Journal of Mechatronics, Electrical Power, and Vehicular Technology 11 (2020) 95-101 Journal of Mechatronics, Electrical Power, and Vehicular Technology e-ISSN: 2088-6985 p-ISSN: 2087-3379 www.mevjournal.com doi: https://dx.doi.org/10.14203/j.mev.2020.v11.95-101 2088-6985 / 2087-3379 ©2020 Research Centre for Electrical Power and Mechatronics - Indonesian Institute of Sciences (RCEPM LIPI). This is an open access article under the CC BY-NC-SA license (https://creativecommons.org/licenses/by-nc-sa/4.0/). MEV is Sinta 2 Journal (https://sinta.ristekbrin.go.id/journals/detail?id=814) accredited by Ministry of Research & Technology, Republic Indonesia. Numerical investigation of the effect of triangle strut in vertical axis wind turbine (VAWT) Tri Admono a, *, Yoyon Ahmudiarto a , Amma Muliya Romadoni a , Iman Abdurahman a , Agus Salim a , Teguh Tri Lusijarto a , Mochammad Agoes Mulyadi b a Research Centre for Electrical Power and Mechatronics, Indonesian Institute of Sciences (LIPI) Komplek LIPI Jl. Sangkuriang, Building 20, Bandung 40135, Indonesia b Department of Aeronautics and Astronautics, Bandung Institute of Technology Jl. Ganesa No.10, Lb. Siliwangi, Bandung, West Java, 40132, Indonesia Received 23 September 2020; Accepted 11 November 2020; Published online 22 December 2020 Abstract Strut is used in vertical axis wind turbine (VAWT) to restraint the framework. In this study, struts are analyzed to show the pressure losses in VAWT. ANSYS computational fluid dynamics (CFD) software is used to investigate triangle strut in VAWT. This study aims to show a CFD simulation of struts, which affects the aerodynamic of VAWT. In CFD software, the aerodynamic of VAWT can be analyzed in terms of pressure losses in the struts. The simulation method starts by making a struts model, then meshing and setting up ANSYS's boundary conditions. The last iteration runs in ANSYS until convergence. Our results show the percentage of pressure losses with the variation of the angle of wind 0°, 20°, 40°, and 60° are 0.67 %, 0.52 %, 0.48 %, and 0.52 %. The effect of triangle strut in VAWT did not affect the wind flow to the VAWT blade. The results also indicated that the triangle strut could be applied in the multi-stage of VAWT system. ©2020 Research Centre for Electrical Power and Mechatronics - Indonesian Institute of Sciences. This is an open access article under the CC BY-NC-SA license (https://creativecommons.org/licenses/by-nc-sa/4.0/). Keywords: vertical axis wind turbine (VAWT); triangle strut; computational fluid dynamics (CFD); pressure losses. I. Introduction Nowadays, people are interested in using renewable energy because of its zero emissions and also reduce the dependence on fossil fuels [1]. With the growth of the demand for application in renewable energy, the wind turbine is implemented in the urban environment. However, the design of the wind turbine must be considered, especially the design of the strut [2]. Vertical axis wind turbine (VAWT) different from the horizontal axis wind turbine (HAWT) in rotor kinematics, rotor aerodynamics, and wake structure [3]. In the wake structure, a strut keeps the wind turbine stable in the framework. The strut of VAWT is a crucial component. As such, an engineer must consider the strut to have a good performance for VAWT. In the vertical axis turbine, commonly there are two configurations of the turbine, namely open- ended and squirrel-wheel design, as shown in Figure 1 [4]. In the open-ended type usually used in the wind turbine, the blade is connected to the turbine axis using struts. The number of struts to support the blades varies, depending on the geometry of the turbine, length, radius, solidity, and blade size. On the other hand, squirrel-wheel type, or closed-type with the circle in shape usually used in marine turbines. In any case, both open-ended and squirrel- wheel can be applied in the wind or marine turbine. Investigating VAWT strut is substantial because it is related to the aerodynamics of wind turbines. Any interference can affect the pressure losses of VAWT, (a) (b) Figure 1. (a) Open-ended type; (b) Squirrel-wheel type * Corresponding Author. Tel: +62-813-2059-4714 E-mail address: tri.admono@yahoo.com