Investigating the effect of submerged pipe diameter on the control of scour in river bed

Subject Areas : Subjects

Fariedeh karamzadeh ¹ (Department of Water Science and Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran.)
Alireza Masjedi ² (Department of Water Science and Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran.)
Mohammad Heidarnejad ³ (Department of Water Science and Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran.)
Amir Abbas Kamanbedast ⁴ (Department of Water Science and Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran.)
Amin Bordbar ⁵ (Department of Water Science and Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran.)

Received: 2018-10-28 Accepted : 2020-11-02 Published : 2020-10-22

Keywords: Blade, Pipe diameter, Scours depth, Submarine pipelines,

Abstract :

The effect of submerged pipe diameter on scour controlling a direct laboratory flume was experimentally studied. Experiments were carried out on a cylindrical pipe with or without a lower blade. For these experiments, four pipe diameters, four blade lengths, and five horizontal placement modes for the lower blade were considered using a constant discharge under clear-water conditions. At the end of each experiment, the length and depth of scour beneath the pipe were measured. According to the results, the location of the lower blade and increased pipe diameter affect the scour depth around the pipe. In all cases, the use of a longitudinal blade caused an increase in the percentage of scour depth reduction around the submerged pipe. For a pipe with a diameter of 3.1 cm, the use of a blade length of 2.5 cm downstream the center of the pipe reduced the scour length by 70% on average as compared to the pipe without a lower blade.

References:

1)        Chiew, Y., (1991), Prediction of maximum scour depth at submarine pipelines, Journal Hydraulic Engineering,117(4), p. 452-466.

2)        Ibrahim, A. and Nalluri, C., (1986), Scour prediction around marine pipelines, Proc.5th International Symp.on Offshore Mechanic and Arctic Engineering, Tokyo, Japan, p. 679-684.

3)        Kjeldsen, S. P., Gjørsvik, O., Bringaker, K. G., and Jacobsen, J., (1973), Local scour near offshore pipelines, Proc., 2nd International Conference on POAC, p. 308-331.

4)        Liang, D. and Cheng, L. (2005), Numerical modeling of flow and scour below a pipeline in currents, Part I. Flow simulation, Journal of Coastal Engineering, 52, p. 25-42.

5)        Mao, Y. (1986). The interaction between a pipeline and an erodible bed. Series Paper 39, Inst.of Hydrodyn. and Hydraulic Engrg., Tech. Univ. Denmark, in partial fulfillment of the requirements for the degree of Doctor of Philosophy.

6)        Maza, J.A. 1987. Introduction to river engineering. Advanced Course on Water Resources Management, University´ Italiana per Stranieri, Perugia, Italy,7.29,7.50,8.16course.

7)        Melville, B. W.; Chiew, Y.-M. (1999), Time scale for local scour at bridge piers, J. Hydraul. Eng.,125(1), 59–65.

8)        Moncada, M, A. T. and Aguirre, Pe, J., (1999), Scour below pipeline in river crossings, Journalof Hydraulic. Engineering, ASCE, 125(9), p. 953-958.

9)        Oliveto, G. and W. H. Hager. 2002. Temporal evolution of clear-water pier and abutment scour. J. Hydraul. Eng., ASCE, 128:811-820.

10)    Raudkivi, A. J., Ettema, R. 1983. Clear-water scour at cylindrical piers. Journal of Hydraulic Engineering, ASCE, 109(3): 338-350.

11)    Setia, B. and Verma, D. (2007),Physics of Flow Mechanism of Scour Around Submerged Pipelines on anErodible Bed, 3rd WSEAS International Conference on Applied and Theoretical Mechanics, Spain, December 14-16.

12)    Tregnaghi, M., Marion, A., and Gaudio, R. (2007). "Affinity and similarity of local scour holes at bed sills."Water Resource. Res., 43(11), W11417.

13)    Neil, C. R. 1973. Guide to Bridge Hydraulics. Road and Transportation Association of Canada, University of Toronto, Canada.

14)    Yang, L., Guo, Y., Shi, B., Kuang, C., Xu, W. and Cao, S., (2012), Study of Scour around Submarine Pipeline with a Rubber Plate or Rigid Spoiler in Wave Conditions, Journal of Waterway, Port, Coastal and Ocean Engineering, 138(6), p. 484-490.

15)    Zhao, E., Shi, B., Q, U,K., Dong, W and Zhang, J,(2018),Experimental and Numerical Investigation of Local Scour AroundSubmarine Piggyback Pipeline Under Steady Current.Journal of Ocean University of China; Apr2018, Vol. 17 Issue 2, p244-256, 13p.

16)    Zhu, H., Qi, X., Lin, P., and Yang, Y., (2013),Numerical simulation of flow around a submarine pipe with a spoiler and current-induced scour beneath the pipe, Journal of Applied Ocean Research, 41, p. 87-100.