Flow Feature Aligned Structured Mesh Generation via Sweeping Cross‐Field Generated Multiblocks

For accurately resolving flow features such as shocks and vortices, it is desirable for the mesh edges to be aligned or orthogonal to these features, which minimizes interpolation errors and allows the Rankine‐Hugoniot condition across discontinuities to be satisfied. For this, we develop a three‐dimensional structured mesh generation method that aligns hexahedral grids with flow features to improve resolution accuracy and efficiency. For this purpose, a novel sweeping strategy is introduced. We first generate two‐dimensional cross‐sectional meshes using the cross‐field method, and then extrude them into volumetric blocks. Flow features extracted from an initial solution are embedded as geometric constraints. A direction‐aware mechanism can handle two alternatives. If the feature's sweep direction aligns with the geometry, the feature curve is embedded directly into the cross‐sectional block. On the other hand, if they differ, a separate mesh domain is created for the feature and coupled via an overlapping grid strategy. Numerical tests on transonic flows show that the method captures λ‐shocks, tip vortices and wakes with far fewer cells than uniform refinement, while achieving comparable or better resolution. The resulting anisotropic grids suppress numerical dissipation along critical flow structures, offering a practical balance between computational cost and solution fidelity.