Learn OpenFOAM CFD (Level 3)

Study mixing layer growth, entrainment, and reattachment length through open-source CAD-to-post-processing: simulate single-phase and multiphase turbulent flow over a backward-facing step with FreeCAD, Salome, OpenFOAM, and Paraview.

Learn to create a 2D CAD sketch in FreeCAD 0.21.2 using the part design workbench, with polyline construction, dimensional constraints, and exporting a step file for Salomé mesh generation.

Import a step CAD into Salome, define inlet, outlet, and wall boundaries, create a 2d mesh with Net Gen, then extrude to 3d for Openfoam.

Export the mesh, set up the OpenFOAM case by importing the mesh and configuring boundaries, material, turbulence, and solver settings, then run the simple form command and repeat for multiphase.

Import a 2D mesh into OpenFOAM by navigating the Ubuntu terminal, then set boundary types in the constant/polymesh boundary file and visualize in Paraview.

Set transport properties with kinematic viscosity 1.4e-5, apply the k-epsilon turbulence model, and define boundary conditions in the zero folder (zero gradient, no-slip, default faces).

Compute k and epsilon in OpenFOAM using turbulent intensity and reference speed, with mu and L; derive k = 0.375 and epsilon = C_mu^0.75 k^1.5 / L.

Configure k inlet 0.375. Then apply k q r wall function type for walls and epsilon, rename to default faces, compute T from k and epsilon, outlet zero gradient, save.

Configure Openfoam with DDT and Laplacian schemes for steady state, set tolerances and relaxation factors, adjust residuals, and update control dict to run 2000 iterations with a 50 write interval.

Launch a single phase OpenFOAM simulation from the terminal, monitor convergence and iterations, then post-process in Paraview with velocity contours, vectors, and streamlines to identify recirculation zones.

Postprocess Paraview results from a single-phase simulation by importing the case, displaying velocity magnitude contours and vectors, and visualizing streamlines.

Set up a multiphase OpenFOAM simulation using a vof solver with water and air, using coarser Salome mesh, create two_multiphase, copy files, and add alpha.water, p_rgh, gravity, and system controls.

Create a 2D hexahedral mesh in Salome from CAD, then extrude to a 3D mesh for multiphase OpenFOAM. Export as unv, import, and set inlet, outlet, and boundary conditions.

Set gravity in the negative y direction, apply k-epsilon turbulence, define water and air properties in constant, and configure fixed inlet velocity 10 and atmospheric upper-wall boundaries in zero.

Learn to set up a multiphase OpenFOAM simulation by configuring interFoam and schemes, enabling automatic time-step control to keep the Courant number near 0.95.

Postprocess multiphase OpenFOAM simulations in ParaView by loading cases, animating velocity and alpha water fields, and identifying steady-state flow and recirculation after the step.