انجمن هیدرولیک ایران نشریه علمی هیدرولیک 2345-4237 6 3 2011 11 22 Assessment of Velocity Profile Variation of Hydraulic Jump in Relation to Changes in the length of Roughness بررسی تغییر پروفیل های سرعت نسبت به تغییر طول زبری در پرش هیدرولیکی 13 24 85485 10.30482/jhyd.2011.85485 FA محمد بزاز بهزاد قربانی حسین صمدی بروجنی Journal Article 2011 03 23 In this study, the variation of velocity profile at different sections of hydraulic jump were evaluated in<br />relation to changes in the length of roughness on a rough bed performing the tests in a flume with<br />length of 12m, width and the height of 0.40m. Nine profile variation tests were carried out for 3<br />Froude numbers and 3 lengths of roughness. In each test, four sections of hydraulic jump were<br />selected in which the velocity was measured at 1 cm intervals. The impact of changes of roughness<br />length on velocity profile was surveyed at short, medium and long reaches of effective length. The<br />results indicated that although the dimensionless velocity profiles on the rough bed are similar, their<br />shapes are different from that of on a smooth bed. The boundary layer was another subject studied in<br />this research. The results showed that the boundary layer thickness increased with an increase in the<br />length of roughness and finally dimensionless boundary layer thickness reaches the values of 0.26 for<br />short and 0.37 for medium and long roughness lengths. https://jhyd.iha.ir/article_85485_f874d58af1fb1ddb0f3283870eaac0fd.pdf