7049

6591

كارشناسي ارشد

آبياري و زهكشي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي

1390

دوازده، 116ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

منوچهر حيدرپور، حسين افضلي مهر

اسماعيل لندي، حسين سقائيان نژاد

16/7/91

جهانگير عابدي، جليل رضوي

1396/09/19

كتابنامه

كشاورزي

مهندسي كشاورزي

ID6591

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Investigation of Flow Structure Effect on Local Scour at Cylindrical Group Piers Maryam Ranjkesh ranjkesh maryam@yahoo com 25 02 2012 Department of Water Engineering Collage of Agriculture Isfahan University of Technology Isfahan84156 83111 Iran Degree M Sc Language FarsiManouchehr Heidarpour heidar@cc iut ac irHossein Afzalimehr hafzali@cc iut ac irAbstractThe occurrence and development of scour hole around bridge pier are main causes of bridge destruction Thefirst step to solve this problem is investigation of flow pattern and recognition of scour process around bridgepier The prediction of occurrence development and final situation of scour hole around pier is the mostimportant in the hydraulic design of bridges Although the flow pattern around a single pier has been widelyinvestigated there are few studies around pier groups Moreover the scour hole around group pier is affectedby factors which are not valid for single pier The present study contains results of the experiments on the flowpattern around two and three circular piers situated in a line arrangement measured by an Acoustic DopplerVelocimeter ADV under a clear water scour condition These group piers were tested with s b 4 6 and 8 and compared with single pier Laboratory flume experimental detection were made by using ADV todetermine velocity Reynolds stress distribution and turbulent intensities Experiments were carried out in ahorizontal re circulating flume in the Hydraulic Laboratory at the Isfahan University of Technology in Iran The flume had 8 m long 0 4 m wide and 0 6 m deep Uniformity graded sand of a median diameter d of0 71 mm and the geometric standard deviation 1 2 was applied Scour hole waz frozen by cement to facilitateperformance of the experiments Results of this experiments indicated that in group of two piers during theexperiment scour depth of first pier is greater than that of the single pier due to the reinforcing effect andbecause of sheltering effect scour depth of the second pier is less than that of the the single pier In group ofthree piers the scour depth of the second pier is equal to the single pier due to the interaction of reinforcingand sheltering effect and the equilibrium scour depth for the first and the third piers is equal to front and rearpier in group of two piers respectively By increasing of space between piers reinforcing and shelteringeffects reducing In upstream the velocity profiles and turbulent intensities showed that the existence ofprimary vortex associated with down flow inside the scour hole and in downstream wake vortex causedirregularities in flow pattern In the upstream and scour hole continuity to 7 6 cm distance from the up stream the values of velocity component in x direction were negative which indicated the flow separation Whereas in the down stream negative value of u were observed just in rear pier and in surface water The RMS u and u velocity profiles showed that osilliatons of u velocity in rear pier causes the u velocity reduces in this region and wake wortex is the main factor for osilliation of u velocity root mean square u The values of root meansquare u in front of second and third piers are distance between different space of piers and clearly indicatedthat root mean square u in 4b and 6b spaces are greater than that 6b and 8b spaces respectively Key words scouring bridge pier group piers flow pattern

منوچهر حيدرپور، حسين افضلي مهر

اسماعيل لندي، حسين سقائيان نژاد

جهانگير عابدي، جليل رضوي