Towards an improved spatial representation of a boundary layer from the attached eddy model

This study compares the predicted synthetic flow fields generated based on the representative structures of the attached eddy model to experimental data captured using Particle Image Velocimetry of a turbulent boundary layer. To this end, wall-parallel and cross-stream planar fields are analyzed qualitatively and quantitatively by examining instantaneous flow features and by statistical two-point correlation functions, respectively. Our results reveal that although single-point flow statistics are in good agreement with the experimental data, a comparison of instantaneous flow fields and multipoint statistics between the attached eddy model and experiments shows differences in the spatial coherence. Based on these observations, a modification to the placement of the representative eddies in the attached eddy model is proposed that incorporates the meandering of these flow structures, which has been extensively reported in turbulent boundary layers. Our results reveal that this subtle modification provides a superior spatial representation of a turbulent boundary layer from the attached eddy model by reducing periodic effects and the overestimated spatial coherence. Similar improvements are also reported for the spatial representation of the span wise velocity component.