بررسي آزمايشگاهي الگوي جريان كمي اطراف آبشكن T شكل در قوس 90 درجه با بستر صلب

Experimental Study on Flow Pattern Quantities around T Shaped Spur Dike in a 90 Degree Bend

Spur dike is a hydraulic structure used for protection of river banks. In the past few decades, the use of spur dikes for stability of the outer banks of rivers has attracted the attention of hydraulic engineers. This study experimentally measures the 3D flow field in the 90 degree bend with T-shaped spur dike in section 75-degree. The experiments were carried out in a channel with a 90 degrees bend. The three-dimensional Acoustic Doppler Velocimeter (ADV) was used for measuring the flow field. The three-dimensional time-averaged velocity in the 90-degree bend with spur dike was measured. Then the comparison of the three dimensional components of velocity was made in different sections and the differences of the flow pattern along the bend was analyzed. The observations showed the effect of the spur dike on the secondary flow patterns and in the formation of the subsequent secondary flows. Some horizontal vortices with a counter-clock-wise direction were also be observed in the up and down stream of the spur dike near the outer bank. In addition, the vortices and reverse flows in the up and down stream of the spur dike as well as the changes in the longitudinal, lateral and vertical velocity components are investigated in this study.