The placement of tidal turbines in a tidal farm is challenging owing to the flow resistance caused by individual devices. To successfully deploy tidal turbines, the wake interaction between devices, often determined by the array's layout and spacing, must be understood. In this study, the impact of array configuration for shallow water application is examined numerically using computational fluid dynamics (CFD). This is to propose a suitable array structure for possible implementation in Malaysia. This numerical study uses 15 turbines in a staggered and squared array with two sets of lateral and longitudinal spacing combinations. The horizontal axis tidal turbine (HATT) and vertical axis tidal turbine (VATT) are represented using disc and cylindrical models, respectively. The VATT with staggered setup and greater spacing model demonstrates faster wake recovery (between 10% to 21%), compared to the squared arrangement. This meets the far wake criteria and reduces the chance of wake mixing. It is also suitable for shallow depth implementation.

With Malaysia being surrounded by water bodies, tidal energy could be used for energy extraction. While several turbine designs and technologies have been used for tidal energy extraction, information on the use of vertical-axis tidal turbines (VATTs) for shallow-water applications is scarce. However, implementing horizontal-axis tidal turbines (HATTs) is not feasible due to Malaysian ocean depths. Hence, examining the wake-flow characteristics of VATTs in a shallow water-working environment in Malaysia is essential. The wake turbulence of the Savonius turbine model was compared with that of a hypothetical ‘actuator' cylinder, a VATT representation. Subsequently, the wake turbulences of a Savonius turbine model in static and dynamic simulations were compared to understand the flow distinction. Compared with that exhibited by the hypothetical actuator cylinder of 2.5 m, the hypothetical actuator cylinder of 5 m exhibits greater velocity deceleration. Additionally, the modelled Savonius turbine exhibits significantly more deceleration than that exhibited by the hypothetical actuator cylinder. Finally, the analysis of the static model of the Savonius turbine shows deceleration that is greater than that of the dynamic model.

Towards  modernisation of the technological era, electricity demands have been an issue. Although the supply of electrical energy from the renewable sources are increasing, it is still not sufficient to offset the carbon production. Malaysia as a developing country needs ample of supply of electrical energy. As most of the current electrical energy for the country are being produced by non renewable sources, the Malaysian government have started looking into renewable options to produce electrical energy. There are various sources of energy that are available in Malaysia such as solar, natural gas, petroleum, ocean energy and many more. This paper is focused on the tidal energy which is an ocean energy that can produce electrical energy by using the power of tide. This research explores the hybrid turbine design which is a type of vertical-axis tidal turbine that combines two distinct type of devices, namely Savonius and H-Darrieus turbines. Hybrid turbine is useful as it helps to overcome the limitation of individual turbine and also be able to produce energy at a low water velocity. Numerical analysis is employed to investigate the wake recovery behaviour and turbulent mixing due to the positioning of the device using Ansys CFD Fluent. By understanding the general wake characteristics produced by each device, proper planning can be done to configure these devices in an array for future planning. The simulation result shows that the hybrid turbine utilising NACA0015 and NACA0018 with nested configuration demonstrates faster velocity recovery compared to NACA0021. The turbulence wake results also provides a promising output which shows the acceleration of flow at the downstream region for hybrid nested NACA0015 and NACA0018 are more narrow compared to NACA0021. The result of this simulation has also been validated with published data. In a nutshell, the NACA blade design not only affects the performance of the turbine but can also influence the velocity recovery downstream of the device.

Over the past years, electrical energy demand has increased dramatically worldwide. Malaysia being a developing country, the need for electrical energy is expected to rise yearly. Therefore, to prevent the energy crisis and global warming, the Malaysian Government has started to switch focus to renewable energy technologies. This paper will analyse the wake characteristics produced by the vertical axis tidal turbine design. Malaysian waters have shallow depth and low water current speed, contributing to an ideal solution to implement a nested turbine. The numerical analysis compares the wake generated from the actual turbine design and a hypothetical ‘actuator’ cylinder which represents vertical axis tidal turbine. The simulation result has been validated with other studies which brings about the understanding of the wake generated from nested turbine and ‘actuator’ cylinder.

The arrangement of tidal turbines in the tidal farm is known to be complicated due to the resistance to the tidal flow which causes the flow to be channeled around the individual devices. To successfully implement the tidal turbine, the wake interaction between the device and its implication needs to be fully understood. Typically, the wake interaction in the array depends on the arrangement and spacing between the device in the array. In this study, a numerical analysis is conducted through the use of Computational Fluid Dynamic (CFD) approach to investigate the influence of the array setup in shallow water application and to propose a suitable array layout for possible application in Malaysia. The numerical analysis is carried out with 2 combination sets of lateral and longitudinal spacing covering 15 turbines in staggered and squared array layout. Hypothetical ‘actuator’ disk and ‘actuator’ cylinder model are used to represent the Horizontal axis turbine (HATT) and Vertical axis turbine (VATT) respectively. The results showed that the VATT model has faster wake recovery and obeys the definition of the far wake. Staggered arrays with bigger spacing are preferable for application in shallow water due to the low probability of wake merging between the rows.