Eddy diffusivity

Turbulence and Mixing at a Density Interface

Turbulence and Mixing at a Density Interface

The research group focuses on analyzing the vertical mixing that characterizes the interface of stratified currents by means of laboratory experiments. Such phenomenon is of fundamental importance in many environmental contexts, such as slope currents generated on mountain slopes, and in many other physical-engineering contexts characterized by turbulent mixing. Velocity measurements are taken using laser velocimetry, while density measurements are taken using image analysis. 

Eulerian and Lagrangian time scales of the turbulence above staggered arrays of cubical obstacles

We present results from water-channel experiments on neutrally-stable turbulent flows over staggered arrays of cubical obstacles modelling idealised urban canopies. Attention is concentrated on the vertical profiles of the Eulerian (TE) and Lagrangian (TL) time scales of the turbulence above three canopies with different plan area fractions (λP = 0.1, 0.25 and 0.4). The results show that both the streamwise and vertical components of TL increase approximately linearly with height above the obstacles, supporting Raupach’s linear law.

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