Local and Global Friction Factor in a Channel with V-Shaped Bottom
نویسنده
چکیده مقاله:
This paper presents an experimental research on the distribution of local friction factor, fb, and global friction factor, f, over the cross-section of a channel with V-shaped bottom, which typically occurs in sewers and culverts. Several series of experiments were conducted for measuring velocity and boundary shear stress. It is found that, Darcy-Weisbach, f, is more sensitive than other resistance coefficients such as Manning, n. Local boundary shear stress around wet perimeter, τb, and depth-averaged velocity, Ud, data are used to evaluate fb. The results illustrate that, the friction factor is shown to be a function of flow depth as well as being dependent upon the Froude number, Fr. Therefore, the local friction factor does not remain constant across the channel. Meanwhile, the common technique of assuming a constant friction factor over the entire section of the channel has been found to have theoretical justification. The results indicate that the global friction factor decreases as flow discharge increases and channel bed getting steeper in the experiments including subcritical and supercritical flow conditions. However, it can be seen that the effects of walls are very high at low Froude numbers. In general, the results indicate that the perturbations in the distribution of local friction factor are quite considerable in steeper channels as Froude number increases.
منابع مشابه
Resistance to Flow in a V-Shaped Bottom Channel
Water flow in open channels is always subject to the resistance to flow and energy dissipation. For design purposes, one of the needed variables is the hydraulic resistance coefficient. For this mean, the influence of cross-sectional shape together with secondary flow cells and lateral distribution of true boundary shear stress have not yet been fully explored. This paper surveys the number of ...
متن کاملFACTOR V AND VIII INHIBITOR IN PATIENTS WITH COMBINED FACTOR V AND VIII DEFICIENCY
Patients with coagulation factor(s) deficiency who use coagulation therapy are susceptible to forming inhibitors against coagulation factor(s). In this survey we detected factor V and VIII inhibitor in ten patients with combined deficiency of factors V and VIII from north east of Iran (Khorassan province). It was revealed in our survey that eight patients had both factor V and factor VIII i...
متن کاملA Comprehensive Model for Stiffness Coefficients in V-Shaped Cantilevers
During past decade the AFM based nanomanipulation has been focus of attention as the promising nano fabrication approach. The main challenge in this process is the real-time monitoring. Consequently, the dynamic models have been proposed as a solution to the existing challenge. In the modeling approach the magnitudes of the forces are proportional to the stiffness coefficients o...
متن کاملFasting and diabetes from a local and global perspective- commentary
Fasting is a common practice among people with diabetes (PWD). As healthcare providers we are in a position to assist those who choose to fast to manage their diabetes effectively. Diabetes self-management education for PWD is needed both prior and during the time of fasting to best metabolic control.
متن کاملمنابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ذخیره در منابع من قبلا به منابع من ذحیره شده{@ msg_add @}
عنوان ژورنال
دوره 21 شماره 4
صفحات 325- 336
تاریخ انتشار 2008-12-01
با دنبال کردن یک ژورنال هنگامی که شماره جدید این ژورنال منتشر می شود به شما از طریق ایمیل اطلاع داده می شود.
میزبانی شده توسط پلتفرم ابری doprax.com
copyright © 2015-2023