نوع مقاله : مقاله پژوهشی
1 دانشجوی کارشناسی ارشد /مهندسی عمران آب - دانشگاه تربیت مدرس
2 دانشیار /سازه های هیدرولیکی- دانشگاه تربیت مدرس
عنوان مقاله [English]
In this research, using complete form of Navier-Stokes equations, the 3-D turbulent flow pattern in a 180-degree river bend is simulated. The k-e and k-w turbulence models are used to close the system of equations and modeling Reynolds stresses. Equations are solved numerically using FVM method as implemented in the commercial code FLUENT. Experimental results in a 180-degree bend in Tarbiat Modarres Hydraulic lab (MHL) are used to verify the numerical results. Simulation showed that both of turbulence models accurately predicted the flow pattern in this bend. The prediction accuracy of the k-w model, especially in the outlet region of the bend, is however higher than the k-e model. The results of first model showed that as the experimental model, there are two secondary flow cells in the q =180° cross section but the k-e model predicted only one cell. Distribution of bed and side wall shear stresses showed that there are two probable scouring regions in two halves of the bend. Previous experimental investigations with mobile bed models confirm these results.