Giulio Dolcetti

I am a Research Associate, working at the development of a non-invasive airborne acoustic technique aimed at monitoring free surface turbulent flows. I hold a BSc in Aerospace Engineering from the University of Padua (Italy), a MSc in Mechanical Engineering from the University of Ferrara (Italy), and PhD in Mechanical Engineering from the University of Sheffield. I am part of the Pennine Water Group (PWG) as well as of the Dynamic Research Group (DRG), both based at the University of Sheffield. I am Associate Member of the Acoustical Society of America (ASA).

Research interests:

My research interests are in the dynamics of the free surface of shallow turbulent flows, and in the remote characterisation of free surface flows. Topics of research include the dynamics of dispersive gravity-capillary waves in finite-depth sheared flows, the scattering of airborne ultrasound by rough dynamic rigid surfaces, and inversion techniques applied to the reconstruction of the rough surface. The typical research approach involves laboratory experiments as well as both analytical and numerical modelling.

I am currently working at the EPRSC funded project named ‘Acoustic technique to monitor dynamics of water systems’ (EP/N029437/1), under the supervision of Dr Anton Krynkin.

The evidence of a direct link between the dynamics of the water surface and the hydraulic conditions in turbulent shallow flows, such as small rivers and partially filled pipes, has been accumulating in the past few years. This link would allow the development of a new range of inexpensive and robust sensors that can measure the hydraulic conditions of these flows remotely, based on the observation of the surface dynamics. Their development has been hindered so far by the limitations of traditional surface measurement techniques, such as those based on optics. Acoustic methods, in turn, have a great potential, since water is not transparent to ultrasound.

The project combines inversion techniques that have been developed for acoustic holography and imaging methods more common in optics, in order to obtain the reconstruction of the instantaneous three-dimensional shape of the water surface based on the measurement of scattered ultrasound recorded by arrays of sensors. The method has already been validated both numerically and experimentally with two-dimensional static surfaces. Aims of the project are the extension to three-dimensional dynamic surfaces, the identification of the optimal sensors arrangement, and the estimation of the measurement accuracy for a wide range of surface behaviours. These steps will inform the design of a prototype for field testing.

Measurement of the water surface dynamics in shallow turbulent flows. Dispersion relation of the water surface.

Numerical validation of the reconstruction of a three-dimensional rough surface based on the acoustic holography technique. Left is the actual surface, right is reconstructed.

In 2015 I was part of an amazing project named ‘SoundStream’, together with the electroacoustic composer Stephen Theofanous. We attempted to convey the spatial and dynamical complexity of the water surface in an audible way, by transforming the recordings of the surface elevation, obtained with standard laboratory sensors, into music. You can find some footage of one of the rare live performances, and a better quality audio-only piece here. The sounds in the latter were fragments of actual experimental data recorded in a laboratory flume.

I am part of a Sheffield-based group of early-career researchers and professionals with an interest in acoustics. Some information about our past and current activity can be found here.

Publications:

Journal publications

G Dolcetti and A Krynkin, (2017) Doppler spectra of airborne ultrasound forward scattered by the rough surface of open channel turbulent water flows, The Journal of the Acoustical Society of America, 142(5), 3122-3134
G Dolcetti, A Krynkin, and K V Horoshenkov, (2017) Doppler spectra of airborne sound backscattered by the free surface of a shallow turbulent flow, The Journal of the Acoustical Society of America, 142(6), 3387-3401
A Krynkin, G Dolcetti and S Hunting, (2017) Acoustic imaging in application to reconstruction of rough rigid surface with airborne ultrasound waves, Review of Scientific Instruments, 88(2), 0.24901
G Dolcetti, KV Horoshenkov, A Krynkin and SJ Tait (2016) Frequency-wavenumber spectrum of the free surface of shallow turbulent flows over a rough boundary, Physics of Fluids, 28(10), 105105

Published conference proceedings

G Dolcetti and A Krynkin (2016) Reconstruction of the dynamic surface roughness with acoustic imaging technique, The Journal of the Acoustical Society of America, 140(4), 3024 (abstract)
A Krynkin, G Dolcetti, and KV Horoshenkov (2015) Use of scattered airborne acoustics wavefield to recover profile of surface of shallow water flow, Proceedings of the Institute of Acoustics 37(2), 231-233.
G Dolcetti, A Krynkin, KV Horoshenkov (2015) Characterisation of the free-surface, turbulent, water flows with an array of ultrasonic sensors, Proceedings of the 22nd International Congress on Sound and Vibration, 4, 2745-2750
G Dolcetti, A Krynkin, KV Horoshenkov and SJ Tait (2015) Analysis of scattered acoustic signals to characterise the behaviour of the free surface of shallow water flows, E-Proceedings of the 36th IAHR World Congress, 28
G Dolcetti, A Krynkin, KV Horoshenkov and SJ Tait (2014) The spectrum of the acoustic waves backscattered by the dynamic rough surface of a shallow water flow, Proceedings of the Institute of Acoustics 36(3), 422-429.

PhD thesis

G Dolcetti (2017) Remote monitoring of shallow turbulent flows based on the Doppler spectra of airborne ultrasound (Doctoral dissertation, The University of Sheffield)