Geometric and Statistical Characterization of the Turbulent / Non-Turbulent Interface in a Turbulent Boundary Layer Flow Identified Using Uniform Momentum Zone Concepts

This poster presents a threshold-free method for identifying the turbulent/non-turbulent interface (TNTI) in zero-pressure-gradient turbulent boundary layers using uniform momentum zone (UMZ) concepts. Instead of relying on a prescribed vorticity or turbulent-kinetic-energy threshold, the UMZ-TNTI method identifies the interface from the first local minimum in the velocity probability density function near the free stream, making the approach less arbitrary and applicable to both DNS and 2C–2D PIV datasets. Using the Sillero et al. DNS dataset over Reτ ≈ 1000–2000, the poster characterises the geometric properties of the TNTI and compares them with previous experimental studies. Conditional statistics relative to the TNTI show good collapse across Reynolds numbers when normalised with local TNTI velocity and length scales, supporting the robustness of the UMZ-based interface definition.