Turbulent Pipe Flow - High Resolution Measurements in CICLoPE

Fiorini, Tommaso (2017) Turbulent Pipe Flow - High Resolution Measurements in CICLoPE, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Meccanica e scienze avanzate dell'ingegneria, 29 Ciclo. DOI 10.6092/unibo/amsdottorato/8158.
Documenti full-text disponibili:
Documento PDF (English) - Richiede un lettore di PDF come Xpdf o Adobe Acrobat Reader
Disponibile con Licenza: Salvo eventuali più ampie autorizzazioni dell'autore, la tesi può essere liberamente consultata e può essere effettuato il salvataggio e la stampa di una copia per fini strettamente personali di studio, di ricerca e di insegnamento, con espresso divieto di qualunque utilizzo direttamente o indirettamente commerciale. Ogni altro diritto sul materiale è riservato.
Download (15MB) | Anteprima


The thesis deals with the experimental investigation of turbulent pipe flow at high Reynolds number. Wall-bounded turbulence is an extremely relevant topic for engineering and natural science applications and yet many aspects of the physics are not clear due to the difficulty in performing high Re experiments. To overcome these difficulties the CICLoPE Laboratory was developed, the main element of which is the Long Pipe wind tunnel. The facility is unique in its kind, as thanks to its large scale it delivers a flow quality and resolution that can not be achieved elsewhere at these Reynolds number. Reported here are the results from the first experimental campaign performed in the facility. A first part of the results presented concerns the characterization of this new facility. Flow quality and stability are assessed, particular attention is given to the characterization of pressure drop. The scaling of velocity fluctuations is analysed. The magnitude of the inner peak of the streamwise normal stress shows an increasing trend up to the highest Reynolds number examined, while no outer peak was clearly distinguishable from present measurements. Scaling of coherent motions is investigated via spectral analysis. An inner and outer spectral peaks are identified, with the former scaling in inner units while the latter neither following inner nor outer scaling, and increasing in magnitude with Re. Analysis of the spectra at y+ ≈ 15 shows how the increase of Reynolds normal stress is related to the influence of large scales in the inner wall region. Quadrant analysis was carried out on streamwise and wall-normal velocity fluctuations. The results show the important role in contribution to Reynolds shear stress of highly intermittent and strong events like ejections, that assume an even more intermittent and dominant role with the increase of Reynolds number.

Tipologia del documento
Tesi di dottorato
Fiorini, Tommaso
Dottorato di ricerca
Settore disciplinare
Settore concorsuale
Parole chiave
Wall turbulence, pipe flow, high Reynolds number, hot-wire, xwire, statistics, spectra, quadrant analysis.
Data di discussione
4 Maggio 2017

Altri metadati

Statistica sui download

Gestione del documento: Visualizza la tesi