vista: a multi -field object oriented cfd -package · 3. nafems cfd-seminar wiesbaden, 08.-09. mai...

3. NAFEMS CFD-Seminar Wiesbaden, 08.-09. Mai 2006

Vista: A MultiVista: A Multi --field Object Oriented field Object Oriented CFDCFD--packagepackage

T. Kvamsdal1, R. Holdahl1 and P. Böhm2

1SINTEF ICT, Applied Mathematics, Norway2inuTech GmbH, Germany


Outline

• inuTech & SINTEF

• VISTA – a CFD Solver

• VISTA – a CFD Toolbox

• Extrusion example: Extrud3D


inuTech - Our Object

Closing the Gap between

Engineering and Mathematics

to Solve Engineering and

Mathematical Problems

R&D of Numerical Methods Sales and Support of

Software

R&D of Numerical Methods Sales and Support of

Software

Seminars and Training Seminars and Training

Consulting Consulting

inuTech - Our Objectives


Univ. of Oslo

Univ. of Erlangen

Univ. of Bayreuth

The Team

(resellers world-wide)


VISTAA CFD-Solver


Vista Extrud Vista Marine

VISTA: A Multi-field Object Oriented CFD-package

Incompressible Navier-Stokes equation:

+ H

eat-

Pro

blem

+ A

LE

+ F

ree-

surf

ace

flow

+ T

urbu

lenc

e+

Flu

id-s

truc

ture

In

tera

ctio

n

Bloodflow-Problem1

(based on VISTA)

1 phd-thesis Runar Holdahl


Large-eddy simulation of flow around two cylinders in atandem arrangement, Re=22000,

velocity isosurface and pressure distribution

Viscous 3D flow around a cylinder, Re=265,velocity isosurface

VISTA MarineVISTA Marine


• Block structured, 8 node hexahedral FE-elements

• LES-turbulence model (Smagorinsky, Van Driest)

• Number of time steps: 5000

• Number of grid points: 770 982

• Total no. of degrees of freedom: 3 083 928

• Number of processors: 96

Parallel computers necessary for addressing this ca se!

Computational Facts


Feature List

• Incompressible flow

– Stokes/Navier-Stokes

– 2D/3D

– stationary and time dependent

– variable density

• Turbulence modeling

– LES (Smagorinsky with van Driest damping)

– RANS (k-e: High Reynolds model)

• Reference system and boundary conditions

– ALE formulation

– Moving object (FSI)

– Free surface

– Periodic boundary conditions

– General boundary conditions(Dirichlet/Neumann)

• Numerical approximation

– (Mixed) finite elements(Taylor-Hood, equal order)

– Continuous projection method(including incremental pressure formulation)

– Semi-implicit BDF time discretisation

– Parallel Krylov solver reconditionedwith two-level domain decomposition

• Software issues

– Object-oriented (c++) code based on Diffpack

– Platform independent (running on Unix/Linux)

– Parallelised with MPI

– Preprocessor: GRIDDLER

– Postprocessor: GLview, VTK, Matlab (2D)

• Usage

– NTNU/SINTEF: Free usage for education and research


VISTAA CFD-Toolbox


VISTA “Plug and Play”

(+ Diffpack)

VISTA “Plug and Play”

(+ Diffpack)

The VISTA Vision

Heat-Problem

Navier-Stokes related problem

Navier-Stokes related problem + =

owncoupled

CFDsolver

owncoupled

CFDsolver

Turbulence

Free-Surface

Fluid-Surface-Interaction


Diffpack Kernel

Diffpack Toolboxes(further extensions)

Diffpack Kernel

Diffpack Toolboxes(further extensions)

The Diffpack® Vision

[ ] in

on

u f

u g

κ−∇ ⋅ ∇ = Ω= ∂Ω

“arbitrary” PDE, ODE,

or othernumerical problem

“arbitrary” PDE, ODE,

or othernumerical problem

+ = ownsolver

ownsolver

( ), ,v tt

∂ =∂s

F s


Philosophy: Plug and play

CoupledSolver

SimCase

Problem1 Problem2

Solver1 Solver3Solver2

Data transfer by:• “get”-functions• “attach”-functions

Divide et Impera!


Example 1: Free-surface flow

FreeSurfaceSolverSimCase

InterfaceProblem ALEproblem

InterfaceSolver MeshMoverFluidSolver

FluidProblem


Vista Software - Current and Future Modules


FSIsolver

FluidSolver StructureSolver MeshMover

Example 2: FluidExample 2: Fluid--structure interactionstructure interaction


VISTAExtrud3D


Extruded Products

Building industries Automotive industry


The Extrusion Press

Profile

Die holder

Die

Container

Billet

Ram


T3

T2

P1

T1

15

3

5

6

4

1

Die

ProfileSlip

Sharp inlet

Flat Strip: Measurement points


Mathematical Formulation

• The Extrusion Problem

• Governing Equations

• Boundary Value Problems

• The Extrusion Solver


Extrusion Problem - The Domain


Governing Equations

Heat conduction:

non-Newtonian fluid:Zener-Hollomon material model


Extrusion Problem - Boundary Value Problem

Coupling throughtemperature dependentviscosity

Coupling throughadvection

Coupling throughdeformationenergy


Extrusion Problem - Boundary Value Problem (cont’d)


Extrusion Problem - Weak Formulation


Extrusion Problem - Weak Formulation (cont’d)


Extrusion Problem - Linearized Fluid Flow Equations


Extrusion Problem - Linearized Fluid Flow Equations (cont’d)


Extrusion Problem - Computer Implementation


Extrusion Problem - Model Parameter


Flat Strip: 2D-mesh

Profile

Die

Container

RamNumber of elements = 504

Billet (Aluminium)

Detail


Flat Strip: 3D-mesh

Grids do not necessarily match

Solve for• velocity u• pressure p • temperature T

Solve for temperature T


Friction

Full stick

Full slip

Visco-plastic

Slip point

Bearing Channel


Comparison with Experiments

• Extrusion of a Flat Strip

• Temperature measurements

– Aluminum

– Die

• Both 2D and 3D analyses

78.5

15

6 6

9 4 1.7

T2

3

B B

A

A

T3

T4

T1

P1


Finite Element Model

Full 3D-model Close up

Mesh

Temperature


Extrusion Problem - The Solver


Flat Strip: Temperature

t = 4.4 s t = 16.7 s


Flat Strip: Velocity

t = 11.9 s t = 16.7 s


TEMPERATURE IN T1 (°C)

460

480

500

520

540

560

580

600

620

0 20 40 60 80 100 120

rampos(mm)

T1_v09_480_stick

T1alu_v09_480_exp

y

z

T1 T4

x

Flat Strip: Temperatures in T1


TEMPERATURE IN T2 (°C)

420

430

440

450

460

470

480

490

500

0 20 40 60 80 100 120

rampos(mm)

T2_v09_480_stick

T2die_v09_480_exp

T2dT3d

x

y

z

Flat Strip: Temperatures in T2


Thank you for attention !Thank you for attention !


Feature List

• Incompressible flow

– Stokes/Navier-Stokes

– 2D/3D

– stationary and time dependent

– variable density

• Turbulence modeling

– LES (Smagorinsky with van Driest damping)

– RANS (k-e: High Reynolds model)

• Reference system and boundary conditions

– ALE formulation

– Moving object (FSI)

– Free surface

– Periodic boundary conditions

– General boundary conditions(Dirichlet/Neumann)

• Numerical approximation

– (Mixed) finite elements(Taylor-Hood, equal order)

– Continuos projection method(including incremental pressure formulation)

– Semi-implicit BDF time discretisation

– Parallel Krylov solver reconditionedwith two-level domain ecomposition

• Software issues

– Object-oriented (c++) code based on Diffpack

– Platform independent (running on Unix/Linux)

– Parallelised with MPI

– Preprocessor: GRIDDLER

– Postprocessor: GLview, VTK, Matlab (2D)

• Usage

– NTNU/SINTEF: Free usage for education and research


Structural Optimization Topology Optimization Shape Optimization Sizing- and Parameter Optimization Large Scale Optimization Multi-Disciplinary Optimization Design of Experiments Biological Growth Free Material Optimization

(Composite Design)

Structural Optimization Topology Optimization Shape Optimization Sizing- and Parameter Optimization Large Scale Optimization Multi-Disciplinary Optimization Design of Experiments Biological Growth Free Material Optimization

(Composite Design)

inuTech - Our R&D Experience


Differential Equations inuTech develops and markets the Diffpack Product

Line for the Numerical Modeling and Solution of Differential Equations

inuTech offers Consulting Services around Diffpack; we can deliver customized turn-key solutions for specialized simulation problems

Attention: Diffpack is a development environment, not a program!It allows you to generate asimulator!

Differential Equations inuTech develops and markets the Diffpack Product

Line for the Numerical Modeling and Solution of Differential Equations

inuTech offers Consulting Services around Diffpack; we can deliver customized turn-key solutions for specialized simulation problems

Attention: Diffpack is a development environment, not a program!It allows you to generate asimulator!

inuTech - Our R&D Experience


The Diffpack® Distribution

Diffpack Development Framework

Diffpack Kernel(computing/numerics)

Diffpack Toolboxes

Third-Party Pre-/Postprocessors

OpenSource Pre-/PostprocessorsDif

fpa

ckU

tilit

y

Pro

gra

ms

Books, Manpages,

Reports

Supportphone/e-mail


The Challenge

Software DevelopmentSoftware Development

Num

eric

al M

etho

dsScientific Computing

Speed-Up 1,000,000 over last 50 years

Speed-Up 1,000,000 over last 50 years

Hardw

are Power


The Diffpack® Vision (cont’d)

Structuralmechanics

Porous mediaflow

Aero-dynamics

Incompressibleflow

Other PDEapplications

Waterwaves

Electromagnetics

Heattransfer

Field

Grid

MatrixVector

I/O

Ax=b

FEM

FDM

Observation:Methodology basisindependent of applications


Diffpack® Implementation - use weak formulation

[ ] in

on

u f

u g

κ−∇ ⋅ ∇ = Ω= ∂Ω

solve on operator level ×1

, 1,..., in

on

m

j i j ij

N N d u f N d i m

u g

κ= Ω Ω

∇ ∇ Ω + = Ω = Ω

= ∂Ω

∑ ∫ ∫

Use weak formulation


Diffpack® Implementation - important member

global_menu.multipleLoop (S)

S::adm

S::define

S::scan

S::solveProblem

S::integrands

FEM::makeSystem

FEM::calcElmMatVec

FEM::numItgOverElm

S::resultReport


bAu

midNfudNNvdNNk i

m

jjijij

=

=Ω=

Ω∇⋅+Ω∇∇ ∫∑ ∫∫

Ω= ΩΩ

,...,1 , 1

Weak Formulation ( ):0=α

ConvDiff:: integrands (numerical kernel)


Apply Boundary Conditions:

1, ,0),( Γ∈= yxyxu “essential conditions”

ConvDiff :: fillEssBC (apply essential boundary Conditions)

vista: a multi -field object oriented cfd -package · 3. nafems cfd-seminar wiesbaden, 08.-09. mai...

Documents