International Journal of Power Electronics and Drive Systems (IJPEDS) Vol. 13, No. 2, June 2022, pp. 1140~1149 ISSN: 2088-8694, DOI: 10.11591/ijpeds.v13.i2.pp1140-1149  1140 Journal homepage: http://ijpeds.iaescore.com Design and performance of very low head water turbines using a surface vorticity model algorithm Ridwan Arief Subekti 1,2 , Budi Prawara 3 , Anjar Susatyo 2 , Ahmad Fudholi 2,4 , Sastra Kusuma Wijaya 1 , Arief Sudarmaji 1 1 Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, Indonesia 2 Research Centre for Electrical Power and Mechatronics, National Research and Innovation Agency (BRIN), Bandung, Indonesia 3 Research Centre for Electronics and Telecommunication, National Research and Innovation Agency (BRIN), Bandung, Indonesia 4 Solar Energy Research Institute, Universiti Kebangsaan Malaysia, Bangi, Malaysia Article Info ABSTRACT Article history: Received Sep 20, 2021 Revised Feb 10, 2022 Accepted Feb 28, 2022 This study explores the numerical optimization of water turbine runner profile performance using a surface vorticity model algorithm. The turbine is designed on a laboratory scale and operates at a net head of 0.09 m, 400 rpm, and a water flow rate of 0.003 m 3 /s. The initial design of the turbine runner was optimized to minimize losses in the hydrofoil. The optimization algorithm is coded in MATLAB software to obtain the optimal stagger angle that will be used in the water turbine design. Furthermore, design validation was performed using computational fluid dynamics analysis ANSYS CFX to determine the water turbine performance. The settings used in ANSYS CFX include the reference pressure of 1 atm, turbulence model shear stress transport, and inlet boundary conditions using total pressure and static pressure outlet boundary conditions. The computational fluid dynamics analysis reveals that by optimizing the design, the efficiency of the water turbine increases by approximately 2.6%. The surface vorticity model algorithm can be applied to optimize the design of the water turbine runner. Keywords: Hydroelectric power Potential flow analysis Computational fluid dynamics Renewable energy This is an open access article under the CC BY-SA license. Corresponding Author: Sastra Kusuma Wijaya Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia Depok, West Java, Indonesia Email: skwijaya@sci.ui.ac.id 1. INTRODUCTION The development of small and medium scale hydroelectric power plants in Indonesia is currently growing rapidly. This situation arises because the potential is quite large and is in line with the government’s program to develop renewable energy resources. Geographically, Indonesia is an archipelagic country. The unequal distribution of electricity load centers as well as the low level of electricity demand in several regions are factors that hinder the supply of electrical energy on a national scale. Facilities in disadvantaged, frontier, and outermost areas are particularly disadvantaged. The decreasing availability of fossil energy sources and increasing awareness to preserve the environment will encourage the increased use of alternative energy sources. Pico and micro hydro power plants are also widely developed in developing countries [1]–[4]. The water turbine is one of the main components of a hydropower system. Thus, good turbine design is necessary to endow the generator with high efficiency. One method to optimize the design of the water turbine runner is to use surface vorticity model analysis which is a boundary integral method for evaluating fluid flow. The surface vorticity model has been developed and applied as a predictive tool for various engineering problems, such as for handling potential flows for any situation, including lifting bodies. Surface vorticity modelling offers the advantage of being the most natural of all boundary integral techniques [5].