15132

13610

كارشناسي ارشد

آب و سازه هاي هيدروليكي

اصفهان : دانشگاه صنعتي اصفهان

1398

هفده، 112ص.: مصور، جدول، نمودار

محمدرضا چمني، محمدنويد مقيم

عبدالرضا كبيري ساماني، محمود فغفور مغربي

1398/07/13

كتابنامه

مهندسي عمران

مهندسي عمران

1398/07/13

2566130

Flow patterns of scour around the cone bridge piers Farnaz Meshkinfar f meshkinfar@cv iut ac ir Data of Submission 2019 6 18 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisors Mohammad Reaz Chamani @cc iut ac ir Mohammad Navid Moghim moghim@cc iut ac irAbstractScour is a phenomenon which occurs as a result of bed erosion Local scouring is special typeof the scour which is considered as one of the main reasons of bridges failure Identifyingdifferent features of flow patterns around the pier is a necessary condition to understand thescour mechanism Although there are many studies which have been conducted to explore thedepth of scouring around cylindrical and cone piers the flow patterns around the cone piershave not been studied adequately The present study explores the flow patterns around the cylindrical and cone piers Experiments have been carried out for two cases of the flat bed before scouring and theequilibrium scour Cone and cylindrical piers with diameters of 60 and 70 mm were usedwith discharges of 43 and 29 L s The side angle of the cone pier was set at 2 5 and 5 degrees The experiments were done in a channel with the length of 9 m width of 0 6 m and height of0 7 m Sand particles of diameter 0 74 mm were placed at channel bed Measurement ofinstantaneous velocity was done in the central axis of the channel upstream and downstreamof the pier with 3D Acoustic Doppler Velocimeter ADV The channel bed was fixed bycement and stone powder to facilitate the measurement of the velocity field Results of the experiments indicate that the cone pier decreases vertical and longitudinalvelocities at the upstream of the pier As the side angle of the cone pier increases the extentof scour hole is reduced and the values of longitudinal velocity decrease as well Theupstream longitudinal velocity profile of the cone pier is more uniform than the cylindricalpier As a result the downward pressure gradient reduces and consequently the downflowstrength in the vertical plane reduces The maximum values of the vertical velocity near thepier upstream decrease as the side angle of the cone pier increases The values of longitudinaland vertical velocity are not significantly different for both cone and cylindrical piers atdownstream The maximum values of vertical velocity slightly decrease as the side angleincreases Keywords Scouring flow patterns bridge pier cylindrical pier cone pier

محمدرضا چمني، محمدنويد مقيم

عبدالرضا كبيري ساماني، محمود فغفور مغربي