3879

3662

كارشناسي ارشد

آبياري وزهكشي

اصفهان: دانشگاه صنعتي اصفهان،دانشكده كشاورزي

1386

دوازده، 238،[II]ص: مصور، جدول، نمودار

ص.ع به: فارسي وانگليسي

حسين افضلي مهر

چيويي منگ، حسين سقاييان نژاد

8/2/87

منوچهرحيدر پور، محمد علي حاج عباسي

مهندسي كشاورزي

ID3662

به فارسي وانگليسي: قابل رويت در نسخه ديجيتال

AbstractApproaching flow to bed forms and hydraulic structures can be appeared as acceleratingor decelerating in rivers and natural channels Knowledge of incipient motion in non uniform flows can greatly influence on scouring and resistance to flow in rivers Theobjective of this research is to study the turbulent flow characteristics on the threshold ofmotion in non uniform flows The experiments were carried out in Hydraulic Modelinglaboratory of Nanyang Technological university in a 14 m long 0 6 m wide and 0 6 m deep flume using three sets of uniform sediment with median grain sizes of D50 1 8 1 3 0 8 mm and 8 slopes of 0 007 0 009 0 0125 0 015 under non uniformflows Turbulent flow characteristics and velocity components were measured in threedifferent cross sections 5 7 and 9 meters from the flume entrance by an AcousticDoppler Velocimeter ADV Obtained data from 76 velocity profiles was analyzed andfiltered by WinADV software and the Reynolds stresses under different sedimentparticles and bed slopes were investigated The results showed that the velocitydistribution and the normal and shear stresses are affected by weakly mobile bedconditions The critical shields parameter was smaller in decelerating flow in comparisonto the accelerating flow due to higher normal and shear stresses near the bed in formercase The results of this study also revealed that the incipient motion in non uniformflows depends on acceleration and deceleration bed slope and relative depth

حسين افضلي مهر

چيويي منگ، حسين سقاييان نژاد

منوچهرحيدر پور، محمد علي حاج عباسي