Couple Openfoam with Any Other Solver Using Precice

Couple OpenFOAM with any other solver using preCICE

Gerasimos Chourdakis et al.

Technical University of Munich Department of Informatics Chair of Scientiﬁc Computing in Computer Science

2nd German OpenFoam User meetiNg TU Braunschweig February 21, 2018 Part II:

Agenda

Part I:

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN22 Agenda

Part I:

Part II:

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN22 How to simulate this heat exchanger?

Geometry of a shell-and-tube heat exchanger (Image by L. Cheung Yau, 2016)

Surface plot and streamlines of the two ﬂuids colored by temperature. Solid not shown. Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN23 A shell-and-tube heat exchanger with preCICE

Coupling interfaces (Image by L. Cheung Yau, 2016)

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN24 preCICE precise Code Interaction Coupling Environment

libprecice Communication adapter Data Mapping Coupling Schemes Solver A Solver B

• Free (GNU LGPL), developed at TU Munich & Univ. of Stuttgart. • Version 1.0 in November 2017 (10+ years, 3 PhD generations). • Ofﬁcial adapters for CalculiX, Code_Aster, COMSOL, Fluent, OpenFOAM, SU2

• Third-party adapters for Ateles, Alya, Carat++, FASTEST, FEAP, foam-extend, ... • API in C, C++, Fortran, Python

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN25 But why preCICE?

libprecice Ope nFOAM CHT

adapter CalculiX

in-house FSI solver

• Pure library approach → ﬂexibility • Fully parallel, peer-to-peer concept → scalable and efﬁcient communication • Sophisticated and robust quasi-Newton coupling algorithms • Multi-coupling

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN26 The roles of an adapter

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN27 Part IIa: previous approach

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN28 Duplicated development effort

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN29 Duplicated development effort

All these adapters are bound to speciﬁc solvers!

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN29 Duplicated development effort

All these adapters are bound to speciﬁc solvers! → We need an ofﬁcial, general adapter!

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN29 Example of an adapted solver (previous)

1 /* Adapter: Initialize coupling */ 22 /* solve the equations */

2 adapter.initialize(); 23 #include "rhoEqn.H"

3 24 while (pimple.loop())

4 Info<<"\nStarting time loop\n" << endl; 25 {

5 26 ...

6 while (adapter.isCouplingOngoing()) { 27 }

7 #include "readTimeControls.H" 28

8 #include "compressibleCourantNo.H" 29 /* Adapter: Write in buffers */

9 #include "setDeltaT.H" 30 adapter.writeCouplingData();

10 31

11 /* Adapter: Adjust solver time */ 32 /* Adapter: advance the coupling */

12 adapter.adjustSolverTimeStep(); 33 adapter.advance();

13 34

14 /* Adapter: Write checkpoint */ 35 /* Adapter: Read checkpoint */

15 if(adapter.isWriteCheckptRequired()) 36 if(adapter.isReadCheckptRequired())

16 adapter.writeCheckpoint(); 37 adapter.readCheckpoint();

17 38

18 runTime++; 39 if(adapter.isCouplTimeStepComplete())

19 40 runTime.write();

20 /* Adapter: Receive coupling data */ 41

21 adapter.readCouplingData(); 42 }

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 10 Before: Working and validated prototypes

Image from desertcart.ae.

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 11 Before: Working and validated prototypes

Image from desertcart.ae.

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 11 Now: A user-friendly, plug-and-play adapter

The human-like ﬁgure is a property of ikea.com.

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 12 Part IIb: a new, ofﬁcial adapter

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 13 Several advantages: • No source code changes • Load at runtime • (mostly) Solver agnostic However: • Still ready-to-run only for CHT • but...

Making this a function object

Several challenges: • No changes in the source allowed − Cannot use variables directly − Ask the objects’ registry • One adapter for all the solvers and problem types − Some parameters are not available

• Only one call to execute() at the end − We may need to reload a checkpoint at the last timestep... − Set the endTime to GREAT and exit when ready.

• Collaboration with other function objects − At the end, call any other end() methods explicitly.

• Error handling − read() degrades errors to warnings − Catch them and throw them in execute

• One adapter for all the OpenFOAM ﬂavors and versions? − E.g. boundaryField() and boundaryFieldRef() − E.g. missing adjustTimeStep() − How to distribute? Branches/Tags? Preprocessor ifdef?

• ...

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 14 However: • Still ready-to-run only for CHT • but...

Making this a function object

• Only one call to execute() at the end − We may need to reload a checkpoint at the last timestep... − Set the endTime to GREAT and exit when ready.

• Collaboration with other function objects − At the end, call any other end() methods explicitly.

• Error handling − read() degrades errors to warnings − Catch them and throw them in execute

• One adapter for all the OpenFOAM ﬂavors and versions? − E.g. boundaryField() and boundaryFieldRef() − E.g. missing adjustTimeStep() − How to distribute? Branches/Tags? Preprocessor ifdef?

• ...

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 14 Making this a function object

Several challenges: Several advantages: • No changes in the source allowed • No source code changes − Cannot use variables directly • Load at runtime − Ask the objects’ registry • (mostly) Solver agnostic • One adapter for all the solvers and problem types However: − Some parameters are not available • Still ready-to-run only for CHT • Only one call to execute() at the end • but... − We may need to reload a checkpoint at the last timestep... − Set the endTime to GREAT and exit when ready.

• Collaboration with other function objects − At the end, call any other end() methods explicitly.

• Error handling − read() degrades errors to warnings − Catch them and throw them in execute

• One adapter for all the OpenFOAM ﬂavors and versions? − E.g. boundaryField() and boundaryFieldRef() − E.g. missing adjustTimeStep() − How to distribute? Branches/Tags? Preprocessor ifdef?

• ...

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 14 An extensible adapter

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 15 OK! I want to use it!

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 16 Properties for incompressible solvers:

1 // constant/transportProperties

2 rho rho [1-300000]1;

3 Cp Cp [02-2-1000] 5000;

Properties for basic solvers:

1 // constant/transportProperties

2 k k [11-3-1000] 100;

OpenFOAM conﬁguration

1 // system/controlDict

2 functions

3 {

4 preCICE_Adapter

5 {

6 type preciceAdapterFunctionObject;

7 libs ("libpreciceAdapterFunctionObject.so");

8 }

9 }

Set the appropriate boundary condition types:

1 // 0/T

2 interface

3 {

4 type fixedValue;

5 value uniform 300;

6 }

8 // other types: fixedGradient, mixed

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 17 OpenFOAM conﬁguration

1 // system/controlDict

2 functions

3 {

4 preCICE_Adapter

5 {

6 type preciceAdapterFunctionObject;

7 libs ("libpreciceAdapterFunctionObject.so");

8 }

9 }

Set the appropriate boundary condition types: Properties for incompressible solvers:

1 // 0/T 1 // constant/transportProperties

2 interface 2 rho rho [1-300000]1;

3 { 3 Cp Cp [02-2-1000] 5000;

4 type fixedValue; Properties for basic solvers: 5 value uniform 300;

6 } 1 // constant/transportProperties 7 2 k k [11-3-1000] 100; 8 // other types: fixedGradient, mixed

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 17 preCICE & adapter conﬁguration

libprecice adapter

Solver A Solver B

YAML YAML XML

Adapter A Config Adapter B Config preCICE Config

To run the simulation, just execute the solvers as usual.

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 18 Tutorials

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 19 Example: Biomedical applications

• FSI simulation of an aortic bloodﬂow • Joint work with the Barcelona Supercomputing Center

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 20 Example: Multi-ﬂuid coupling

Linearized Euler Equations

• Besides FSI, many other possible Euler applications of preCICE Equations • Simulation of a subsonic jet w w o o • Navier-Stokes f t Explicit, parallel coupling between three ﬂuid f u n

I Equations solvers O • Joint work with the University of Siegen Euler Equations

Linearized Euler Equations

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 21 Does it work with “chocolate” OpenFOAM?

Known to work with: The OpenFOAM Foundation: 4.0 – dev ESI - OpenCFD: v1706

Currently does not work with: The OpenFOAM Foundation: ≤ 3.0 ESI - OpenCFD: ≤ v1606+ foam-extend: any version

Coming soon: • Support for older versions • Code improvements and tests Contribute on GitHub! • Fluid-Structure Interaction Module

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 22 Questions?

Website: precice.org Mailing list: precice.org/resources Source/Wiki: github.com/precice My e-mail: [email protected]

Homework: • Follow a tutorial • Join our mailing list • Star on GitHub • Send us feedback • Ask me for stickers

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 23 Questions?

Website: precice.org Mailing list: precice.org/resources Source/Wiki: github.com/precice My e-mail: [email protected]

Homework: • Follow a tutorial • Join our mailing list • Star on GitHub • Send us feedback • Ask me for stickers

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 23 Additional slide: Time step sizes

Time step sizes and checkpointing

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 24 Additional slide: Function Objects

Callbacks in OpenFOAM function objects

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 25 Additional slide: The CHT Module

The Conjugate Heat Transfer module

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 26 Additional slide: preCICE scaling

Strong scaling of a coupled simulation with two Ateles participants and 5.7 · 107dofs

Gerasimos Chourdakis (TUM) | Couple OpenFOAM with any other solver using preCICE | Feb 21, 2018 | GOFUN2 27