Evaluation of the topological characteristics of the turbulent flow in a ‘box of turbulence’ through 2D time-resolved particle image velocimetry

Attached eddy-like particle clustering in a turbulent boundary layer under net sedimentation conditions

“…The so-called sweep–stick mechanism, which describes that inertial particles stick to the fluid-phase zero-acceleration points to form clusters (Goto & Vassilicos 2008; Coleman & Vassilicos 2009; Lian, Soulopoulos & Hardalupas 2017), does not conflict with the present conceptual model, since the converging Q2–Q4 events associated with back ridges of wall-attached negative -structures might provide a source for the formation of zero-acceleration points. However, a detailed examination on this aspect is beyond the scope of the present study and deserves to be further studied in the future.…”