Imperial College London

DrCostanzaRodda

Faculty of EngineeringDepartment of Civil and Environmental Engineering

Lecturer in Fluid Mechanics
 
 
 
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Contact

 

c.rodda

 
 
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Location

 

Skempton BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

11 results found

Rodda C, Savaro C, Bouillaut V, Augier P, Sommeria J, Valran T, Viboud S, Mordant Net al., 2023, From internal waves to turbulence in a stably stratified fluid, Physical Review Letters, Vol: 131, ISSN: 0031-9007

We report on the statistical analysis of stratified turbulence forced by large-scale waves. The setup mimics some features of the tidal forcing of turbulence in the ocean interior at submesoscales. Our experiments are performed in the large-scale Coriolis facility in Grenoble which is 13 m in diameter and 1 m deep. Four wave makers excite large-scale waves of moderate amplitude. In addition to weak internal wave turbulence at large scales, we observe strongly nonlinear waves, the breaking of which triggers intermittently strong turbulence at small scales. A transition to strongly nonlinear turbulence is observed at smaller scales. Our measurements are reminiscent of oceanic observations. Despite similarities with the empirical Garrett and Munk spectrum that assumes weak wave turbulence, our observed energy spectra are rather to be attributed to strongly nonlinear internal waves.

Journal article

Vincze M, Hancock C, Harlander U, Rodda C, Speer Ket al., 2023, Extreme temperature fluctuations in laboratory models of the mid-latitude atmospheric circulation, Scientific Reports, Vol: 13, ISSN: 2045-2322

Using two laboratory-scale conceptual fluid dynamic models of the mid-latitude atmospheric circulation we investigate the statistical properties of pointwise temperature signals obtained in long experiment runs. We explore how the average "equator-to-pole" temperature contrast influences the range and the jump distribution of extreme temperature fluctuations, the ratio of the frequencies of rapid cooling and warming events, and the persistence of "weather" in the set-ups. We find simple combinations of the control parameters-temperature gradient, rotation rate and geometric dimensions-which appear to determine certain scaling properties of these statistics, shedding light on the underlying dynamics of the Rossby wave-related elements of the mid-latitude weather variability.

Journal article

Harlander U, Sukhanovskii A, Abide S, Borcia ID, Popova E, Rodda C, Vasiliev A, Vincze Met al., 2023, New Laboratory Experiments to Study the Large-Scale Circulation and Climate Dynamics, ATMOSPHERE, Vol: 14

Journal article

Rodda C, Savaro C, Davis G, Reneuve J, Augier P, Sommeria J, Valran T, Viboud S, Mordant Net al., 2022, Experimental observations of internal wave turbulence transition in a stratified fluid, PHYSICAL REVIEW FLUIDS, Vol: 7, ISSN: 2469-990X

Journal article

Rodda C, Harlander U, Vincze M, 2022, Jet stream variability in a polar warming scenario – a laboratory perspective, Weather and Climate Dynamics, Vol: 3, Pages: 937-950, ISSN: 2698-4016

We report on a set of laboratory experiments to investigate the effect of polar warming on the mid-latitude jet stream. Our results show that a progressive decrease in the meridional temperature difference slows down the eastward propagation of the jet stream and complexifies its structure. Temperature variability decreases in relation to the laboratory “Arctic warming” only at locations representing the Earth's polar and mid-latitudes, which are influenced by the jet stream, whilst such a trend is reversed in the subtropical region south of the simulated jet. The reduced variability results in narrower temperature distributions and hence milder extreme events. However, our experiments also show that the frequency of such events increases at polar and mid-latitudes with decreased meridional temperature difference, whilst it decreases towards the subtropics. Despite missing land–sea contrast in the laboratory model, we find qualitatively similar trends of temperature variability and extreme events in the experimental data and the National Centers for Environmental Prediction (NCEP) reanalysis data.

Journal article

Harlander U, Borcia ID, Vincze M, Rodda Cet al., 2022, Probability Distribution of Extreme Events in a Baroclinic Wave Laboratory Experiment, FLUIDS, Vol: 7

Journal article

Vincze M, Bozóki T, Herein M, Borcia ID, Harlander U, Horicsányi A, Nyerges A, Rodda C, Pál A, Pálfy Jet al., 2021, The Drake Passage opening from an experimental fluid dynamics point of view, Scientific Reports, Vol: 11, ISSN: 2045-2322

Pronounced global cooling around the Eocene–Oligocene transition (EOT) was a pivotal event in Earth’s climate history, controversially associated with the opening of the Drake Passage. Using a physical laboratory model we revisit the fluid dynamics of this marked reorganization of ocean circulation. Here we show, seemingly contradicting paleoclimate records, that in our experiments opening the pathway yields higher values of mean water surface temperature than the “closed” configuration. This mismatch points to the importance of the role ice albedo feedback plays in the investigated EOT-like transition, a component that is not captured in the laboratory model. Our conclusion is supported by numerical simulations performed in a global climate model (GCM) of intermediate complexity, where both “closed” and “open” configurations were explored, with and without active sea ice dynamics. The GCM results indicate that sea surface temperatures would change in the opposite direction following an opening event in the two sea ice dynamics settings, and the results are therefore consistent both with the laboratory experiment (slight warming after opening) and the paleoclimatic data (pronounced cooling after opening). It follows that in the hypothetical case of an initially ice-free Antarctica the continent could have become even warmer after the opening, a scenario not indicated by paleotemperature reconstructions.

Journal article

Rodda C, Harlander U, 2020, Transition from geostrophic flows to inertia–gravity waves in the spectrum of a differentially heated rotating annulus experiment, Journal of the Atmospheric Sciences, Vol: 77, Pages: 2793-2806, ISSN: 0022-4928

Inertia–gravity waves (IGWs) play an essential role in the terrestrial atmospheric dynamics as they can lead to energy and momentum flux when propagating upward. An open question is to what extent IGWs contribute to the total energy and to the flattening of the energy spectrum observed at the mesoscale. In this work, we present an experimental investigation of the energy distribution between the large-scale balanced flow and the small-scale imbalanced flow. Weakly nonlinear IGWs emitted from baroclinic jets are observed in the differentially heated rotating annulus experiment. Similar to the atmospheric spectra, the experimental kinetic energy spectra reveal the typical subdivision into two distinct regimes with slopes k−3 for the large scales and k−5/3 for the small scales. By separating the spectra into the vortex and wave components, 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 toward a turbulent regime with a forward energy cascade up to where dissipation by diffusive processes occurs.

Journal article

Rodda C, Hien S, Achatz U, Harlander Uet al., 2020, A new atmospheric-like differentially heated rotating annulus configuration to study gravity wave emission from jets and fronts, Experiments in Fluids: experimental methods and their applications to fluid flow, Vol: 61, ISSN: 0723-4864

Significant inertia-gravity wave activity has been frequently observed in the vicinity of jet and front systems in the atmosphere. Although many studies have established the importance of these non-orographic sources, the mechanisms responsible for spontaneous wave emissions are still not fully understood. The complexity of the three-dimensional flow pattern and distribution of the sources over large areas point towards the need for laboratory experiments and idealised numerical simulations. These will help understand the correct interpretation of the fundamental dynamical processes in a simplified, but yet realistic flow. In this study, we emphasise the importance of using set-ups of the differentially heated rotating annulus experiment with a ratio between the buoyancy frequency N, and the Coriolis parameter f larger than one to investigate atmosphere-like emission of gravity waves from baroclinic jets. Indeed, in the atmosphere N∕f ∼ 100, but for table-top size experiments this ratio is smaller than one, resulting in an unfavourable condition for the propagation of gravity waves. For this reason, we offer a newly built laboratory experiment supported by numerical simulations that allow N∕f > 1. The conditions for gravity wave emission in this new configuration are examined in detail, and the first evidence of IGWs is reported. Moreover, we compare numerical simulations and experimental data focusing on the variations of the temperature T, and its effects on the buoyancy frequency N. It becomes clear, that despite the fact the global structure and baroclinic instability characteristics are very similar, the model and experiment show deviations in N with implications for gravity wave emission. Due to the complex horizontal structure of N, where the largest values occur along the baroclinic jet axis, the inertia-gravity waves in the experiment are observed to be trapped.

Journal article

Rodda C, 2019, Gravity wave emission from jet systems in the differentially heated rotating annulus experiment, Publisher: Cuvillier Verlag, ISBN: 9783736961104

This work proposes an experimental laboratory investigation of gravity waves generated from baroclinic jets and fronts using a differentially heated rotating annulus.

Book

Rodda C, Borcia ID, Le Gal P, Vincze M, Harlander Uet al., 2018, Baroclinic, Kelvin and inertia-gravity waves in the barostrat instability experiment, GEOPHYSICAL AND ASTROPHYSICAL FLUID DYNAMICS, Vol: 112, Pages: 175-206, ISSN: 0309-1929

Journal article

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