest mesh
Results
Adaptive Mesh Refinement “Near interface” refinement criterion:
the mesh refines automatically when the proximity of the interface is detected
Experimental study of the disintegration of a liquid sheet, H. Carentz, ONERA
BiCG-Stab Strong density ratio flows Unsymmetrical linear systems Local block matrix strategy Preconditioning
FAC multigrid preconditioner Use of tree blocks for multigrid Fast Adaptive Composite grid algorithm
Rebyax
e222
22 )()(
numericalanaliticalerr
l0 l1 l2 l3Use of AMR tree for multigrid preconditioner