TY - JOUR
T1 - Three-dimensional numerical analysis of a vertical axis autorotation current turbine (VAACT)
T2 - effects of lateral blockage and free surface
AU - Wu, Hao
AU - Yang, Shuojia
AU - Wang, Enhao
AU - Cao, Renjing
AU - Fernandes, Antonio Carlos
AU - Yin, Xianghan
AU - Xiao, Qing
PY - 2024/9/1
Y1 - 2024/9/1
N2 - In this study, we conduct an in-depth three-dimensional (3D) numerical analysis of an innovative vertical axis autorotation current turbine (VAACT), focusing on examining the effects of lateral blockage and free surface on its performance. This analysis employs detached eddy simulation (DES) integrated with the sliding mesh and the volume of fluid algorithm. To begin with, the time series data of angular velocities acquired during the power output phase indicates that, within the range of 0.05 to 0.213, an increased blockage ratio positively influences the turbine’s rotational stability and improve its efficiency. Further, the extrapolation from the fitted curve of the mean power coefficient (
C
P
¯
) as a function of lateral blockage ratio suggests that, in the absence of lateral blockage, the
C
P
¯
value would approximate 0.145. Additionally, it is observed that the free surface generally diminishes the turbine’s rotational speed and power. This effect is particularly pronounced when the free surface fluctuation is large relative to the turbine’s submerged height. Notably, two parallel rows of 3D vortices on the free surface periodically detach in the wake, and the vortices downstream of the retreating edge appear stronger. This study also presents and analyses detailed flow field characteristics, including 3D vortical structures, free surface fluctuations, and vorticity contours. Overall, this research enhances the comprehension of this innovative vertical-axis turbine, offering valuable knowledge for its potential practical deployment.
AB - In this study, we conduct an in-depth three-dimensional (3D) numerical analysis of an innovative vertical axis autorotation current turbine (VAACT), focusing on examining the effects of lateral blockage and free surface on its performance. This analysis employs detached eddy simulation (DES) integrated with the sliding mesh and the volume of fluid algorithm. To begin with, the time series data of angular velocities acquired during the power output phase indicates that, within the range of 0.05 to 0.213, an increased blockage ratio positively influences the turbine’s rotational stability and improve its efficiency. Further, the extrapolation from the fitted curve of the mean power coefficient (
C
P
¯
) as a function of lateral blockage ratio suggests that, in the absence of lateral blockage, the
C
P
¯
value would approximate 0.145. Additionally, it is observed that the free surface generally diminishes the turbine’s rotational speed and power. This effect is particularly pronounced when the free surface fluctuation is large relative to the turbine’s submerged height. Notably, two parallel rows of 3D vortices on the free surface periodically detach in the wake, and the vortices downstream of the retreating edge appear stronger. This study also presents and analyses detailed flow field characteristics, including 3D vortical structures, free surface fluctuations, and vorticity contours. Overall, this research enhances the comprehension of this innovative vertical-axis turbine, offering valuable knowledge for its potential practical deployment.
KW - detached eddy simulation
KW - vertical-axis hydrokinetic turbine
KW - slide mesh
KW - lateral blockage effect
KW - free surface effect
UR - https://data.mendeley.com/datasets/7hvcm36r98/1
UR - https://doi.org/10.17868/strath.00090080
U2 - 10.1016/j.apor.2024.104138
DO - 10.1016/j.apor.2024.104138
M3 - Article
SN - 0141-1187
VL - 150
JO - Applied Ocean Research
JF - Applied Ocean Research
M1 - 104138
ER -