Author(s): Mehmet Ardiclioğlu; Serter Atabay; Mazen Omran
Linked Author(s):
Keywords: Natural channel; Discharge; Shear stress; Entropy
Abstract: Determination of flow properties like discharge, velocity and shear stress distributions, especially during flood periods, are among the most important information necessary for flood control, water resources planning and management. Owing to the high flood velocities, flood discharge usually cannot be measured efficiently by conventional methods. Natural river velocity measurements were taken using Acoustic Doppler Velocimeter (ADV) throughout the entire cross-section at two different periods on Sarimsakli River, in Turkey. The entropy parameter found as M=1. 6 for Barsama section from the relationship between the mean and maximum velocities. Discharge calculations by classical velocity-area methods were compared with Entropy based calculation. All methods show very good agreement with integrated discharge calculation. Applicability of logarithmic and entropy-based Chiu’s velocity distribution equations is investigated for natural channel flow. Nikuradse’ equivalent sand roughnesses (ks) for every station were determined using measured velocity distributions. Depend on measured velocities shear velocity (u*) and shear stress (τMeas) were calculated. Chiu’s two-dimensional velocity distributions gave good results with measured profiles look like logarithmic distributions. Darcy’s friction factors (f) and (U u) relation are investigated for Barsama cross-section and second degree polynomial relation is observed, where Ud; mean vertical velocities and umaxi maximum vertical velocity. So using (U u) value local shear stress (τCalc) could be calculated easily. max i d d max i
Year: 2007