Turbulent/non-turbulent interface identification using Poisson reconstruction

Abstract

This study introduces a novel methodology for identifying the turbulent/non-turbulent interface (TNTI) in turbulent flows using Poisson surface reconstruction. Traditional TNTI detection methods based on vorticity thresholding often either result in multi-layered isosurfaces or fail to accurately capture engulfment structures. By first generating a point cloud from vorticity-based threshold points and subsequently applying Poisson reconstruction, a smooth, single-layer, watertight surface is obtained that faithfully represents both the outer envelope and internal engulfment features of the TNTI. The method is applied to a large-eddy simulation of a separated and reattaching turbulent boundary layer behind a wall-mounted rib. Results demonstrate significant improvements in capturing the intricate topology of the TNTI, enabling detailed analysis of entrainment mechanisms. Statistical evaluations of interface height and entrainment rate reveal distinct flow regimes influenced by separation and reattachment, highlighting the efficacy of the proposed approach in advancing the understanding of turbulent interfacial dynamics.