Structures - Parallel Programming Laboratory - University of Illinois ...

busyicicleMécanique

22 févr. 2014 (il y a 3 années et 3 mois)

61 vue(s)

Future Plans

Michael T. Heath

Professor and Director

12 September 2001

©2001 Board of Trustees of the University of Illinois

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
2

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Y6
-
10


Multiscale simulations


Improved physical modeling


Multiphysics coupling


Verification and validation

3

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Fluid Dynamics

4

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Two
-
Phase Flow

Burning Aluminum with Smoke








Crude droplet burning model


No support for slag build
-
up


No subgrid effects for particles,
combustion, etc.


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Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Validation

of

Rocturb


Ad hoc turbulence injection model


No two
-
phase flow effects in model


Simple subgrid models


Inadequate agreement with experimental
turbulence data

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Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Fluids


Multiscale Simulations


Spatial multiscale: Generalized LES


Further “Optimal LES” turbulence development


Combustion “LES”


Radiation “LES”


Lagrangian particles and super particles


Temporal multiscale


Time zooming formulations


High order, high resolution, optimal
numerics (for LES)


Adaptive grids for turbulence simulation

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Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Fluids


Improved Physical Modeling


Real gas effects



Thermal and chemical non
-
equilibrium


Nozzle and plume physics


Aluminum particle combustion


Based on detailed single
-
particle simulations


Acoustic coupling


Hydrodynamic instabilities


Combustion instabilities


Multi
-
phase flow


Slag accumulation


Agglomeration and break
-
up

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Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Fluids


Multiphysics Coupling


Injection from combustion layer


Turbulent fluctuations


Aluminum droplets


Particle combustion


Fluid
-
structure in deforming/complex
geometry


Inhibitor and crack propagation


Hybrid structured/unstructured grid


Inhibitor and nozzle scouring and
ablation


Grid generation, motion, and remeshing

9

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Fluids


V&V


Automated verification test suite


Regular periodic testing of developing code


Expanding domain of testing


Component model validation against DNS


LES & CPR


Particle combustion and single
-
particle DNS


Characterizing solution uncertainties


Uncertainties from modeling, input data, numerics


Integration of physical data


Simulation validation against available data


NASA, Thiokol, ONERA, …

10

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Fluids


Experiments


Optical flow
measurements in
propellant combustion
flow


Turbulence and particle
distribution

Detailed fluid measurements in
combustion
-
driven flows

11

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Combustion and

Energetic Materials

12

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

f(x,y,t)
z



Current: single
-
valued

Level sets/ghost fluid?
(collaboration with CS)


Future: multivalued

CEM


Surface Propagation

13

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

CEM


Turbulence Seeding

Time
-
dependent
mass flux from
propellant provides
boundary conditions
for turbulent
chamber flow

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Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

CEM


Multiscale Simulations


Average 3
-
D condensed phase equation
to get 1
-
D model


Use
Rocfire

to modify
Rocburn


Use DNS to construct models for averaged terms


Turbulence seeding


Erosive burning

4
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15

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

CEM


Improved Physical Modeling


Complex kinetics


Gas
-
phase


Condensed
-
phase


Level
-
set methods for
steep or over
-
hanging
propellant surfaces


Fuel
-
rich packs


Aluminum pooling and injection

16

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

CEM


Multiphysics Coupling


Effects of flow on burning


Erosive burning


Ignition transients and flame spread


Turbulence seeding


Injection of igniting aluminum droplets


Burning in cracks


Surface propagation

17

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

CEM


V&V


Sandwich
-
propellant experiments


Flame structure


Surface structure


Regression rate


Composite
-
propellant data


Average regression rate


Unsteady response, pressure coupling

18

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois



CEM


Multiscale Simulations


Path integral Monte Carlo for thermal
simulations of quantum systems


Ab initio molecular dynamics (Car
-
Parrinello) simulations of materials


Excited states and quantum reaction
dynamics in molecules


Combining the methods


Thermal simulations of matter using quantum
Monte Carlo


First principles calculations of reaction dynamics


Density functional simulations for large systems

High pressure non
-
molecular phase of
nitrogen
-

density
functional simulation
-

compared with
experiments

Nature 411, 170 (2001)

CEM


Multiscale Simulations

Shock data for hydrogen

comparison of PIMC simulations
with NOVA laser shock
experiments and SESAME EOS.


Science 281, 1178, 1998.

Decomposition pathways

of ethylene

Embedding

Force models

Continuum mechanics

Extend to

heavier atoms

Longer time

scales

Longer time

scales

20

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

CEM


Improved Physical Modeling


Improved methods


Improved functionals using quantum Monte Carlo methods


Extending quantum Monte Carlo to heavier atoms


Embedding of methods for multiscale simulations


Reaction dynamics calculations embedded in regions simulated
by density functionals and continuum mechanics


Time scale
-

the hardest problem


Hyperdynamics and beyond for atomic scale simulations


Integration into kinetic Monte Carlo for reactions

21

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Structures and

Materials

Constitutive Modeling of SP


Currently: Arruda
-
Boyce


8
-
chain rubber elasticity model


Developed for unfilled and filled
rubbery materials


Nonlinear kinematics


Material stiffening


Simplicity



Still missing


Rate dependence (Bergstrom
-
Boyce)


Microstructural damage and
fracture mechanisms


Dewetting


Void growth


Binder tearing


Integration of multiscale models

30

20

10

1.0

2.0

3.0

4.0

5.0

Stretch

Nominal stress

(MPa)

23

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Structures


Multiscale Simulations


Molecular, granular, and structural
modeling of case and SP


Adaptivity in
Rocsolid

and
Rocfrac


Spatial adaptivity through mesh refinement


Dynamic remeshing and repair


Dynamic insertion of cohesive elements


Implementation of 4
-
D space
-
time FE
scheme

24

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Structures

Improved Physical Modeling


Implement history
-
dependent constitutive
models in ALE
formulation


Extend SP constitutive
theory to failure regime


Modeling of nozzle
ablation and scouring

25

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Structures


Multiphysics Coupling


Mesoscale structure/combustion
modeling of advancing crack


Macroscale modeling of fracture events
with
Rocflu/Rocfrac


Mesh generation


Implicit/explicit coupling strategies

26

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Structures


V&V


Benchmark verification problems


Expand library of known benchmark problems


Develop methods to create new benchmark
problems to test complicated modules (e.g., ALE)


Verification of coupled codes


Validate codes


Thiokol failure data on model SP motors


Lab
-
scale rocket data


Quasi
-
static and dynamic properties of SP and case
(D6AC steel) under tension and compression


Methods to deal with model uncertainty
and sensitivity

27

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Computer Science

28

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Software Framework Challenges


Full exploitation of object decomposition


Load balance within individual phases


Source code changes for AMPI


10K
-
100K processors


Inadequate load balancing strategies


Automatic optimization of object communication


Component frameworks


Dynamic insertion support for FEM


Component frameworks for other common abstractions


Integration of modules


Complex orchestration code


Optimized parallel data exchange

29

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

CS


Frameworks


Software integration


Intelligent interface between modules


Intelligent handling of dynamic
behavior


Adaptivity


Load
-
balancing


Support for choice of coupling
strategies


Support for spawning subscale
simulations


Components


Application
-
aware data structures


FEM, multiblock, AMR, particles, …

Solid

HDF IO

Fluid

Roccom

Orchestration

Combustion

Interface

30

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

CS


Computational Infrastructure


Computational steering


Autopilot


On
-
the
-
fly performance
analysis and visualization


Pablo


Panda/Globus

integration
for Grid


Remote visualization of
ultra large data sets


Scalability issues for
100K processors

31

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Challenges in Computational
Mathematics and Geometry


Independent meshing capability


Mesh adaptation and repair


Robust and efficient propagation
of moving interface in 3
-
D


Interpolation extended to 3
-
D for
remeshing, etc.


Robust and scalable solvers for
ill
-
conditioned, nonsymmetric
systems


32

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

CS

Improved Computational Techniques


Computational geometry


Dynamic mesh repair


On
-
the
-
fly remeshing


Interpolation between 3
-
D meshes


Interface surface propagation in 3
-
D


Computational mathematics


Iterative solvers for ill
-
conditioned systems


Application
-
specific preconditioners


Grid
-
based solvers


33

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Integrated

Simulations

34

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

GEN3


Multiscale simulations


Homogenization


Time zooming


Dynamically
-
spawned subscale simulations


Improved physical modeling


Propellant ignition and tailoff


Real gas effects


Slag formation


Nozzle and inhibitor ablation and scouring


Plume


Environmental effects

35

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

GEN3


Multiphysics coupling


Modules coupled using SWIFT


External modules (inbound)


Technology transfer (outbound)


V&V


Normal burns


Accident scenarios


Thrust vector control (3
-
D effects)


Additional rocket designs


NASA five
-
segment Shuttle booster


Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

http://www.csar.uiuc.edu

©

37

Center for Simulation of Advanced Rockets
University of Illinois at Urbana-Champaign
©2001 Board of Trustees of the University of Illinois

Michael T. Heath, Director

Center for Simulation of Advanced Rockets

University of Illinois at Urbana
-
Champaign

2262 Digital Computer Laboratory

1304 West Springfield Avenue

Urbana, IL 61801 USA



m
-
heath@uiuc.edu

http://www.csar.uiuc.edu

telephone: 217
-
333
-
6268

fax: 217
-
333
-
1910