Shake-The-Box-A versatile tool for characterization of turbulent flows

Abstract

Dense 3D Particle Tracking allows characterizing unsteady and turbulent flows within the Lagrangian and Eulerian frame of reference. The 3D Lagrangian Particle Tracking (LPT) method “Shake-The-Box” (STB) has been continuously developed during the past couple of years and is able to reliably and efficiently extract particle trajectories from volumetric flow measurements at unprecedented numbers. STB delivers accurate data on particles position, velocity and acceleration (material derivative) along densely distributed tracks. The STB method can be applied as well to short recording sequences, acquired with a multi- or two-pulse technique, allowing investigating high-speed flows at Reynolds numbers relevant for research in aerospace engineering. Subsequently, data assimilation approaches can be applied, which use Navier-Stokes-constraints for a linear or non-linear optimization process resulting in a continuous interpolation of the flow field with minimized deviation to the measurement data. With the new FlowFit3.0 (FF) version applied to dense LPT data the full time-resolved 3D velocity gradient tensor and pressure fields are available with high spatial and temporal resolution at high accuracy and low computational efforts.