Laboratory Investigation on the Effect of Permeable Spur Dike Length on Scour Hole Dimensions in a Mild 90 Degrees Bend under Non-Submerged Conditions
Abstract:
One of the common ways for bank protection against erosion along rivers’ bends is spur dike application. Spur dike changes the flow pattern and diverts it towards the river centerline and as aresult protect the river bank from erosion. However, a new flow pattern is formed with higher velocities and this phenomenon causes the local scour around the structure nose to be increased. The length of spur dike is one of the important parameters affecting the local scour around the structure. In order to investigate the effect of the permeable spur length (permeability was 33%) on local scour, experiments were conducted in a rectangular laboratory flume with a mild 90 degree bend (R/B=4; where R=radius and B=flume width). In this research a series of spur dikes with three different spur length including 10.5, 14.0 and 17.5 cm, corresponding to 0.15, 0.2 and 0.25 of flume width, respectively, was installed along the bend for each experiment. Four Froude number values including 0.21, 0.23, 0.26 and 0.28 with a constant flow depth of 14cm under clear water condition were applied for each spur length. The results show that the maximum scour depth increased with increasing the spur length for a constant Froude number; so that the maximum scour depth was happened for the length of 17.5cm with a Froude number of 0.28, which was 10.71% and 42.86% more than the spurs with 14.0m and 10.5cm length, respectively. The maximum local scour was observed to happen at the end part of the outer bank of the bend. It was generally found that with increasing Froude number and the spur length the scour hole dimensions increased.
Language:
Persian
Published:
Journal of Water and Soil Science, Volume:26 Issue: 2, 2016
Pages:
163 to 175
magiran.com/p1603441  
دانلود و مطالعه متن این مقاله با یکی از روشهای زیر امکان پذیر است:
اشتراک شخصی
با عضویت و پرداخت آنلاین حق اشتراک یک‌ساله به مبلغ 990,000ريال می‌توانید 70 عنوان مطلب دانلود کنید!
اشتراک سازمانی
به کتابخانه دانشگاه یا محل کار خود پیشنهاد کنید تا اشتراک سازمانی این پایگاه را برای دسترسی نامحدود همه کاربران به متن مطالب تهیه نمایند!
توجه!
  • حق عضویت دریافتی صرف حمایت از نشریات عضو و نگهداری، تکمیل و توسعه مگیران می‌شود.
  • پرداخت حق اشتراک و دانلود مقالات اجازه بازنشر آن در سایر رسانه‌های چاپی و دیجیتال را به کاربر نمی‌دهد.
دسترسی سراسری کاربران دانشگاه پیام نور!
اعضای هیئت علمی و دانشجویان دانشگاه پیام نور در سراسر کشور، در صورت ثبت نام با ایمیل دانشگاهی، تا پایان فروردین ماه 1403 به مقالات سایت دسترسی خواهند داشت!
In order to view content subscription is required

Personal subscription
Subscribe magiran.com for 50 € euros via PayPal and download 70 articles during a year.
Organization subscription
Please contact us to subscribe your university or library for unlimited access!