Numerical Modelling of Flow Field in Skewed Compound Channel with Inclined Floodplains

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: Numerical Modelling of Flow Field in Skewed Compound Channel with Inclined Floodplains

ارائه دهنده: Provider: Farshid Karimi

اساتید راهنما: Supervisors: Dr Bahram Rezaei

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: Dr Majid Fazli , Dr Jalal Sadeghiyan

زمان و تاریخ ارائه: Time and date of presentation: 2022/10/09

مکان ارائه: Place of presentation: Seminar 2nd

چکیده: Abstract: Simulation of flow field in compound channels or rivers is one of the most important issues for reducing flood risks as well as floodplain management. Due to the complexity of the flow structure during floods, the use of one-dimensional models will be associated with many approximations and errors in the results. Nowadays, with the progress and development of simulation software and increasing the speed of computer processors, the use of numerical methods has been developed. In recent decades, the characteristics of the flow field in prismatic and non-prismatic composite channels with different geometries have been investigated numerically and experimentally. But so far, limited studies have been done on non-prismatic compound channels with skewed floodplains. There are many uncertainties about the flow characteristics in this type of compound channel. In this research, the Anasys Fluent software and the k-ɛ turbulence model have been used to model the flow field in skewed compound channels with inclined floodplains for two skew angles of ۳.۸۱o and ۱۱.۳۱o. The results of numerical modeling were then compared with experimental data. The results show that the k-ɛ turbulence model is able to predict the velocity and boundary shear stress distributions in compound channels with skewed and inclined floodplains. Also, the k-ɛ turbulence model is able to predict the secondary flows and eddies created in the main channel due to the mass transfer between the flume sub-sections. The research shows that with increasing the skew angle from ۳.۸۱o to ۱۱.۳۱o, the flow velocity increases along the skewed flume portion. The highest velocity difference between the main channel and the floodplains is observed in the initial section of the transition and decreases by moving along the skew part of the flume. As the skew angle increases, the boundary shear stress increases in the whole flume cross-section, especially at the beginning and in the middle sections of the skewed transition. Also, the maximum shear stress is located at the beginning of the skewed transition in the main channel and near the diverging floodplain. Meanwhile, an increase in the relative depth increases the shear stress in the whole cross-section. Also, by increasing the skew angle, the effect of the relative depth on the increase of the shear stress decreases

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