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Turbulent wall-bounded flows

Visualization of the vorticity (enstrophy) of a turbulent flow near the wall with and without intermittency; white areas show low vorticity and black areas high vorticity.

Visualization of the vorticity (enstrophy) of a turbulent flow near the wall with and without intermittency; white areas show low vorticity and black areas high vorticity.
Image Credit: Cedrick Ansorge (python-matplotlib), CC-BY 4.0.

The Data

This data collection holds statistics of direct numerical simulations of turbulent wall-bounded flows serving the study of the atmospheric boundary layer (ABL) that were generated using the open-source code tLab (link: https://github.com/turbulencia/tlab). The ABL is the lower part of the earth atmosphere (1.5-2 km), in contact with the earth surface. The ABL is influenced by wall friction and roughness as well as heat exchange with the surface, but also by the rotation of the earth (Coriolis effect) and the large-scale forcing manifest in a pressure gradient and associated geostrophic wind.

The boundary condition commonly destabilizes the flow causing boundary-layer turbulence on time scales ranging from fractions of a second to hours. Not only does the ABL take on a key role in the earth system by sharing an interface with various of its compartments (land, ocean, land-ice, see-ice and the atmosphere), but also it is the part of the atmosphere where humans experience weather.

Data in this collection consider heavily idealized cases that, however, they are based on fundamental principles of fluid mechanics only (Navier—Stokes equations). Such separation of the ABL’s fluid mechanical aspects is useful to improve the process-based understanding of the ABL, since models of higher complexity (large-eddy simulations, meso-scale codes such as WRF or MM5, and weather forecasting, such as ICON, GFS, or IFS) normally do not allow for a clear process-attribution. Hence, this collection shall foster the improvement of turbulence parameterization, still subject to major uncertainties in larger-scale models for numerical weather prediction and climate projection. In particular, the data offers possibilities to check the assumptions underlying turbulence parameterizations a priori and a posteriori.

Publication of the dataset: Ansorge C, Kostelecky J (2024) https://refubium.fu-berlin.de/handle/fub188/43499