Aqua (May 2024)
Reynolds number effect on the parameters of turbulent flows over open channels
Abstract
Experimental investigations were conducted to analyze the effect of Reynolds numbers on turbulent flow properties in a nonuniform sand bed channel. Steady flow simulations were performed over the nonuniform sand bed channel, considering five Reynolds numbers within the range of 36500–53886. This article endeavors to delineate the influence of Reynolds number on turbulent flow properties through meticulous laboratory studies. Observations revealed that higher Reynolds numbers corresponded to increased longitudinal velocity. As the Reynolds number increases by 10 to 47%, various turbulent flow properties exhibit distinct trends. Specifically, the longitudinal velocity, longitudinal turbulent intensity, vertical turbulent intensity, turbulent kinetic energy, Reynolds shear stress, and Taylor scale show increases ranging from 5 to 30%, 15 to 25%, 15 to 20%, 25 to 60%, 20 to 40%, and 35 to 45%, respectively. Taylor scale analysis indicated higher magnitudes associated with higher Reynolds numbers. In-depth examinations of turbulent anisotropy, third-order moments of velocity fluctuations, kurtosis, turbulent kinetic energy production, and dissipation provided additional insights into flow behavior across different Reynolds numbers. This study contributes to a more comprehensive understanding of flow dynamics in nonuniform sand bed channels under varying Reynolds number conditions, bridging the gap between laboratory studies and real-world scenarios. HIGHLIGHTS Reynolds number variations impact turbulent flow characteristics.; Longitudinal velocity and turbulent intensity increase with higher Reynolds numbers.; Reynolds shear stress and turbulent kinetic energy also rise with increasing Reynolds numbers.; Taylor scale reveals larger magnitudes associated with higher Reynolds numbers.; Insights into turbulent anisotropy and kurtosis enhance flow dynamics understanding.;
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