Scour downstream of an apron due to submerged horizontal jets

被引:130
作者
Dey, S [1 ]
Sarkar, A [1 ]
机构
[1] Indian Inst Technol, Dept Civil Engn, Kharagpur 721302, W Bengal, India
关键词
aprons; erosion; open channels; submerged jets; scour; sediment transport; hydraulics;
D O I
10.1061/(ASCE)0733-9429(2006)132:3(246)
中图分类号
TU [建筑科学];
学科分类号
0813 ;
摘要
The results of an experimental investigation on scour of noncohesive sediment beds (uniform and nonuniform sediments) downstream of an apron due to a submerged horizontal jet issuing from a sluice opening are presented. Attempts are made to explain the similarity existing in the scour process and profiles (including dune in the downstream of the scour hole). The scour profiles at different times follow a particular geometrical similarity and can be expressed by the combination of two polynomials. Using experimental scour depth at different times, the time variation of scour depth is scaled by an exponential law, where time scale increases linearly with densimetric Froude number. The equilibrium scour depth, related to the sediment size relative to the sluice opening, decreases with increase in sediment size and sluice opening. On the other hand, the equilibrium scour depth increases with increase in densimetric Froude number. The variation of equilibrium scour depth with tailwater depth indicates a critical tailwater depth corresponding to a minimum equilibrium scour depth. The effect of sediment gradation on scour depth is pronounced for nonuniform sediments, which reduce scour depth significantly due to formation of an armor layer, and therefore prompted study of the reduction of scour depth by a launching apron placed downstream of the rigid apron. The results show that the average reduction of scour depth by placing a launching apron was 39%, having a maximum of 57.3% and a minimum of 16.2%. The characteristic parameters affecting maximum equilibrium scour depth are identified based on the physical reasoning and dimensional analysis. Equation of maximum equilibrium scour depth obtained empirically agrees well with the experimental data.
引用
收藏
页码:246 / 257
页数:12
相关论文
共 25 条
  • [1] Effect of sediment gradation on erosion by plane turbulent wall jets
    Aderibigbe, O
    Rajaratnam, N
    [J]. JOURNAL OF HYDRAULIC ENGINEERING-ASCE, 1998, 124 (10): : 1034 - 1042
  • [2] LOCAL SCOUR CAUSED BY SUBMERGED WALL JETS
    ALI, KHM
    LIM, SY
    [J]. PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS PART 2-RESEARCH AND THEORY, 1986, 81 : 607 - 645
  • [3] Local channel scour in uniformly graded sediments: the time-scale problem
    Balachandar, R
    Kells, JA
    [J]. CANADIAN JOURNAL OF CIVIL ENGINEERING, 1997, 24 (05) : 799 - 807
  • [4] Instantaneous water surface and bed scour profiles using video image analysis
    Balachandar, R
    Kells, JA
    [J]. CANADIAN JOURNAL OF CIVIL ENGINEERING, 1998, 25 (04) : 662 - 667
  • [5] The effect of tailwater depth on the dynamics of local scour
    Balachandar, R
    Kells, JA
    Thiessen, RJ
    [J]. CANADIAN JOURNAL OF CIVIL ENGINEERING, 2000, 27 (01) : 138 - 150
  • [6] BREUSERS HNC, 1965, PUBLICATION DELFT HY, V40
  • [7] CBIP, 1989, RIV BEH MAN TRAIN
  • [8] CHATTERJEE SS, 1980, J HYDR ENG DIV-ASCE, V106, P1765
  • [9] LOCAL SCOUR DUE TO SUBMERGED HORIZONTAL JET
    CHATTERJEE, SS
    GHOSH, SN
    CHATTERJEE, M
    [J]. JOURNAL OF HYDRAULIC ENGINEERING-ASCE, 1994, 120 (08): : 973 - 992
  • [10] CLEAR WATER SCOUR AT CIRCULAR PIERS - A MODEL
    DEY, S
    BOSE, SK
    SASTRY, GLN
    [J]. JOURNAL OF HYDRAULIC ENGINEERING-ASCE, 1995, 121 (12): : 869 - 876