7050

6592

كارشناسي ارشد

آبياري و زهكشي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي

1390

شانزده، 173ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

حسين افضلي مهر، منوچهر حيدرپور

اسماعيل لندي، حسين سقائيان نژاد

16/7/91

جهانگير عابدي، سعيد سلطاني

1396/09/19

كتابنامه

كشاورزي

مهندسي كشاورزي

ID6592

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Investigation Geometric Shape and Vegetation Cover on AbutmentScouring Somayeh Bakhshi Sbakhshi88@yahoo com 2012 02 20 Department of Water Engineering Collage of Agriculture Isfahan University of Technology Isfahan84156 83111 Iran Degree M Sc Language FarsiHossein Afzalimehr hafzali@cc iut ac irManouchehr Heidarpour heidar@cc iut irAbstractFailure of bridges due to scour at abutments is a common occurrence Also vegetation exists widely in naturalriver system especially in flood plain Investigation of shape and vegetation cover on flow structure inabutment scouring is the main goals of this study So laboratory flume experimental detection were made byusing Acoustic Doppler Velocimeter ADV to determine velocity Reynolds stress distribution and turbulentintensities in four runs 1 vertical wall abutment 2 wing wall abutment 3 wing wall abutment with circulateedge 4 wing wall abutment with circulate edge and vegetated bank Experiments were carried out in ahorizontal re circulating flume in the Hydraulic Laboratory at the Isfahan University of Technology in Iran The flume had 7 m long 0 33 m wide and 0 36 m deep Uniformly graded sand of a median diameter d of0 71 mm with the geometric standard deviation 1 2 was applied in this study The rice stems with a mediandiameter of 2 7mm were used to simulate vegetation on the flume walls In upstream the time averagedvelocity vector and turbulent intensities show the existence of primary vortex associated with down flowinside the scour hole and in downstream the flow field is essentially ill defined comprising irregularities dueto the vortex shedding Also results reveal scouring depth and equilibrium time decrease 25 and 32 respectively from vertical wall abutment to wing wall abutment run These results have been happened as aresult of stronger primary vortex in vertical wall abutment in comparison with wing wall abutment the otherrun of this study compare flow structure in scouring hole around a wing wall abutment with circulate edge forthe vegetated and bare banks over a sand bed flume Results reveal that the vegetated banks in a flumechanged the process of scouring as well as incipient motion of particles decreasing the equilibrium time andscouring depth considerably Comparison of bare banks and vegetated banks showed that the equilibrium timeand scouring depth were reduced from 20 hours to 9 hours and from 8 4 cm to 3 2 cm respectively Vegetation increases the stream wise velocity at the central line of flume and decreases it near the banks causing a larger velocity gradient and faster movement of particles in compared with bare banks run Also investigation of velocity profiles and turbulent intensities at the upstream of abutment with vegetation coveron the flume walls shows that primary vortex decreases at upstream of abutment but the effect of vortex indownstream has not changed Key words scouring cover vegetation abutment wing wall abutment wing wall abutment with circulatededge vertical wall abutment

حسين افضلي مهر، منوچهر حيدرپور

اسماعيل لندي، حسين سقائيان نژاد

جهانگير عابدي، سعيد سلطاني