Here is an overview on my most relevant publications in peer-reviewed international journals.

Transition from geostrophic flows to inertia-gravity waves in the spectrum of a differentially heated rotating annulus experiment.

By Costanza Rodda and Uwe Harlander

This article is published in the special collection “Multi-scale Dynamics of gravity waves” in the Journal of Atmospheric Science (JAS)

A long-standing question is what causes the -5/3 slope in the atmospheric spectra at the mesoscale: is it turbulence? Gravity waves? Something else?

In this work, we use a laboratory experiment-the differentially heated rotating annulus-to investigate the problem. Our experimental spectra show striking similarities to the atmospheric one. By separating the spectra into the vortex and wave component, it emerges that at the large-scale end of the mesoscale the gravity waves observed in the experiment cause a flattening of the spectra and provide most of the energy. At smaller scales, our data analysis suggests a transition towards a turbulent regime with a forward energy cascade up to where dissipation by diffusive processes occurs.

A new atmospheric-like differentially heated rotating annulus configuration to study gravity wave emission from jets and fronts.

By Costanza Rodda, Steffen Hien, Ulrich Achatz, and Uwe Harlander

This article is published in the journal Experiments in Fluids

A new configuration of the classical baroclinic annulus experiment, recently built at the BTU laboratory, is presented in this paper. We called this experiment the “atmospheric-like” differentially heated rotating annulus for its characteristic aspect ratio that makes it more similar to the Earth’s atmosphere.

The first evidence of gravity waves emitted from the baroclinic jet is reported. The conditions for gravity wave emission and propagation in this particular experimental set-up are examined in detail with the support of comparable numerical simulations. It emerges that, due to the complex horizontal structure of the buoyancy frequency N, where the largest values occur along the baroclinic jet axis, the gravity waves in the experiment are observed to be trapped.

Baroclinic, Kelvin and inertia-gravity waves in the barostrat instability experiment

By Costanza Rodda, Ion Dan Borcia, Patrice Le Gal, Miklos Vincze, and Uwe Harlander

This article is published in the journal Geophysical and Astrophysical Fluid Dynamics

In the present study, we investigate a modified version of the classic baroclinic experiment, the barostrat experiment, in which a juxtaposition of convective and motionless stratified layers is created by introducing a vertical salt stratification. 

The thermal convective motions are suppressed in a central region at mid-depth of the rotating tank, therefore double-diffusive convection rolls can develop only in thin layers located at top and bottom, where the salt stratification is weakest. For high enough rotation rates, the baroclinic instability destabilises the flow in the top and the bottom shallow convective layers, generating cyclonic and anticyclonic eddies separated by the stable stratified layer. Thanks to this alternation of layers resembling the convective and radiative layers of stars, the planetary’s atmospheric troposphere and stratosphere or turbulent layers at the sea surface above stratified waters, this new laboratory setup is of interest for both astrophysics and geophysical sciences.

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