  Wind energy has emerged as a viable alternative to fossil fuels, with
vertical axis wind turbines (VAWTs) gaining popularity due to their efficiency
and adaptability. Combining the Actuator Line Method (ALM) with Large Eddy
Simulation (LES) enables accurate performance evaluations, facilitating the
design and optimization of wind turbines. The present study invokes ALM-based
methodology to perform calculations for the VAWTs. The results of the LES
simulations of the VAWTs have been extensively validated against the available
experimental and numerical data. The study further explores a VAWT cluster of
three turbines by investigating the influence of turbine spacing (in both
in-line and staggered configuration) on cluster performance. The study shows
that the configuration with a streamwise separation (Xsep) of 0.34D and a
transverse separation (Ysep) of 2.5D exhibits superior performance to other
combinations owing to increased kinetic energy in the wake for the downstream
turbines. Further, we have presented the effect of varying the rotation
direction (in combinations of Clockwise and Counter-Clockwise rotation) for the
individual turbines in the 3-turbine cluster for the two configurations:
in-line (Xsep = 0D, Ysep = 2.5D) and staggered (Xsep = 0.34D, Ysep = 2.5D).
Staggered counter-rotating turbine cases show reduced performance compared to
co-rotating cases, specifically, the clockwise co-rotating (C-C-C)
configuration. In the in-line configuration, counter-rotating setups outperform
co-rotating ones. Counter-rotation analysis reveals that reducing streamwise
separation allows turbines to align in line without sacrificing performance,
thereby increasing the power density of the turbine cluster
