Study on the Effect of Guide Wall on the Transverse Velocity in the Bend
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RESEARCH ARTICLE-CIVIL ENGINEERING
Study on the Effect of Guide Wall on the Transverse Velocity in the Bend Jing Zhang1,2 · Tiantian Wang3 · Qinghua Zhang2 Received: 11 April 2020 / Accepted: 31 October 2020 © King Fahd University of Petroleum & Minerals 2020
Abstract It is very important to understand the vertical transverse velocity distribution of the bend with the guide wall set on the axis to explain the improvement mechanism of the flow characteristics in the bend. Therefore, the effect of the guide wall on the transverse velocity under different parameters of the bend was presented. Considering the feature design of channel bend in real engineering project, axis, bottom slopes and discharges with two flow conditions were used as parameters. Analysis and observation showed the significant impact on the transverse velocity, the guide wall impact on both absolute value and the direction of the transverse velocity distribution and present certain laws. The absolute value is influenced by the change of velocity direction, while the direction is affected by the inlet flow condition. In contrast, the transverse velocity is effectively reduced by the installation of a guide wall, and the water depth differences are reduced as well. Therefore, the impact of the guide wall on the flow characteristic especially the transverse velocity was proved and these results are practically useful in channel bend design. Keywords Bend · Guide wall · Transverse velocity · Distribution · Parameters of the bend
List of Symbols
1 Introduction
B i R v Q F
Water will be bended when it flows through a river bend or a channel bend. Under the combined action of centrifugal inertial force, gravity and the curved boundary, water surface and velocity gradually change along the axis toward downstream, and the flow characteristics become extremely complex while developing some unique patterns of the supercritical flow in the bend like the transverse gradient of water surface, transverse velocity, secondary currents and the diamond wave. Since Thomson [1] discovered that there exists both vertical and horizontal flow in the bended channel by experiment, and many scholars conducted a lot of researches on the bended flow and gradually formed a systematical theories. The American scholar Ippen [2] systematically discussed the problem of shock waves in the supercritical flow in the bended channel. Engelund [3] studied the law of the flow in the bend and established a formula for the longitudinal velocity distribution. Hersberger [4] used an ultrasonic Doppler velocity meter to analyze the three-dimensional flow field distribution. Bodnár and Príhoda [5] carried out the research of free water surface in the bend through numerical simulation.
B
The net width of the channel The bottom slope The axial radius of the bend The average velocity at entrance of the bend The discharge Froude number
Qinghua Zhang [email protected] Jing Zhang [email protected]
1
State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Ti
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