Characterization of near-wall turbulence in ZPG-TBL flows using dense 3D Lagrangian Particle Tracking

Abstract

The 3D Lagrangian particle tracking method Shake-The-Box (STB) and, subsequently, the data assimilation method FlowFit have been applied to a measurement volume inside the near-wall region of a zero-pressure-gradient (ZPG) turbulent boundary layer (TBL) flow at various Reynolds numbers in order to fully resolve the flow inside the viscous sub-, buffer- and lower logarithmic- layer in space and time. As a result, we gained time-series of dense 3D velocity, acceleration and pressure fields including both components of the instantaneous wall-shear stresses suited for (conditional) analysis of coherent structures, rare (e.g. back flow) events and one- and multi-point statistics. The experiments were conducted in the 1m- wind tunnel facility of DLR in Göttingen.