Gregory Burton | 19-FS-045
We developed the capability to move, on-the-fly, small-scale aeroshell boundary features, such as those caused by damage or ablation, during a single, high-speed, unsteady computational fluid dynamics (CFD) simulation. The work involved modifying a hypersonic unsteady flow code, known as MARGOT, developed at Lawrence Livermore National Laboratory, to (1) move prescribed portions of an aeroshell boundary using the free-form deformation method; (2) generate additional mesh cells in the newly created region using the radial basis function method; (3) refine the new mesh elements using a modified version of a MARGOT utility code; and (4) interpolate the last simulation result into the new mesh region and restarting.
The capability we developed is essential to (1) exploring unsteady thermal and dynamic loadings on aeroshell surfaces due to damage or ablation; (2) generating parameter-space databases needed for quantification of design margins and uncertainties; and (3) developing reduced-order models for damage lethality assessments using machine learning techniques. We demonstrated that boundaries in a high-resolution, unsteady, high-speed CFD calculation can be modified on-the-fly, and that the simulation can be restarted successfully from the last time before boundary modification.
Our project's findings support the Laboratory's national security mission, including exascale, ultra-high-resolution, hypersonic simulation capabilities. The work directly supports Livermore's hypersonics mission research challenge by developing advanced simulation capabilities with uncertainties for high-speed flow over an aeroshell.