نوع مقاله : پژوهشی
نویسندگان
1 دانشکده مهندسی عمران و محیط زیست، دانشگاه تربیت مدرس
2 دانشکده مهندسی عمران، دانشگاه خلیج فارس
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Spur dikes are hydraulic structures that are used to protect river banks. In this paper, parameters influencing flow pattern around non-submerged attracting series of T- head spur dikes in straight channel are investigated. Evaluating of the flow pattern indicates that using spur dikes causes reversed flow and increasing the horizontal and vertical components of velocity at upstream of
spur dikes. Longitudinal component of velocities at the front of the first spur dike wing is more than longitudinal velocities in the front of the second and third spur dike wing and in front of the second spur dike wing is more than third spur dike wing. The horizontal component of velocity are maximum the surface near to bed in reversed flow region and the negative transvers velocities of reversed flow are maximum near the free surface between spur dikes and in the front of the second and third spur dike wing. The deep positive velocities are seen in the edge of wing upstream of first spur dike and between spur dikes. Investigation of turbulence kinetic energy in flow pattern shows that it is maximum in the edge of wing upstream of first spur dike and has increased in wing of spur dikes' shear layer. Investigation of Reynolds stresses in flow pattern shows that component $-{\rho u_{i}^{'}}{\nu_{i}^{'}}$ is maximum compared to two other components and the maximum value of that is occurred in the downstream and among of spur dikes. The maximum value of $-{\rho u_{i}^{'}}{\nu_{i}^{'}}$ component is respectively about 5 and 6 times the values of $-{\rho u_{i}^{'}}{w_{i}^{'}}$ and $-{\rho \nu_{i}^{'}}{w_{i}^{'}}$ components. Component $-{\rho u_{i}^{'}}{w_{i}^{'}}$is at minimum compared to two other components and component $-{\rho \nu_{i}^{'}}{w_{i}^{'}}$ at the edge of wing upstream of spur dikes and the minimum value of that occurs in the downstream and among of spur dikes. Investigation of bed shear stress shows that the maximum of bed shear has occurred at the edge of wing upstream of the first spur dike.
کلیدواژهها [English]
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