A characterization of the flow around a surface mounted cube by TR-PIV and 3D Shake-The-Box

Abstract

The flow around a surface mounted cube with incoming turbulent boundary layer has been topic of many experimental and numerical investigations in the past decades. Despite its simple geometry the flow generates a set of complex vortical structures, includes flow separation at the three front plane edges with corresponding subsequent shear layer dynamics and recirculation zones and organizes a large unsteady flow separation region downstream of the cube which is associated with typical quasi-periodic bluff-body wake dynamics. Because of its generic role for geometry induced flow separation and ist complex unsteady vortical properties the flow around a surface mounted cube is often used for benchmarking purposes to validate turbulence models and advanced numerical methods, while an increasing interest of DNS investigations in the recent years including the laminar boundary layer flow case can be registered. Furthermore, the flow configuration is well suited to enhance the understanding of similar unsteady and separated flow phenomena in many aerodynamic and engineering applications. In the present experimental investigation we aim at resolving a large spectrum of spatial and temporal scales in the flow around a cube with incoming laminar and turbulent boundary layers by using the most recent developments of 3D Lagrangian Particle Tracking (LPT) and high resolution TR-PIV. The results are partly documented in the present paper and consist of long time-series of highly resolved 3D and 2D velocity fields as well as unsteady 3D pressure volumes allowing for the analysis of coherent structure dynamics and of corresponding statistical Lagrangian and Eulerian flow properties.