Three-dimensional spanwise coherence and extreme-force generation

Determine, using force-resolved three-dimensional calculations, whether the near-trailing-edge vortex interaction remains locally correlated, how rapidly the interacting vortices lose spanwise coherence, and what spanwise extent is required to produce an appreciable integrated force excursion.

Background

The paper establishes the extreme-drag mechanism primarily in two-dimensional, spanwise-coherent simulations, where closely spaced vortices interact near the trailing edge and generate a strong pressure footprint. In three-dimensional flow, spanwise deformation, vortex stretching, and secondary instabilities may preserve, weaken, or localize this interaction.

The authors identify spanwise coherence length as a potentially important determinant of whether a strong sectional response produces a substantial span-integrated force excursion. The unresolved issue is therefore to characterize the persistence, loss, and required extent of spanwise correlation in fully three-dimensional flow using force-resolved simulations.