Import Sample Surface

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Import Sample Surface#

This snippet demonstrates how to import external surface mesh files into a Flow360 project and use them as output surfaces to extract flow field data and compute surface integrals.

import flow360 as fl

# Load an existing project that already has a volume mesh
project = fl.Project.from_cloud("YOUR_PROJECT_ID")
volume_mesh = project.volume_mesh

# Import one or more surface mesh files (STL, CGNS, or UGRID)
surface_a = project.import_surface_mesh("surface_a.stl", name="surface_a")
surface_b = project.import_surface_mesh("surface_b.stl", name="surface_b")

with fl.create_draft(
    new_run_from=volume_mesh,
    imported_surfaces=[surface_a, surface_b],
) as draft:
    with fl.SI_unit_system:
        # Define a user variable to compute local mass flux at each surface node
        mass_flux = fl.UserVariable(
            name="MassFlux",
            value=fl.solution.density
            * fl.math.dot(fl.solution.velocity, fl.solution.node_unit_normal),
        )

        params = fl.SimulationParams(
            operating_condition=fl.AerospaceCondition(velocity_magnitude=10*fl.u.m/fl.u.s),
            models=[...],
            time_stepping=fl.Steady(),
            outputs=[
                # Extract flow field quantities on the imported surfaces
                fl.SurfaceOutput(
                    output_fields=[fl.solution.velocity, fl.solution.Cp],
                    surfaces=[
                        draft.imported_surfaces["surface_a"],
                        draft.imported_surfaces["surface_b"],
                    ],
                ),
                # Integrate the mass flux over each imported surface
                fl.SurfaceIntegralOutput(
                    name="MassFluxIntegral",
                    output_fields=[mass_flux],
                    surfaces=[
                        draft.imported_surfaces["surface_a"],
                        draft.imported_surfaces["surface_b"],
                    ],
                ),
            ],
        )
    project.run_case(params, name="imported_surface_outputs")

Notes#

  • project.import_surface_mesh(filename, name=) uploads the surface file to the cloud and registers it with the project. The name argument is the key used to reference the surface inside the draft context.

  • Imported surfaces must be passed to fl.create_draft() via the imported_surfaces argument before they can be referenced.

  • Inside the draft context, use draft.imported_surfaces["name"] to retrieve a reference to an imported surface for use in any output type.

  • Supported surface file formats are STL, CGNS, and UGRID.

  • For a complete example that includes boundary conditions and user-defined surface integral variables, see the Flow360 GitHub example.

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