From c44e4d171936c95a4dce3a365a6ed0c2ea99bef1 Mon Sep 17 00:00:00 2001
From: David Schneider <david.schneider@ipvs.uni-stuttgart.de>
Date: Thu, 22 Jan 2026 12:39:46 +0100
Subject: [PATCH 1/3] Add initial setup

---
 channel-transport-particles/clean-tutorial.sh |   1 +
 .../fluid-nutils/clean.sh                     |   6 +
 .../fluid-nutils/fluid.py                     | 111 +++++++++++++
 .../fluid-nutils/requirements.txt             |   5 +
 .../fluid-nutils/run.sh                       |  16 ++
 .../fluid-openfoam/0/U                        |  39 +++++
 .../fluid-openfoam/0/p                        |  45 ++++++
 .../fluid-openfoam/clean.sh                   |   6 +
 .../constant/transportProperties              |  11 ++
 .../constant/turbulenceProperties             |   9 ++
 .../fluid-openfoam/run.sh                     |  12 ++
 .../fluid-openfoam/system/blockMeshDict       | 146 ++++++++++++++++++
 .../fluid-openfoam/system/controlDict         |  45 ++++++
 .../fluid-openfoam/system/decomposeParDict    |  16 ++
 .../fluid-openfoam/system/fvSchemes           |  39 +++++
 .../fluid-openfoam/system/fvSolution          |  74 +++++++++
 .../fluid-openfoam/system/preciceDict         |  32 ++++
 .../particles-mercurydpm/.keepme              |   0
 .../precice-config.xml                        |  44 ++++++
 19 files changed, 657 insertions(+)
 create mode 120000 channel-transport-particles/clean-tutorial.sh
 create mode 100755 channel-transport-particles/fluid-nutils/clean.sh
 create mode 100644 channel-transport-particles/fluid-nutils/fluid.py
 create mode 100644 channel-transport-particles/fluid-nutils/requirements.txt
 create mode 100755 channel-transport-particles/fluid-nutils/run.sh
 create mode 100644 channel-transport-particles/fluid-openfoam/0/U
 create mode 100644 channel-transport-particles/fluid-openfoam/0/p
 create mode 100755 channel-transport-particles/fluid-openfoam/clean.sh
 create mode 100644 channel-transport-particles/fluid-openfoam/constant/transportProperties
 create mode 100644 channel-transport-particles/fluid-openfoam/constant/turbulenceProperties
 create mode 100755 channel-transport-particles/fluid-openfoam/run.sh
 create mode 100644 channel-transport-particles/fluid-openfoam/system/blockMeshDict
 create mode 100644 channel-transport-particles/fluid-openfoam/system/controlDict
 create mode 100644 channel-transport-particles/fluid-openfoam/system/decomposeParDict
 create mode 100644 channel-transport-particles/fluid-openfoam/system/fvSchemes
 create mode 100644 channel-transport-particles/fluid-openfoam/system/fvSolution
 create mode 100644 channel-transport-particles/fluid-openfoam/system/preciceDict
 create mode 100644 channel-transport-particles/particles-mercurydpm/.keepme
 create mode 100644 channel-transport-particles/precice-config.xml

diff --git a/channel-transport-particles/clean-tutorial.sh b/channel-transport-particles/clean-tutorial.sh
new file mode 120000
index 000000000..4713f5092
--- /dev/null
+++ b/channel-transport-particles/clean-tutorial.sh
@@ -0,0 +1 @@
+../tools/clean-tutorial-base.sh
\ No newline at end of file
diff --git a/channel-transport-particles/fluid-nutils/clean.sh b/channel-transport-particles/fluid-nutils/clean.sh
new file mode 100755
index 000000000..0d1c2d23d
--- /dev/null
+++ b/channel-transport-particles/fluid-nutils/clean.sh
@@ -0,0 +1,6 @@
+#!/usr/bin/env sh
+set -e -u
+
+. ../../tools/cleaning-tools.sh
+
+clean_nutils .
diff --git a/channel-transport-particles/fluid-nutils/fluid.py b/channel-transport-particles/fluid-nutils/fluid.py
new file mode 100644
index 000000000..aa91605df
--- /dev/null
+++ b/channel-transport-particles/fluid-nutils/fluid.py
@@ -0,0 +1,111 @@
+#! /usr/bin/env python3
+
+#
+# Incompressible NSE solved within a channel geometry with parabolic inflow profile and an obstacle attached to the bottom towards the middle of the domain. The fluid field is initialized with a Stokes solution. The resulting velocity field is written to preCICE on the complete volume.
+#
+
+from nutils import function, mesh, cli, solver, export
+import treelog as log
+import numpy as np
+import precice
+from mpi4py import MPI
+
+
+def main():
+
+    print("Running Nutils")
+
+    # define the Nutils mesh
+    nx = 48
+    ny = 16
+    step_start = nx // 3
+    step_end = nx // 2
+    step_hight = ny // 2
+
+    grid = np.linspace(0, 6, nx + 1), np.linspace(0, 2, ny + 1)
+    domain, geom = mesh.rectilinear(grid)
+    domain = domain.withboundary(inflow="left", outflow="right", wall="top,bottom") - domain[
+        step_start:step_end, :step_hight
+    ].withboundary(wall="left,top,right")
+
+    # cloud of Gauss points
+    gauss = domain.sample("gauss", degree=4)
+
+    # Nutils namespace
+    ns = function.Namespace()
+    ns.x = geom
+
+    ns.ubasis = domain.basis("std", degree=2).vector(2)
+    ns.pbasis = domain.basis("std", degree=1)
+    ns.u_i = "ubasis_ni ?u_n"  # solution
+    ns.p = "pbasis_n ?p_n"  # solution
+    ns.dudt_i = "ubasis_ni (?u_n - ?u0_n) / ?dt"  # time derivative
+    ns.μ = 0.5  # viscosity
+    ns.σ_ij = "μ (u_i,j + u_j,i) - p δ_ij"
+    ns.uin = "10 x_1 (2 - x_1)"  # inflow profile
+
+    # define the weak form, Stokes problem
+    ures = gauss.integral("ubasis_ni,j σ_ij d:x" @ ns)
+    pres = gauss.integral("pbasis_n u_k,k d:x" @ ns)
+
+    # define Dirichlet boundary condition
+    sqr = domain.boundary["inflow"].integral("(u_0 - uin)^2 d:x" @ ns, degree=2)
+    sqr += domain.boundary["inflow,outflow"].integral("u_1^2 d:x" @ ns, degree=2)
+    sqr += domain.boundary["wall"].integral("u_k u_k d:x" @ ns, degree=2)
+    cons = solver.optimize(["u"], sqr, droptol=1e-15)
+
+    # preCICE setup
+    participant = precice.Participant("Fluid", "../precice-config.xml", 0, 1)
+
+    # define coupling mesh
+    mesh_name = "Fluid-Mesh"
+    vertices = gauss.eval(ns.x)
+    vertex_ids = participant.set_mesh_vertices(mesh_name, vertices)
+
+    # coupling data
+    data_name = "Velocity"
+
+    participant.initialize()
+
+    timestep = 0
+    solver_dt = 0.005
+    precice_dt = participant.get_max_time_step_size()
+    dt = min(precice_dt, solver_dt)
+
+    state = solver.solve_linear(("u", "p"), (ures, pres), constrain=cons)  # initial condition
+
+    # add convective term and time derivative for Navier-Stokes
+    ures += gauss.integral("ubasis_ni (dudt_i + μ (u_i u_j)_,j) d:x" @ ns)
+
+    while participant.is_coupling_ongoing():
+
+        if timestep % 1 == 0:  # visualize
+            bezier = domain.sample("bezier", 2)
+            x, u, p = bezier.eval(["x_i", "u_i", "p"] @ ns, **state)
+            with log.add(log.DataLog()):
+                export.vtk("Fluid_" + str(timestep), bezier.tri, x, u=u, p=p)
+
+        precice_dt = participant.get_max_time_step_size()
+
+        # potentially adjust non-matching timestep sizes
+        dt = min(solver_dt, precice_dt)
+
+        # solve Nutils timestep
+        state["u0"] = state["u"]
+        state["dt"] = dt
+        state = solver.newton(("u", "p"), (ures, pres), constrain=cons, arguments=state).solve(1e-10)
+
+        velocity_values = gauss.eval(ns.u, **state)
+        participant.write_data(mesh_name, data_name, vertex_ids, velocity_values)
+
+        # do the coupling
+        participant.advance(dt)
+
+        # advance variables
+        timestep += 1
+
+    participant.finalize()
+
+
+if __name__ == "__main__":
+    cli.run(main)
diff --git a/channel-transport-particles/fluid-nutils/requirements.txt b/channel-transport-particles/fluid-nutils/requirements.txt
new file mode 100644
index 000000000..56c3d4a92
--- /dev/null
+++ b/channel-transport-particles/fluid-nutils/requirements.txt
@@ -0,0 +1,5 @@
+setuptools # required by nutils
+nutils==7
+numpy >1, <2
+pyprecice~=3.0
+setuptools
diff --git a/channel-transport-particles/fluid-nutils/run.sh b/channel-transport-particles/fluid-nutils/run.sh
new file mode 100755
index 000000000..641f4f465
--- /dev/null
+++ b/channel-transport-particles/fluid-nutils/run.sh
@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+set -e -u
+
+. ../../tools/log.sh
+exec > >(tee --append "$LOGFILE") 2>&1
+
+if [ ! -v PRECICE_TUTORIALS_NO_VENV ]
+then
+    python3 -m venv .venv
+    . .venv/bin/activate
+    pip install -r requirements.txt && pip freeze > pip-installed-packages.log
+fi
+
+python3 fluid.py
+
+close_log
diff --git a/channel-transport-particles/fluid-openfoam/0/U b/channel-transport-particles/fluid-openfoam/0/U
new file mode 100644
index 000000000..2cf022003
--- /dev/null
+++ b/channel-transport-particles/fluid-openfoam/0/U
@@ -0,0 +1,39 @@
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       volVectorField;
+    object      U;
+}
+
+dimensions      [0 1 -1 0 0 0 0];
+internalField   uniform (10 0 0);
+
+boundaryField
+{
+    inlet
+    {
+        type            fixedValue;
+        value           $internalField;
+    }
+    outlet
+    {
+        type            zeroGradient;
+    }
+    obstacle
+    {
+        type            noSlip;
+    }
+    upperWall
+    {
+        type            noSlip;
+    }
+    lowerWall
+    {
+        type            noSlip;
+    }
+    frontAndBack
+    {
+        type            empty;
+    }
+}
diff --git a/channel-transport-particles/fluid-openfoam/0/p b/channel-transport-particles/fluid-openfoam/0/p
new file mode 100644
index 000000000..5252ec67a
--- /dev/null
+++ b/channel-transport-particles/fluid-openfoam/0/p
@@ -0,0 +1,45 @@
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       volScalarField;
+    object      p;
+}
+
+dimensions      [0 2 -2 0 0 0 0];
+
+internalField   uniform 0;
+
+boundaryField
+{
+    inlet
+    {
+        type            zeroGradient;
+    }
+
+    outlet
+    {
+        type            fixedValue;
+        value           uniform 0;
+    }
+
+    obstacle
+    {
+        type            zeroGradient;
+    }
+    
+    upperWall
+    {
+        type            zeroGradient;
+    }
+
+    lowerWall
+    {
+        type            zeroGradient;
+    }
+
+    frontAndBack
+    {
+        type            empty;
+    }
+}
\ No newline at end of file
diff --git a/channel-transport-particles/fluid-openfoam/clean.sh b/channel-transport-particles/fluid-openfoam/clean.sh
new file mode 100755
index 000000000..b64fc5101
--- /dev/null
+++ b/channel-transport-particles/fluid-openfoam/clean.sh
@@ -0,0 +1,6 @@
+#!/usr/bin/env sh
+set -e -u
+
+. ../../tools/cleaning-tools.sh
+
+clean_openfoam .
diff --git a/channel-transport-particles/fluid-openfoam/constant/transportProperties b/channel-transport-particles/fluid-openfoam/constant/transportProperties
new file mode 100644
index 000000000..5383adaad
--- /dev/null
+++ b/channel-transport-particles/fluid-openfoam/constant/transportProperties
@@ -0,0 +1,11 @@
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    object      transportProperties;
+}
+
+transportModel  Newtonian;
+
+nu              nu [ 0 2 -1 0 0 0 0 ] 1;
diff --git a/channel-transport-particles/fluid-openfoam/constant/turbulenceProperties b/channel-transport-particles/fluid-openfoam/constant/turbulenceProperties
new file mode 100644
index 000000000..592f6d52d
--- /dev/null
+++ b/channel-transport-particles/fluid-openfoam/constant/turbulenceProperties
@@ -0,0 +1,9 @@
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    object      turbulenceProperties;
+}
+
+simulationType laminar;
diff --git a/channel-transport-particles/fluid-openfoam/run.sh b/channel-transport-particles/fluid-openfoam/run.sh
new file mode 100755
index 000000000..8f55fbfa5
--- /dev/null
+++ b/channel-transport-particles/fluid-openfoam/run.sh
@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+set -e -u
+
+. ../../tools/log.sh
+exec > >(tee --append "$LOGFILE") 2>&1
+
+blockMesh
+
+../../tools/run-openfoam.sh "$@"
+. ../../tools/openfoam-remove-empty-dirs.sh && openfoam_remove_empty_dirs
+
+close_log
diff --git a/channel-transport-particles/fluid-openfoam/system/blockMeshDict b/channel-transport-particles/fluid-openfoam/system/blockMeshDict
new file mode 100644
index 000000000..bdb4fe67b
--- /dev/null
+++ b/channel-transport-particles/fluid-openfoam/system/blockMeshDict
@@ -0,0 +1,146 @@
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    object      blockMeshDict;
+}
+
+x0 0.;
+x1 2.;
+x2 3.;
+x3 6.;
+
+y0 0.;
+y1 1.;
+y2 2.;
+
+z0 0;
+z1 1;
+
+vertices
+(
+    ($x0 $y0 $z0 )         // 0
+    ($x1 $y0 $z0 )         // 1
+    ($x2 $y0 $z0 )         // 2
+    ($x3 $y0 $z0 )         // 3
+    ($x0 $y1 $z0 )         // 4
+    ($x1 $y1 $z0 )         // 5
+    ($x2 $y1 $z0 )         // 6
+    ($x3 $y1 $z0 )         // 7
+    ($x0 $y2 $z0 )         // 8
+    ($x1 $y2 $z0 )         // 9
+    ($x2 $y2 $z0 )         // 10
+    ($x3 $y2 $z0 )         // 11
+
+    ($x0 $y0 $z1 )         // 12
+    ($x1 $y0 $z1 )         // 13
+    ($x2 $y0 $z1 )         // 14
+    ($x3 $y0 $z1 )         // 15
+    ($x0 $y1 $z1 )         // 16
+    ($x1 $y1 $z1 )         // 17
+    ($x2 $y1 $z1 )         // 18
+    ($x3 $y1 $z1 )         // 19
+    ($x0 $y2 $z1 )         // 20
+    ($x1 $y2 $z1 )         // 21
+    ($x2 $y2 $z1 )         // 22
+    ($x3 $y2 $z1 )         // 23
+);
+
+
+// Grading
+h1 16;
+h2 8;
+h3 24;
+v1 8;
+
+blocks
+(
+    hex (   0   1   5   4   12  13  17  16  )
+    ($h1 $v1 1 )
+    simpleGrading (1 1 1)
+
+    hex (   2   3   7   6   14  15  19  18  )
+    ($h3 $v1 1)
+    simpleGrading (1 1 1)
+
+    hex (   4   5   9   8   16  17  21  20  )
+    ($h1 $v1 1)
+    simpleGrading (1 1 1)
+
+    hex (   5   6   10  9   17  18  22  21  )
+    ($h2 $v1 1)
+    simpleGrading (1 1 1)
+
+    hex (   6   7   11  10  18  19  23  22  )
+    ($h3 $v1 1 )
+    simpleGrading (1 1 1)
+);
+
+boundary
+(
+    inlet
+    {
+        type patch;
+        faces
+        (
+            (  0   4   16  12  )
+            (  4   8   20  16  )
+        );
+    }
+    outlet
+    {
+        type patch;
+        faces
+        (
+            (   3   7   19  15  )
+            (   7   11  23  19  )
+        );
+    }
+    obstacle
+    {
+        type wall;
+        faces
+        (
+            (   1   5   17  13  )
+            (   5   6   18  17  )
+            (   6   2   14  18  )
+        );
+    }
+    upperWall
+    {
+        type wall;
+        faces
+        (
+            (   8   9   21  20  )
+            (   9   10  22  21  )
+            (   10  11  23  22  )
+        );
+    }
+    lowerWall
+    {
+        type wall;
+        faces
+        (
+            (   0   1   13  12  )
+            (   2   3   15  14  )
+        );
+    }
+    frontAndBack
+    {
+        type empty;
+        faces
+        (
+            (   0   1   5   4   )
+            (   2   3   7   6   )
+            (   4   5   9   8   )
+            (   5   6   10  9   )
+            (   6   7   11  10  )
+            (   12  13  17  16  )
+            (   14  15  19  18  )
+            (   16  17  21  20  )
+            (   17  18  22  21  )
+            (   18  19  23  22  )
+        );
+    }
+);
\ No newline at end of file
diff --git a/channel-transport-particles/fluid-openfoam/system/controlDict b/channel-transport-particles/fluid-openfoam/system/controlDict
new file mode 100644
index 000000000..55c798b99
--- /dev/null
+++ b/channel-transport-particles/fluid-openfoam/system/controlDict
@@ -0,0 +1,45 @@
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    object      controlDict;
+}
+
+application     pimpleFoam;
+
+startFrom       startTime;
+
+startTime       0;
+
+stopAt          endTime;
+
+endTime         1.0;
+
+deltaT          0.005;
+
+writeControl    adjustableRunTime;
+
+writeInterval   0.005;
+
+purgeWrite      0;
+
+writeFormat     ascii;
+
+writePrecision  6;
+
+writeCompression off;
+
+timeFormat      general;
+
+timePrecision   6;
+
+libs ("libpreciceAdapterFunctionObject.so");
+functions
+{
+    preCICE_Adapter
+    {
+        type preciceAdapterFunctionObject;
+        errors strict; // Available since OpenFOAM v2012
+    }
+}
diff --git a/channel-transport-particles/fluid-openfoam/system/decomposeParDict b/channel-transport-particles/fluid-openfoam/system/decomposeParDict
new file mode 100644
index 000000000..f9eae003a
--- /dev/null
+++ b/channel-transport-particles/fluid-openfoam/system/decomposeParDict
@@ -0,0 +1,16 @@
+FoamFile {
+    version     2.0;
+    class       dictionary;
+    object      decomposeParDict;
+    format      ascii;
+}
+
+numberOfSubdomains 4;
+
+method          simple;
+
+simpleCoeffs
+{
+    n               (2 2 1);
+    delta           0.001;
+}
\ No newline at end of file
diff --git a/channel-transport-particles/fluid-openfoam/system/fvSchemes b/channel-transport-particles/fluid-openfoam/system/fvSchemes
new file mode 100644
index 000000000..80c096192
--- /dev/null
+++ b/channel-transport-particles/fluid-openfoam/system/fvSchemes
@@ -0,0 +1,39 @@
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    object      fvSchemes;
+}
+
+ddtSchemes
+{
+    default         Euler;
+}
+
+gradSchemes
+{
+    default         Gauss linear;
+}
+
+divSchemes
+{
+    default         none;
+    div(phi,U)      bounded Gauss upwind;
+    div((nuEff*dev2(T(grad(U))))) Gauss linear;
+}
+
+laplacianSchemes
+{
+    default         Gauss linear corrected;
+}
+
+interpolationSchemes
+{
+    default         linear;
+}
+
+snGradSchemes
+{
+    default         corrected;
+}
diff --git a/channel-transport-particles/fluid-openfoam/system/fvSolution b/channel-transport-particles/fluid-openfoam/system/fvSolution
new file mode 100644
index 000000000..d8045408b
--- /dev/null
+++ b/channel-transport-particles/fluid-openfoam/system/fvSolution
@@ -0,0 +1,74 @@
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    location    "system";
+    object      fvSolution;
+}
+
+solvers
+{
+
+    p
+    {
+            
+    solver           PCG;
+    preconditioner   DIC;
+    tolerance        1e-8;
+    relTol 	         1e-3;
+    }
+
+    pFinal
+    {
+        $p;
+        relTol          0;
+    }
+
+    pcorr
+    {
+        $p;
+    }
+
+    pcorrFinal
+    {
+        $pcorr;
+        relTol          0;
+    }
+
+    Phi
+    {
+        $p;
+    }
+
+    "(U|cellDisplacement)"
+    {
+        solver          smoothSolver;
+        smoother        symGaussSeidel;
+        tolerance       1e-6;
+        relTol          1e-4;
+        minIter         2;
+    }
+
+    "(U|cellDisplacement)Final"
+    {
+        $U;
+        relTol          0;
+    }
+}
+
+PIMPLE
+{
+    nCorrectors 4;
+    nNonOrthogonalCorrectors 1;
+    consistent  true;
+    correctPhi  true;
+    momentumPredictor true; 
+    nOuterCorrectors	1;
+}
+
+
+potentialFlow
+{
+    nNonOrthogonalCorrectors 10;
+}
diff --git a/channel-transport-particles/fluid-openfoam/system/preciceDict b/channel-transport-particles/fluid-openfoam/system/preciceDict
new file mode 100644
index 000000000..7368a7a56
--- /dev/null
+++ b/channel-transport-particles/fluid-openfoam/system/preciceDict
@@ -0,0 +1,32 @@
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    object      preciceDict;
+}
+
+preciceConfig "../precice-config.xml";
+
+participant Fluid;
+
+modules (FF);
+
+interfaces
+{
+  Interface1
+  {
+    mesh              Fluid-Mesh;
+    patches           ();
+    locations         volumeCenters;
+    
+    readData
+    (
+    );
+
+    writeData
+    (
+        Velocity
+    );
+  };
+};
\ No newline at end of file
diff --git a/channel-transport-particles/particles-mercurydpm/.keepme b/channel-transport-particles/particles-mercurydpm/.keepme
new file mode 100644
index 000000000..e69de29bb
diff --git a/channel-transport-particles/precice-config.xml b/channel-transport-particles/precice-config.xml
new file mode 100644
index 000000000..0d0d77cb8
--- /dev/null
+++ b/channel-transport-particles/precice-config.xml
@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<precice-configuration experimental="True" allow-remeshing="True">
+  <log>
+    <sink
+      filter="%Severity% > debug and %Rank% = 0"
+      format="---[precice] %ColorizedSeverity% %Message%"
+      enabled="true" />
+  </log>
+
+  <profiling mode="fundamental" synchronize="false" />
+
+  <data:vector name="Velocity" />
+
+  <mesh name="Fluid-Mesh" dimensions="2">
+    <use-data name="Velocity" />
+  </mesh>
+
+  <mesh name="Transport-Mesh" dimensions="2">
+    <use-data name="Velocity" />
+  </mesh>
+
+  <participant name="Fluid">
+    <provide-mesh name="Fluid-Mesh" />
+    <receive-mesh name="Transport-Mesh" from="Transport" />
+    <write-data name="Velocity" mesh="Fluid-Mesh" />
+    <mapping:rbf direction="write" from="Fluid-Mesh" to="Transport-Mesh" constraint="consistent">
+      <basis-function:compact-tps-c2 support-radius="0.4" />
+    </mapping:rbf>
+  </participant>
+
+  <participant name="Transport">
+    <provide-mesh name="Transport-Mesh" />
+    <read-data name="Velocity" mesh="Transport-Mesh" />
+  </participant>
+
+  <m2n:sockets acceptor="Fluid" connector="Transport" exchange-directory=".." />
+
+  <coupling-scheme:parallel-explicit>
+    <time-window-size value="0.005" />
+    <max-time value="1.0" />
+    <participants first="Fluid" second="Transport" />
+    <exchange data="Velocity" mesh="Transport-Mesh" from="Fluid" to="Transport" />
+  </coupling-scheme:parallel-explicit>
+</precice-configuration>

From a0bbd04b24ec1ff55bd8e2bb2097db381fe89d8a Mon Sep 17 00:00:00 2001
From: David Schneider <david.schneider@ipvs.uni-stuttgart.de>
Date: Thu, 22 Jan 2026 18:43:50 +0100
Subject: [PATCH 2/3] Configure the case properly

---
 .../precice-config.xml                        | 31 +++++++++----------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/channel-transport-particles/precice-config.xml b/channel-transport-particles/precice-config.xml
index 0d0d77cb8..01af32b7a 100644
--- a/channel-transport-particles/precice-config.xml
+++ b/channel-transport-particles/precice-config.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<precice-configuration experimental="True" allow-remeshing="True">
+<precice-configuration experimental="true">
   <log>
     <sink
       filter="%Severity% > debug and %Rank% = 0"
@@ -15,30 +15,29 @@
     <use-data name="Velocity" />
   </mesh>
 
-  <mesh name="Transport-Mesh" dimensions="2">
-    <use-data name="Velocity" />
-  </mesh>
-
   <participant name="Fluid">
     <provide-mesh name="Fluid-Mesh" />
-    <receive-mesh name="Transport-Mesh" from="Transport" />
     <write-data name="Velocity" mesh="Fluid-Mesh" />
-    <mapping:rbf direction="write" from="Fluid-Mesh" to="Transport-Mesh" constraint="consistent">
-      <basis-function:compact-tps-c2 support-radius="0.4" />
-    </mapping:rbf>
   </participant>
 
-  <participant name="Transport">
-    <provide-mesh name="Transport-Mesh" />
-    <read-data name="Velocity" mesh="Transport-Mesh" />
+  <participant name="Particles">
+    <receive-mesh name="Fluid-Mesh" from="Fluid" api-access="true" />
+    <read-data name="Velocity" mesh="Fluid-Mesh" />
+    <mapping:rbf-pum-direct
+      direction="read"
+      from="Fluid-Mesh"
+      constraint="consistent"
+      vertices-per-cluster="30">
+      <basis-function:compact-polynomial-c4 support-radius="1.5" />
+    </mapping:rbf-pum-direct>
   </participant>
 
-  <m2n:sockets acceptor="Fluid" connector="Transport" exchange-directory=".." />
+  <m2n:sockets acceptor="Fluid" connector="Particles" exchange-directory=".." />
 
   <coupling-scheme:parallel-explicit>
     <time-window-size value="0.005" />
-    <max-time value="1.0" />
-    <participants first="Fluid" second="Transport" />
-    <exchange data="Velocity" mesh="Transport-Mesh" from="Fluid" to="Transport" />
+    <max-time value="0.25" />
+    <participants first="Fluid" second="Particles" />
+    <exchange data="Velocity" mesh="Fluid-Mesh" from="Fluid" to="Particles" />
   </coupling-scheme:parallel-explicit>
 </precice-configuration>

From f4ae5cef75eca027c64bc1f10351cfd14dbba1b3 Mon Sep 17 00:00:00 2001
From: David Schneider <david.schneider@ipvs.uni-stuttgart.de>
Date: Mon, 26 Jan 2026 18:23:32 +0100
Subject: [PATCH 3/3] Add preliminary README

---
 channel-transport-particles/README.md | 55 +++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 channel-transport-particles/README.md

diff --git a/channel-transport-particles/README.md b/channel-transport-particles/README.md
new file mode 100644
index 000000000..1de7d35cc
--- /dev/null
+++ b/channel-transport-particles/README.md
@@ -0,0 +1,55 @@
+---
+title: Channel transport with particles
+permalink: tutorials-channel-transport-particles.html
+keywords: volume coupling, particles, OpenFOAM, MercuryDPM, transport, just-in-time mapping
+summary: A CFD problem is coupled to a particles in a uni-directional way for particles tracing.
+---
+
+{% note %}
+Get the [case files of this tutorial](https://github.com/precice/tutorials/tree/master/channel-transport-particles). Read how in the [tutorials introduction](https://precice.org/tutorials.html).
+{% endnote %}
+
+## Setup
+
+We model a two-dimensional incompressible fluid flowing through a channel with an obstacle. The fluid problem is coupled to a particle participant for particle tracing. Similar to the transport problem (see the [channel-transport tutorial](tutorials-channel-transport.html)), particles are arranged in a circular blob close to the inflow.
+
+## Configuration
+
+preCICE configuration (image generated using the [precice-config-visualizer](https://precice.org/tooling-config-visualization.html)):
+
+![preCICE configuration visualization](images/tutorials-channel-transport-precice-config.png
+)
+
+## Available solvers
+
+Fluid participant:
+
+* Nutils. For more information, have a look at the [Nutils adapter documentation](https://precice.org/adapter-nutils.html). This Nutils solver requires at least Nutils v7.0.
+
+* OpenFOAM (pimpleFoam). For more information, have a look at the [OpenFOAM adapter documentation](https://precice.org/adapter-openfoam-overview.html).
+
+Particle participant:
+
+* MercuryDPM
+
+## Running the simulation
+
+For the fluid solver, use Nutils for ease of installation and OpenFOAM for speed.
+
+Open two separate terminals and start one fluid and one transport participant by calling the respective run scripts `run.sh` located in each of the participants' directory. For example:
+
+```bash
+cd fluid-nutils
+./run.sh
+```
+
+and either the non-adaptive mesh transport solver
+
+```bash
+cd particles-mercurydpm
+./run.sh
+```
+
+## Post-processing
+
+All solvers generate `vtk` files which can be visualized using, e.g., ParaView.