Investigation of Wall-Detached Turbulence in the Atmospheric Surface Layer through LiDAR and Sonic-Anemometer Measurements

In the context of wall-bounded turbulence, the enhanced measurements capabilities currently available to probe turbulence at very high Reynolds numbers have re-ignited investigations on Large- and Very Large-Scales of Motion (LSM and VLSM). Specifically, the contribution to the Reynolds stresses carried by detached eddies have been recently investigated for a wide range of Reynolds numbers $(Re_{\tau }={10}^{3}$ to ${10}^{6})$. In this scenario, the present work focuses on a high-Reynolds number atmospheric surface layer flow probed with scanning Doppler wind LiDARs, sonic anemometers and a ceilometer at the SLTEST facility in Utah. Based on these new experimental datasets, the presence of detached eddies has been quantified throughout the whole surface layer and a possible theoretical background is provided to motivate the observed wall-normal profiles of the streamwise Reynolds stress. The contribution of this work is dual: first, the capability of the LiDAR technology to probe near-wall atmospheric turbulence is assessed; second, a theoretical support to the knowledge about the physics underlying wall-detached eddies is provided