@article{Monsif Shinneeb_Ghassan Nasif_Ram Balachandar_2022, title={Secondary Currents at Very Low and High Aspect Ratios of Open Channels}, volume={14}, url={https://semarakilmu.com.my/journals/index.php/CFD_Letters/article/view/573}, DOI={10.37934/cfdl.14.5.115}, abstractNote={<p>The present numerical study is an attempt to better understand the effect of the aspect ratio (AR) on the velocity field characteristics of the fully-developed turbulent flow in a straight open channel by contrasting a very low and very high aspect ratio cases (AR = 1 and 12). The AR is defined as the ratio of the width of the channel in a plane normal to the flow direction, to the flow depth. The bulk velocity and water depth considered in this study are 0.75 m/s and 30 mm, respectively, which yield a Reynolds number of ReH = 22,500. The transient three-dimensional Navier-Stokes equations were numerically solved using a finite-volume approach with improved-delayed detached-eddy simulation (IDDES) turbulence model. The results revealed that the normalized components of the normal stresses by the turbulent kinetic energy k are constant over most of the velocity field, although k varies in magnitude throughout the velocity field in both AR cases. In addition, the results also revealed a strong anisotropic flow which justifies the formation of secondary currents as a means for transporting the kinetic energy. The results also reveal that both vertical and transverse components of the normal stresses are correlated to the side-recirculation zone (SRZ) and bottom-recirculation zone (BRZ), respectively, which highlights the role of the mean recirculation zones (BRZ & SRZ) in the re-distribution of the turbulent kinetic energy k in the velocity field.</p>}, number={5}, journal={CFD Letters}, author={Monsif Shinneeb and Ghassan Nasif and Ram Balachandar}, year={2022}, month={May}, pages={1–15} }