3257

3166

كارشناسي ارشد

﴿ آبياري و زهكشي ﴾

اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي

1384

سيزده، 148، [II]ص.: مصور، جدول، نمودار

ص. ع. به فارسي و انگليسي

حسين افضلي مهر

اسماعيل لندي، محمد علي طرفه

منوچهر حيدر پور، افشين هنر بخش

1396/02/30

كتابنامه

كشاورزي

مهندسي كشاورزي

ID3166

به فارسي و انگليسي : قابل رو يت در نسخه ديجيتالي

AbstractFlow resistance is often one of the most important subjects required for hydrauliccomputations and designs The existing methods to estimate the resistance coefficientshave been developed for uniform flow and small grain size streams Using the methodsfor non uniform flow conditions can be led to considerable error in the determination ofresistance to flow This research investigates flow resistance in channels with cobble onbed and vegetation on sides Accordingly geometric and hydraulic characteristics of non uniform flow and intermediate roughness scale were measured in two case of with andwithout plant For the first case three reaches were selected in around of Khansar Forthe second case two reaches were selected one reach sited in old channels and the otherreach from Marbore River in Koohrang Validation of the logarithmic and the parabolicvelocity distribution laws has investigated using measured velocity profiles in this study Results showed that the logarithmic law is valid for the entire reaches however theparabolic law isn t valid for reaches with plant on sides In addition shear velocity whichis a vital factor in predicting flow resistance was calculated from three methods thelogarithmic the boundary layer characteristics and the simplified St Venant equation Comparison of these methods showed that the logarithmic method estimation wassensitive to determination of reference level Also St Venant equation is very sensitive todetermination of bed and friction slopes Therefore the both methods aren trecommended for this study Finally the boundary layer characteristics method issuggested for estimation of shear velocity in coarse bed channels with vegetation onsides In reaches which were without plant using nonlinear regression through SASsoftware a formula was developed for estimation of flow resistance in intermediateroughness scales In this formula aspect ratio roughness ratio and parameter of particleincipient motion have significant influence on flow resistance prediction But assessmentof reaches with plant on sides showed that available parameters aren t adequate forrealization of flow resistance This case request further investigations to improve ourunderstanding from interaction of plant and cobble on flow resistance

حسين افضلي مهر

اسماعيل لندي، محمد علي طرفه

منوچهر حيدر پور، افشين هنر بخش