This study presents a detailed computational fluid dynamics (CFD) investigation into the aerodynamic performance of the NREL Phase VI wind turbine, focusing on torque and power generation under different turbulence models. The primary objective was to analyse the effect of various turbulence models and their responses in wind turbine torque generation. Furthermore, it also investigates the distance effect on wind velocity deficit. The research utilizes 2D and 3D simulations of the S809 airfoil and the full rotor, examining the predictive capabilities of the k-epsilon, k-omega, and k-omega SST turbulence models. The study incorporates both experimental validation and wake analysis using the Gaussian wake model to assess wind velocity deficits. Simulations were conducted for a wind speed range of (6–10 m/s), with results indicating that the k-epsilon model provided the closest match to experimental data, particularly at higher wind speeds within the targeted range. Even though k-epsilon results had better agreement when validated with experimental data, theoretically k-omega (SST) should perform better as it combines k-epsilon and k-omega advantages in predicting the flow regardless of its farness from the wall. However, in simulations using the k-omega (SST), the separation of flow and the shear stress transients were only visible at wind speeds of 10 m/s or higher. Wake effects, on the other hand, were found to cause significant velocity deficits behind the turbine, following an exponential decay pattern. The findings offer valuable insights into improving wind turbine performance through turbulence model selection and wake impact analysis, providing practical guidelines for future wind energy optimizations.

The climate change has become one of the most serious problems that threat our planet recently due to greenhouse gas emissions from fossil fuel-based power generating. However, its dangerous effects cannot be avoided or reduced until attentions are paid, and efforts are made to change the existing energy systems. In contrast, renewable energy provides the best potential for both relieving climate change and substituting fossil fuel. Solar energy is a promising and freely available energy source among other renewable sources of energy. This study aims to assess the potentiality of solar energy by identifying seasonal variations of solar energy in Malaysia, Alor Setar city. The meteorological readings data of two years including latitude, longitude, altitude, temperature, relative humidity, precipitation rate, and global solar radiation are used. The parameters needed for the assessment are declination angle, sunset hour angle, extra-terrestrial radiation, monthly mean daily global radiation on horizontal surface, coefficient of Angstrom (a,b), and clearness index. It was found that the average global solar radiation at the location, maximum sunshine duration, and extraterrestrial radiation to be 18.89 MJm2, 12.00 hours, and 35.82 Mi/m2/j, respectively. Objectively, there is a huge solar energy potential in Alor Setar. At the bottom line, the study and the data of two years have brought a better view of the solar energy potentials in state.