Local Scour Around Non-Submerged Bell Mouth Groin

Year 2011, Volume: 3 Issue: 2, 37 - 51, 01.06.2011

M.j. Uddin M.m. Hossain

Abstract

Groins are the most popular techniques for riverbank stabilization that are constructed along the channel bank to locally
change river conditions, thereby creating a flow condition that promotes navigability and diverts the flow away from the bank.
The scour around groin head play a very important for their performance. No systematic experiments have been conducted to
study the scour around bell mouth groin. An experimental study was undertaken in a 45.6m long and 2.45m wide laboratory
water basin to investigate the local scour around a non-submerged bell-mouth groin structure. A total number of 12 test runs
were performed for different flow conditions. Three different discharges and four different angles with non-submerged groin
condition were considered in the present study. Therefore, Twelve tests were conducted of which six had a water depth of 14 cm
and the rest six had a flow depth of 18 cm. All tests were conducted for 8 hours duration in clear water condition. In order to
avoid the ripple formation, the coarse sand with d50 = 0.75 mm was selected as bed material. Scour depth for 90ο
angled groin
was observed to be the maximum and for 135ο
it was the minimum. The time to reach maximum scour depth was found to vary
with discharge and angle of attack. The study also revealed that maximum scour depth and deposition pattern changed for the
case of different test runs. Scour depth varied with velocity variation of flow, and an increasing tendency of scour depth has
been observed with increasing flow intensity. Maximum scour depth shows an increasing trend with increasing Froude
number.

Keywords

Local Scour, Non-Submerged Groin, Bell Mouth Groin

References

• [1] Anwaruzzaman, S.M. (1998). “Evaluation of Selected Local Scour Formulae Around Piers and Groynes.” M.Engg. Thesis, Department of Water Resources Engg., BUET, Dhaka.
• [2] Ahmad M (1953). “Experiments on design and behavior of spur-dikes.” Proc. Int. Hydraul. Convention. : 145–159
• [3] Chang, H.H. (1988). “Fluvial Processes in River Engineering.” John Wiley and Sons Inc., USA.
• [4] Gill M. A. (1972). “Erosion of sand beds around spur-dikes.” J. Hydraul. Div., Am. Soc. Civ. Eng. 98: 1587–1602
• [5] Garde, R. J., Subramanya, K., Nambudripad, K. D. (1961). Study of scour around spur dikes. ASCE Journal of the Hydraulics Division, 87(HY6), 23-37.
• [6] Hossain, M.M. (1981). “Study of River Bank Stabilization in a Bend by Groin.” M.Sc. thesis, BUET, Dhaka, Bangladesh.
• [7] Hasan, R.M.M. (2003). “Experimental Study of Local Scour at the Toe of Protected Embankment.” M.Engg. Thesis, Department of Water Resources Engg., BUET, Dhaka.
• [8] Islam, G.M.T., Rahman, M.M., and Haque, M.A. (2002). “Experimental Study on Scour around Groins in a Straight Compound Channel.” IWFM, BUET, Dhaka.
• [9] Ishigaki, T. and Baba, Y. (2004). “Local Scour Induced by 3D Flow around Attracting and Deflecting Groins.” Proceedings of Second International Conference on Scour and Erosion, Meritus Mandarin, Singapore: 301-308.
• [10] Khan, M.A.O. (1983). “An Experimental Investigation on the Effect of Location and Projection of Single Groin in a Bend.” M.Sc. Thesis, Department of Water Resources Engg., BUET, Dhaka.
• [11] Khaleduzzaman, A.T.M. (2004). “Experimental Study on River Course Stabilization and Restoration by using Groin-like Structures.” Master thesis Kyoto University, Japan.
• [12] Kabir, M.A. (2007). “An Experimental Study on the Effect of Submerged Vane on Scour and Flow around Abutment.” M.Sc. Thesis, Department of Water Resources Engg., BUET, Dhaka.
• [13] Khatun, F. (2001). “Experimental Study on Local Scour around Bridge Piers and Its Reduction.” M.Sc.Thesis, Department of Water Resources Engineering, BUET, Dhaka.
• [14] Kuhnle, R.A., Alonso, C.V., Shields, F. D. (2002). “Local scour associated with angled spur dikes.” Journal of Hydraulic Engineering, ASCE, Vol. 128(12), pp. 1087-1093.
• [15] Kuhnle, R. A.; Alonso, C.V., Shields, F.D. (1999). “Geometry of scour holes associated with 90-degree spur dikes.” J. Hydraulic Engineering. ASCE, Vol. 125 (9), p.972.
• [16] Laursen E.M. (1963). “An analysis of relief bridge scour.” J. Hydraul. Div., Am. Soc. Civ. Eng. 89: 93–118
• [17] Liu, M. K., Chang, F. M., Skinner, M. M. (1961). Effect of bridge construction on scour and backwater. Report No. CER60-HKL22, Department of Civil Engineering, Colorado State University, Fort Collins, Colorado.
• [18] Muto, Y., Kitamura, K., Baba, Y. and Nakagawa, H. (2005). “Field Measurement of Velocity Distribution in Groin Fields with ADCP.” Annual Journal of Hydraulic Engineering, JSCE, 49.
• [19] Melville, B.W. (1997). “Pier and abutment scour: integrated approach.” Journal of Hydraulic Engineering, ASCE, 123(2), 125-136.
• [20] Melville, B.W. (1992). “Local Scour at Bridge Abutments.” ASCE Journal of Hydraulic Engineering, Vol. 118, No. 4, April, 1992, pg615.
• [21] Rahman, M.M. and Muramoto, Y. (1999). “Prediction of Maximum Scour Depth around Spur-Dike-Like Structures.” Annual Journal of Hydraulic Engineering, JSCE, 43: 623-628
• [22] Rahman, M.M., Haque, M.A. and Alam, A.A. (2001). “Flow Field Around Piers and Abutments at the Initiation of Scouring.” Proceedings of the 1st International Conference on Civil Engineering, IEB and FEISCA, Chittagong, 2-3 Nov. pp.403-410.
• [23] Rahman, M.M., Haque, M.A. and Islam, M.S. (2002). “Flow and Scouring around Piers and Abutments.” 13th IAHR-APD Congress, Singapore, 280-283.
• [24] Raudkivi, A.J. and Ettema, R. (1977). “Effects of Sediment Gradation on Clear Water Scour.” Journal of Hydraulic Engineering, ASCE, 103(10), 1209-1212.
• [25] Rajaratnam N, Nwachukwu B A (1983). “Flow near groin-like structures.” J. Hydraul. Eng., Am. Soc. Civ.Eng. 109: 463–480
• [26] Richardson, E.V., Simons, D.B., Karaki, S., Mahmood, K., and Stevens, M.A., (1975) “Highways in river environment.” Hydraulic and Environmental Design Considerations, Engineering Research Center, Colorado State University, Fort Collins, Co.
• [27] Shields Jr., F.D., Cooper, C.M. and Knight S.S. (1995). “ Experiment in Stream Restoration.” Journal of Hydraulic Engineering, ASCE, 121(6): 494-502.
• [28] Sarker, M.S.R. (2001). “Development of a Physical Model Facility and Investigation of Flow Pattern Due to Groyne on the Right Bank of Jumuna River near Kazirhat-Natibpur Area.” M.Sc. Thesis, Department of Water Resources Engineering, BUET, Dhaka.
• [29] Uijttewaal, W.S.J., Lehman, D., and van Mazijk, A. (2001). “Exchange Process Between a River and Its Groin Fields: Model Experiment.” Journal of Hydraulic Engineering, Vol. 127, No 11, pp.122-125.
• [30] Zhang, H. (2005). “Flow and Bed Evolution in Channels with Spur Dykes.” Doctoral Thesis, Kyoto University, Japan.
• [31] Zhang, H., Nakagawa, H., Ishigaki, T., Muto, Y., and Khaleduzzaman, A.T.M. (2005) “Flow and Bed Deformation around a series of Impermeable and Permeable Spur Dykes.” Proc. of the International Conference on Monitoring, Prediction & Mitigation of Water-Related Disasters (MPMD) Jan. 12-15, Kyoto, pp.197-202