11939

10952

كارشناسي ارشد

آب و سازه هاي هيدروليكي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده عمران

1395

پنج، 41ص.: مصور، جدول، نمودار

ص. ع. به فارسي و انگليسي

محمدرضا چمني، محمد نويد مقيم

محمد كريم بيرامي

عبدالرضا كبيري ساماني، احمد شانه ساز زاده

1395/09/30

كتابنامه

عمران

مهندسي عمران

ID10952

Characteristics of A type hydraulic jump at a positive step Milad Mohammadi Milad mohammadi@cv iut ac ir September 21 2016 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisors Dr Mohammad Reza Chamani mchamani@cc iut ac ir Dr Mohammad Navid Moghim moghim@cc iut ac ir AbstractThe current thesis aims to study the characteristics of the A type hydraulic jump at a positive step Thecurrent research is divided into three parts The first part aims to present a model that accurately evaluate theconjugate flow depth of the A type hydraulic jump at a positive step A relation is given to estimate the smallrise of the flow at the step Assuming the flow at the step as a concave curvilinear flow a non linear pressuredistribution is considered Applying one dimensional momentum equation in the flow direction anexpression for the conjugate flow depth in terms of initial Froud number and step height is presented In thesecond part two approaches are presented to evaluate the length of the A type jump In the first approach theend of the A type hydraulic jump is assumed to be at a short distance downstream of the step brink and thehydraulic jump is modeled as a turbulent wall jet Knowing that the pressure gradient is the only differencebetween the hydraulic jump and the wall jet pressure gradient is taken into account as an effectiveparameter Using dimensional analysis an expression for the maximum velocity of the wall jet is extracted Applying appropriate expressions for the velocity distribution and the growth rate of the jump the jumplength is expressed in terms of the initial Froud number In the second approach the end of the jump isassumed to locate at the step brink and the jump length is calculated by the revised Beirami Chamani relationfor the classic jump In the final part the efficiency of the model is detected from the energy dissipationperspective The results confirm the efficiency of the theory of curvilinear flow to estimate the conjugate flow depth The accuracy of the predictions decreases as the Froud number increases and the relative step heightdecreses The conjugate flow depth increases with initial Froud number with an approximate linear trend andwith a slope of almost unity It is concluded that predictions of the jump length by the first approach arealways higher than experimental data and this approach is is not applicable at low Froud numbers Thesecond approach estimates the jump length accurately in which the jump length increases sharply with initialFroud number and then decreases mildly Despite common belief existence of a positive step against has noconsiderable effect on the energy dissipation rate of the jump Key WordsHydraulic jump Positive step Conjugate flow depth Curvilinear flow Jump length turbulent wall jet Pressure gradient Energy dissipation

محمدرضا چمني، محمد نويد مقيم

محمد كريم بيرامي

عبدالرضا كبيري ساماني، احمد شانه ساز زاده