نوع مقاله : مقاله کامل پژوهشی
دانشکدۀ فنی و مهندسی، دانشگاه خوارزمی تهران
عنوان مقاله [English]
Spur dikes are common river training structures. Spur dikes deviate approaching flow to the far bank. The scour formation around the spur dikes may be used to increase the habitants.
Many researches such as Khosravi-Mashizi (2011) were done to find the effect of different effective parameters on scour hole dimensions around spur dikes. Previous researches showed that the scour hole dimensions decreases with spur dike submergence (Shariatzadeh, 2011). Previous researches on flow field around the spur dike may be categorized into two groups. The first group of researchers worked on mean flowfield and streamlines (Fazli, 2008). The researchers reported the formation of the upstream downflow and a horseshoe vortex around the spur dikes. The secondary flow has a main role in scour hole formation and the maximum strength of the secondary flow occurs near the upstream tip of the spur dike. In the second group of researches, the flowfield was investigated based on turbulent flow parameters (Dey and Barbhuiya, 2006). Researchers tried to investigate the relation between the scour and flow fields using turbulent parameters such as quadrant analysis, triple correlations and turbulent kinetic energy fluxes. The researchers showed that the ejection and sweep events have main role on sediment entrainment. According to the best knowledge of the authors, flow field investigation around the spur dike and the comparsion between the flow structures around the straight and T shaped spur dikes are in the preliminary stages. Hence, the authors tried to study and compare the flow structures around a straight and T shaped spur dike using spectral analysis, statistics parameters and conditional averaged velocity to find the effect of the turbulent parameters on scour process around the spur dikes.