Document Type : Research Paper

Authors

1 M. Sc. Alumni, Department of Naval Architecture and Marine Engineering, Faculty of Marine Engineering, Khorramshahr University of Marine Science and Technology, Khorramshahr, Iran

2 Assist. Professor, Department of Naval Architecture and Marine Engineering, Faculty of Marine Engineering, Khorramshahr University of Marine Science and Technology, Khorramshahr, Iran

Abstract

In order to protect the bank and prevent their erosion spur dike is used. Importance of these structures in the bend is more, because of secondary flows and consequently bank erosion. In this paper the flow pattern around series of vertical spure dikes in the 90° bend is investigated by a 3D RANS solver. In order to simulate the complex behavior of free surface and turbulent flow the volume of fluid method and realizable k-ɛ closure have been used, respectively. Two lengths spure dike (equal to 15 and 25 percent of width), two spacing (3 and 5 three times the length) and two depths (3 and 5cm) in constant discharge 25 lit/s in the mild bend flume with width 0.7m and depth 0.12 m has been examined. Comparison among the results with experimental data shows good agreement among them. Also, the results illustrate spure dike deviations maximum velocity to the inner bank in entrance of bend and then deviations to the middle flume. Increasing the length of the spure dikes increases the velocity but it has no effect on the location of the maximum velocity as in all arrangement occurrence in 71 to 81 degree of bend. In the case of shear stress, the maximum value is in the range of 71 to 81˚.

Keywords

Main Subjects

Abbasi S., Pourshahbaz H. and Taghvai, P. (2019). Investigation of bed morphological variation in channels with a group of parallel unequal spur dike in various orientations. Irrig. water Eng. J.,9(35), 38-48.
Ahli Y., Bakhtiari M. and Moore M. (2018). Numerical investigation velocity and shear stress in a 90 ̊ degree mild bend. Hydrophys. J., 4(2), 59-73.
Arman A., Fatahi P. and Zahiri J. (2017). Simulation of flow and sediment pattern with spurdikes series in a 90 degree mild bend using CCHE2D model. J. Water Soil Conserv., 24(3), 21-39 [In Persian].
Bakhtiari M., Kashefipour S., Ghomeshi M. and Zahiri J. (2012). Effect of geometric parameters of spur dike and depth-placed riprap on its failure threshold in a 90 flume bend. Ecol. Environ. Conserv., 4, 479-484.
CD Adapco, (2017). STAR CCM+ User's Guide Version 12.04.010.
Duan J. G., He L., Fu X. and Wang Q. (2009). Mean flow and turbulence around experimental spur dike. Adv. Water Resour., 32(12), 1717-1725.
Ghodsian M. and Vaghefi M. (2009). Experimental study on scour and flow field in a scour hole around a T-shape spur dike in a 90 bend. Int. J. Sediment Res., 24(2), 145-158.
Giglou A. N., Mccorquodale J. A. and Solari L. (2018). Numerical study on the effect of the spur dikes on sedimentation pattern. Ain Shams Eng. J., 9(4), 2057-2066.
Giri S., Shimizu Y. and Surajate B. (2004). Laboratory measurement and numerical simulation of flow and turbulence in a meandering-like flume with spurs. Flow Measure. Instrum., 15(5-6), 301-309.
Huang S. l., Jia Y. F., Hsun-Chuan C. and Sam S. (2009). Three-dimensional numerical modeling of secondary flows in a wide curved channel. J. Hydrodyn., Ser. B, 21(6), 758-766.
Ramamurthy A., Han S. and Biron P. (2013). Three-dimensional simulation parameters for 90 open channel bend flows. J. Comput. Civil Eng., 27(3), 282-291.
Roache P. J. (1997). Quantification of uncertainty in computational fluid dynamics. Annual Rev. Fluid Mechanic., 29(1), 123-160.
Shaker E., Kashefipour S. and Shafai Bajestan M. (2014). Experimental investigation on the influence of some unsteady flow parameters on bed scour under the pipeline crossing across the current experimental investigation on the influence of some unsteady flow parameters on bed scour under the pipeline crossing across the current. J. Water Soil Sci., 23(4), 83-98.
Vaghefi M., Shakerdargah M., Fiouz A. and Akbari M. (2014). Numerical Investigation of the effect of Froude number on flow pattern around a single T-shaped spur dike in a bend channel. Int. J. Eng. Res., 3(5), 351-355.
Yazdi J., Sarkardeh H., Azamathulla H. M. and Ghani A. A. (2010). 3D simulation of flow around a single spur dike with free-surface flow. Intl. J. River Basin Manage., 8(1), 55-62.
Zhang M. l. and Shen Y. M. (2008). Three-dimensional simulation of meandering river based on 3-D RNG k-ε turbulence model. J. Hydrodyn., 20(4), 448-455.