6659

6210

كارشناسي ارشد

آبياري و زهكشي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي

1390

سيزده، 113ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

منوچهر حيدرپور، حسين افضلي مهر

حسن طباطبائي

12/2/91

سعيد اسلاميان، سعيد سلطاني

1396/10/06

كتابنامه

كشاورزي

مهندسي كشاورزي

ID6210

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Investigation of Transverse Mixing Coefficient Distribution of Velocity and Turbulence Intencity in Precence of Dunes and Vegetation Mahboobe Ghasemi Zaniani mq en2009@gmail com Date of Submission 25 12 2011 Department of Water Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Manouchehr Heidarpour Heidar@cc iut ac ir Hossein Afzali Mehr Hafzali@cc iut ac irAbstract The importance of the rivers in meeting human needs and also growing pollution of surface waters studying of mixing processes for recycling contaminated water could be important for management ofresources Due to importance of bed form such as dunes and also vegetation in rivers channels andstreams the Study of pollutant mixing coefficient on the interaction of Dune and vegetation is moreimportant than before The purpose of this study is to investigate transverse mixing coefficient andstructure of flow on dunes in the presence of vegetation in walls To check mixing coefficient experimental measurements were made over fifth to ninth dunes in a series of ten of 2 dimensionalasymmetric gravel dunes in two cases with and without vegetated walls The dunes had an angle of leeslope of 28 a mean wavelength of 1 m and two mean height of 0 04 and 0 08 m The banks of the flumewere covered by rice stems with median diameter of 2 7 mm and stem density was calculated 400 stem m The used sand for construction of dunes had the mean diameter of 14mm to investigate the effect ofaspect ratio on transverse mixing coefficient five flow depths were used in two cases with and withoutvegetation on walls Concentration data in five sections by EC meter at the downstream of the injectionsite were taken 27 samples of concentration were taken at each sampling section To investigate ofstructure flow on dunes samples of velocity at 14 sections were taken The results show that dunes areimportance in increasing transverse mixing coefficient to the extent that this coefficient in presence ofdunes is 2 36 more than that on flat bed and increasing height of dunes makes this value be 3 19 moretimes than that on flat bed Despite the increase in the transverse mixing coefficient due to interaction ofDune and vegetation the effect of vegetation on this coefficient is less than that of Dune Due to theconstant channel width in both cases with and without vegetation with increasing aspect ratio secondarycurrents become weaker and transverse mixing coefficient decreases Length of complete mixing is alsoreduced with increasing depth However when the be is flat the distance the tracer needs to go along thechannel should be 35 meter in order to complete mixing can be achieved This length on dunes with twoheights of 4 and 8 cm is equal to 10 and 11 meters respectively that is 1 3 that on flat bed Increasingheight of dune transfer flow separation zone from nearness of crest of dune with height of 4cm todownstream of lee slope for dune with height of 8cm Increasing height of crest of dune due to themaximum stress occurs farther from the bed The maximum turbulence intensity on dunes with height of8cm occurred at top of separation zone in wake region and was 0 1 m s With decreasing height of dune maximum intensity of turbulence decreased and reached 0 0898 m s on stoss lee Key words Transverse mixing coefficient beds form dunes flow structure Vegetation aspect ratio separation zone

منوچهر حيدرپور، حسين افضلي مهر

حسن طباطبائي

سعيد اسلاميان، سعيد سلطاني