Pre-processing for immersed boundary conditions


Cassiopée functions enable to perform the pre-processing for immersed boundary conditions (IBC). Cassiopee helps finding the IBC corrected points and interpolation points and their donor information (interpolation cells and coefficients).

Given a close surface and a input mesh (generally an octree), the algorithm is the following:
- The input mesh is blanked using Connector.blankCells in order to determine cells lying inside the surface.
- Then a fringe of n layers of cells is built using Connector.setHoleInterpolatedPts, starting from the outter layer of blanked cells. The cell centers are the IBC points.
- The normals to the IBC points is then computed as the gradient of the distance function using Dist2Walls.distance2Walls and Post.computeGrad.
- A second fringe of points is built by shifting the IBC points of δ .n, where δ is given.

These points are interpolated from the original mesh. The donor information is provided by Connector.setInterpolations for the points of the δ front for use with the solver.
         
              Landing gear surface (closed and watertight).

         
              Blanked points of the original mesh.

         
              Closeup view of IBC points near the surface.

         
              Closeup view of δ points .

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