Int. J. Renew. Energy Dev. 2022, 11 (4), 1078-1088 | 1078 https://doi.org/10.14710/ijred.2022.45985 ISSN: 2252-4940/© 2022.The Author(s). Published by CBIORE Contents list available at IJRED website International Journal of Renewable Energy Development Journal homepage: https://ijred.undip.ac.id Analysis of Wake Turbulence for a Savonius Turbine for Malaysia’s Slow-Moving Current Flow Anas Abdul Rahman a * , Kumaran Rajendran a , Ayu Abdul-Rahman b , Gisrina Elin Suhri a , Lakshuman Dass a a Mechanical Engineering Program, Faculty of Mechanical Engineering Technology, Universiti Malaysia Perlis, Pauh Putra Main Campus, 02600 Perlis, Malaysia b Department of Mathematics and Statistics, School of Quantitative Sciences, Universiti Utara Malaysia, 06010 UUM, Sintok, Kedah, Malaysia Abstract. 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. Keywords: Shallow depth, marine energy, velocity recovery, cross flow turbines, vertical-axis turbine @ The author(s). Published by CBIORE. This is an open access article under the CC BY-SA license (http://creativecommons.org/licenses/by-sa/4.0/). Received: 27 th April 2022; Revised: 5 th July 2022; Accepted: 18 th July 2022; Available online:1 st August 2022 1. Introduction Every year, due to increasing populations and economic growth, energy production and consumption drastically increase (Daniel & Nicklas, 2013). The global consumption of electricity is projected to increase by 2.5% per year between 2008 and 2035, from 16,819 to 32,922 TWh (Satrio et al., 2016). Malaysia generates more than 80% of its energy from non-renewable sources, such as fossil fuels and coal (Yaakob et al., 2013), which indicates its significant reliance on fossil fuels. As reported in the Malaysia Energy Statistics Handbook 2020, energy consumption in Malaysia has increased drastically, from 25,558 ktoe in 1998 to 64,658 ktoe in 2018 (Energy Commission of Malaysia, 2020). Interestingly, over this period, energy consumption from petroleum products has decreased by almost 20%, partly due to the large increase in natural gas usage. Renewable energy resources, such as solar, wind, biomass, and ocean energy, must be used to address this issue. Due to its geographical location, Malaysia is blessed with this type of energy, rendering the use of ocean energy a greater concern. European countries are currently at the forefront of the research and development of marine * Corresponding author: Email: anasrahman@unimap.edu.my (A.A. Rahman) energy, which has attracted considerable interest from industries, governments, and academia alike (Magagna & Uihlein, 2015). There are various options for extracting energy from the ocean, classified as wave energy (Musa et al., 2020), tidal barrage (Neill et al., 2021), salinity gradient power (Jung et al., 2022), ocean thermal energy conversion (OTEC) (VanZwieten et al., 2017), and tidal turbine (Marsh et al., 2021). Tidal turbines are considered a cost- effective alternative to harness ocean resources compared to wave energy, OTEC, and salinity gradient power (Chong & Lam, 2013). The tidal turbine generates electricity due to ocean–tide variations (Rahman et al 2019). Tidal forces generated by the sun and moon create tidal motions according to the earth’s rotation (Faez Hassan et al., 2012). Common tidal turbine technologies can be classified as vertical-axis tidal turbines (VATTs), horizontal-axis tidal turbines (HATTs), and oscillating hydrofoils. Examples of VATT devices (commercially available and in prototype stages) are the Kobold, Darrius, Savonius, and Gorlov turbines, while SeaGen and OpenHydro are the examples of HATT. Likewise, stingray is an example of an oscillating hydrofoil device. Research Article