Volume 4 Issue 2
Jun.  2011
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Stefano PAGLIARA, Thendiyath ROSHNI, Iacopo CARNACINA. 2011: Turbulence, aeration and bubble features of air-water flows over macro- and intermediate roughness. Water Science and Engineering, 4(2): 170-184. doi: 10.3882/j.issn.1674-2370.2011.02.005
Citation: Stefano PAGLIARA, Thendiyath ROSHNI, Iacopo CARNACINA. 2011: Turbulence, aeration and bubble features of air-water flows over macro- and intermediate roughness. Water Science and Engineering, 4(2): 170-184. doi: 10.3882/j.issn.1674-2370.2011.02.005
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Turbulence, aeration and bubble features of air-water flows over macro- and intermediate roughness

doi: 10.3882/j.issn.1674-2370.2011.02.005

  • Department of Civil Engineering, University of Pisa, Via Gabba 22, Pisa 56122, Italy  

  • Received Date: 2010-07-09
  • Rev Recd Date: 2011-06-02
    Abstract
  • Free surface flows in macro- and intermediate roughness conditions have a high aeration potential in which the flow characteristics vary with slopes and discharges. The underlying phenomenon of two phase flow characteristics in the macro and intermediate roughness conditions were analyzed in a setup assembled at the PITLAB center of the University of Pisa, Italy. Crushed angular rocks and hemispherical boulders were used to intensify the roughness nature of the bed. Flow discharges per unit width ranging between 0.03 m2/s and 0.09 m2/s and slopes between 0.26 and 0.46 were tested over different arrangements of rough bed. Analyses were mainly concentrated in the inner flow region which constitutes both bubbly and intermediate flow region. The findings revealed that two phase flow properties over rough bed were very much affected by the different rough bed arrangement. Turbulence features of two phase flows over rough beds were compared with that of the stepped chute data under similar flow conditions. Overall the results highlighted the flow features in the inner layers of the two phase flow.

     

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