Hydraulic Features of Air-Water Mixture Flow on a Staircase with Rest Platforms
Publication: Journal of Hydraulic Engineering
Volume 140, Issue 6
Abstract
To investigate hydraulic features of the flooding flow on a staircase with a rest platform, experiments were conducted on a 1:2-scale physical model of a staircase with a middle rest platform between two stair segments. The transition or skimming flow occurring on the first segment is similar to that on a stepped chute. However, a jet flow forms immediately downstream of the rest platform, followed by a redeveloping transition flow on the second segment. The measured profiles of air concentrations in those flow regions agree well with that in the skimming and transition flow known from stepped spillways. The amount of air entrained into the free-falling jet increases dramatically because of a higher air concentration in the approaching flow. Rapid rises of the air-water mixture depth and the flow velocity in part of the jet and the transition flow downstream were observed. These features could affect human maneuverability on a flooding staircase with rest platform(s) and make it more difficult for people to safely evacuate from underground spaces.
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Acknowledgments
The authors gratefully acknowledge the financial support by the Fundamental Research Funds for the Central Universities (No. 2009QNA4024) and the Program for Zhejiang Leading Team of S&T Innovation (2010R50037).
References
Bobylev, N. (2007). “Sustainability and vulnerability analysis of critical underground infrastructure.” Manage. Crit. Infrastruct. Risks, I. Linkov, et al., eds., Springer Press, 445–469.
Boes, R. M., and Hager, W. H. (2003). “Hydraulic design of stepped spillways.” J. Hydraul. Eng., 671–679.
Beijing Urban Engineering Design and Research Institute (BUEDRI). (2003). Code for design of metro, China Planning Press, Beijing, China.
Bung, D. B. (2011). “Developing flow in skimming flow regime on embankment stepped spillways.” J. Hydraul. Res., 49(5), 639–648.
Bung, D. B. (2013). “Non-intrusive detection of air-water surface roughness in self-aerated chute flows.” J. Hydraul. Res., 51(3), 322–329.
Cain, P. (1978). “Measurements within self-aerated flow on a large spillway.”, Dept. of Civil Engineering, Univ. of Canterbury, New Zealand, 650.
Chamani, M., and Rajaratnam, N. (1999). “Characteristics of skimming flow over stepped spillways.” J. Hydraul. Eng., 361–368.
Chanson, H. (1988). “A study of air entrainment and aeration devices on a spillway model.” Ph.D. thesis, Dept. of Civil Engineering, Univ. of Canterbury, Christchurch, New Zealand.
Chanson, H. (1989). “Study of air entrainment and aeration devices.” J. Hydraul. Res., 27(3), 301–319.
Chanson, H. (1992). “Air entrainment in chutes and spillways.” Research Rep., Dept. of Civil Engineering, Univ. of Queensland, Queensland, Australia.
Chanson, H. (2002). The hydraulics of stepped chutes and spillways, Balkema, Lisse, The Netherlands.
Chanson, H. (2006). “Hydraulics of skimming flows on stepped chutes: The effects of inflow conditions?.” J. Hydraul. Res., 44(1), 51–60.
Chanson, H., and Toombes, L. (2001). Experimental investigations of air entrainment in transition and skimming flows down a stepped chute: Application to embankment overflow stepped spillways, Dept. of Civil Engineering, Univ. of Queensland, Queensland, Australia.
Chanson, H., and Toombes, L. (2002a). “Air-water flows down stepped chutes: Turbulence and flow structure observations.” Int. J. Multiphase Flow, 28(11), 1737–1761.
Chanson, H., and Toombes, L. (2002b). “Experimental investigations of air entrainment in transition and skimming flows down a stepped chute.” Can. J. Civ. Eng., 29(1), 145–156.
Chanson, H., and Toombes, L. (2003). “Strong interactions between free-surface aeration and turbulence in an open channel flow.” Exp. Therm. Fluid Sci., 27(5), 525–535.
Chanson, H., and Toombes, L. (2004). “Hydraulics of stepped chutes: The transition flow.” J. Hydraul. Res., 42(1), 43–54.
Chanson, H., and Toombes, L. (2008). “Flow patterns in nappe flow regime down low gradient stepped chutes.” J. Hydraul. Res., 46(1), 4–14.
Committee of Countermeasures against Inundation Disasters in Underground Spaces (CCIDUS). (2002). Guideline for measures against inundation of underground spaces, Ministry of Land, Infrastructure, Transport, and Tourism (MLIT), Tokyo (in Japanese).
Gonzalez, C. A., and Chanson, H. (2004). “Interactions between cavity flow and main stream skimming flows: An experimental study.” Can. J. Civ. Eng., 31(1), 33–44.
Gonzalez, C. A., and Chanson, H. (2008). “Turbulence and cavity recirculation in air–water skimming flows.” J. Hydraul. Res., 46(1), 65–72.
Inoue, K., Toda, K., Nakai, T., Takemura, N., and Oyagi, R. (2003). “On the inundation process in the underground space.” Disaster Prev. Res. Inst., Kyoto University, 263–273 (in Japanese).
International Code Council. (2011). “2012 international building code (IBC).” Washington, DC.
Ishigaki, T., et al. (2005). “Experimental study on evacuation from underground space by using real size models.” Disaster Prev. Res. Inst. Kyoto Univ., 639–646.
Ishigaki, T., Kawanaka, R., Onishi, Y., Shimada, H., Toda, K., and Baba, Y. (2009). “Assessment of safety on evacuating route during underground flooding.” Adv. Water Resour. Hydraul. Eng.–Proc.,16th IAHR-APD Congress and 3rd Symp. of IAHR-ISHS, C. Zhang, H. Tang, eds., 141–146.
Ishigaki, T., Toda, K., and Inoue, K. (2003). “Hydraulic model tests of inundation in urban area with underground space.” Proc., 30th IAHR Biennial Congress, J. Ganoulis, P. Prinos, eds., Vol. B, 487–493.
Marchi, E. (1993). “On the free overfall.” J. Hydraul. Res., 31(6), 777–790.
Meireles, I., Renna, F., Matos, J., and Bombardelli, F. (2012). “Skimming, nonaerated flow on stepped spillways over roller compacted concrete dams.” J. Hydraul. Eng., 870–877.
Ministry of Housing and Urban-Rural Development of the People’s Republic of China (MOHURD). (2005). Code for design of civil buildings, Chinese Architecture and Building Press, Beijing, China.
Ohtsu, I., and Yasuda, Y. (1997). “Characteristics of flow conditions on stepped channels.” Proc., 27th IAHR Congress, John S. Gulliver, Pierre-Louis Viollet, eds., IAHR, San Francisco, 583–588.
Ohtsu, I., Yasuda, Y., and Takahashi, M. (2000). “Discussion of ‘Characteristics of skimming flow over stepped spillways’.” J. Hydraul. Eng., 869–871.
Ohtsu, I., Yasuda, Y., and Takahashi, M. (2004). “Flow characteristics of skimming flows in stepped channels.” J. Hydraul. Eng., 860–869.
Pfister, M. (2009). “Effect of control section on stepped spillway flow.” Proc., 33rd IAHR Congress: Water Engineering for a Sustainable Environment, Vancouver, 1964–1971.
Pfister, M. (2011). “Chute aerators: Steep deflectors and cavity subpressure.” J. Hydraul. Eng., 1208–1215.
Pfister, M., and Hager, W. H. (2009). “Air concentration characteristics of drop-and deflector-generated jets.” 33rd IAHR World Congress, Vol. 10230, Curran Associates, 4909–4916.
Pfister, M., and Hager, W. H. (2010). “Chute aerators. I: Air transport characteristics.” J. Hydraul. Eng., 352–359.
Pfister, M., and Hager, W. H. (2012). “Deflector-jets affected by pre-aerated approach flow.” J. Hydraul. Res., 50(2), 181–191.
Relvas, A. T., and Pinheiro, A. N. (2008). “Inception point and air concentration in flows on stepped chutes lined with wedge-shaped concrete blocks.” J. Hydraul. Eng., 1042–1051.
Shao, W.-Y. (2010). “Critical rainfall intensity for safe evacuation from underground spaces with flood prevention measures.” J. Zhejiang Univ. Sci. A, 11(9), 668–676.
Takedomi, K. (2001). “Experiments on difficult degree for people walking through the flooding stairs from underground space.” 2001 JSCE Annual Meeting, JSCE, Tokyo.
Teng, W. H., Hsu, M. H., Wu, C. H., and Chen, A. S. (2006). “Impact of flood disasters on Taiwan in the last quarter century.” Nat. Hazards, 37(1), 191–207.
Toda, K. (2007). “Urban flooding and measures.” J. Disaster Res., 2(3), 143–144.
Toombes, L., Wagner, C., and Chanson, H. (2008). “Flow patterns in nappe flow regime down low gradient stepped chutes.” J. Hydraul. Res., 46(1), 4–14.
Tozzi, M., Taniguchi, E., and Ota, J. (1998). “Air concentration in flows over stepped spillways.” Proc., ASME Fluids Engineering Conf., ASME, New York, 21–25.
Yang, J., Bao, Y.-Y., Lin, M.-L., Zhu, S., and Gao, Z.-M. (2013). “Experimental study and numerical simulation of local void fraction in cold-gassed and hot-sparged stirred reactors.” Chem. Eng. Sci., 100(11), 83–90.
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Published In
Journal of Hydraulic Engineering
Volume 140 • Issue 6 • June 2014
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Mar 26, 2013
Accepted: Jan 20, 2014
Published online: Feb 28, 2014
Published in print: Jun 1, 2014
Discussion open until: Jul 28, 2014
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