HYDRAULIC ANALYSIS OF OXYGEN TRANSFER THROUGH AIR ENTRAINMENT IN RIPARIAN RIFFLES

  • 발행 : 2003.07.01

초록

This paper presents the hydraulic analysis of the oxygen transfer through the air entrainment and the relationships between the efficiency of the oxygen transfer and the hydraulic parameters in the riparian riffles. Field survey on the pool-riffle formation of the river reach and the measurements of the oxygen transfer in the riffles were performed. Air entrainment occurred more frequently in the edged gravels rather than in the round and edgeless ones, and it was formed mainly from behind the trailing edges of the gravels. Oxygen transfer was found to be proportional to the flow velocity, the flow discharge, and the Froude number, but to be not closely related to the particle diameter. Average value of oxygen transfer in the riffles of study area was about 0.085, which shows good efficiency compared with results of smooth chute. Variation of the water level, which increases in proportion to the flow velocity and the flow discharge, seems to make the air entrainment more active, but has not been verified quantitatively. Relationships between the air entrainment and the variation of the water level must be considered in the further study.

키워드

참고문헌

  1. Avery, S.T. and Novak, P. (1978). 'Oxygen transfer at hydraulic structures,' Journal of the Hydraulics Division, ASCE, Vol. 104, No. 11, pp. 1521-1540
  2. Chanson, H. (1993), 'Self-aerated flows on chute and spillways,' Journal of the Hydraulic Engineering, ASCE, Vol. 119, No. 2, pp. 220-243 https://doi.org/10.1061/(ASCE)0733-9429(1993)119:2(220)
  3. Chanson, H. (1977). 'Measuring aur-water interface area in supercritical open channel flow,' Water Research, IAWPRC, Vol. 31, No. 6, pp. 1414-1420 https://doi.org/10.1016/S0043-1354(96)00339-9
  4. Gullivers, J.S., Thene, J.R., and Rindels, A.J., (1990), 'Indexing gas transfer in self-aerated flows,' Journal of Environmental Engineering, ASCE, Vol. 117, No. 3, pp. 503-523
  5. Henry, T. (1985). Air-water flow in hydraulic structures, Water Resources Technical Publication, Engineering Monograph No. 41, pp. 251-285
  6. Itakura, T. and Kishi, T. (1980). 'Open channel flow with suspended sediments,' Journal of the Hydraulics Division, ASCE, Vol. 106, No. 8, pp. 1345-1352
  7. Kim, J.H. and Park, J.S. (1999). 'Hydraulic analysis on the riparian habitat.' Proceedings of 1999 KWRA, No. 2, pp. 566-571. (in Korean)
  8. Lee, H.S. and Kim, J.H. (1999). 'Site investigation on the flow features of the self-aerated riffles.' Proceedings of 1999 KSCE, No. 2, pp. 315-318. (In Korean)
  9. Tamai, N., Mizuno, N., and Nakamura, S. (1993). Environmental river engineering, University of Tokyo, Tokyo, pp. 125-128. (In Japanese)