Sistema ETD

Archivio digitale delle tesi discusse presso l'Università di Pisa

 

Tesi etd-01182017-104701


Tipo di tesi
Tesi di laurea magistrale
Autore
GAGGINI, GABRIELE
URN
etd-01182017-104701
Titolo
EXPERIMENTAL AND NUMERICAL INVESTIGATION ON SEPARATION CONTROL THROUGH CONTOURED TRANSVERSE GROOVES
Struttura
INGEGNERIA CIVILE E INDUSTRIALE
Corso di studi
INGEGNERIA AEROSPAZIALE
Commissione
relatore Prof.ssa Salvetti, Maria Vittoria
relatore Prof. Buresti, Guido
relatore Dott. Mariotti, Alessandro
Parole chiave
  • experimental
  • numerical
  • flow control
  • grooves
  • boat tail
Data inizio appello
21/02/2017;
Consultabilità
parziale
Data di rilascio
21/02/2020
Riassunto analitico
The present work describes the results of an experimental and numerical investigation aimed at characterizing the performance of a recently introduced passive method to delay flow separation. The technique is based on the use of suitably-shaped transverse grooves.
In previous works small contoured cavities were shown to be able to delay flow separation and to increase the efficiency of diffusers in both laminar and turbulent flow. Now we apply the same flow control strategy to an external flow, by introducing one transverse groove, i.e. a small cavity, over different boat tails applied on the rear portion of an axisymmetric body whose configuration without boat-tail had already been investigated experimentally and numerically. Boat-tailing is a well-known drag reduction method and consists in a gradual decrease of the body cross-section before a sharp-edged base, where the pressure is consequently increased. The drag-reducing performance of boat tails improves with the reduction of the base cross-section, but only as long as no significant boundary-layer separation is present over the lateral surface. Hence, we combine boat-tailing with properly contoured transverse grooves to delay boundary-layer separation and thus to further reduce the pressure drag.
The effectiveness of the proposed strategy is assessed through a synergic use of wind tunnel tests and Variational MultiScale Large-Eddy Simulations (VMS-LES).
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