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Analysis of the Effect of Bottom Blade Inclination Angle Variations on Torque in Vortex Turbines Using Computational Fluid Dynamics (CFD) Badri Kurniawan; Randi Purnama Putra; Yolli Fernanda; Fitrah Qalbina
Jurnal Vokasi Mekanika (VoMek) Vol 7 No 3 (2025): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/vomek.v7i3.887

Abstract

The development of renewable energy in Indonesia is a strategic effort to meet increasing energy demands while reducing dependence on fossil fuels. One promising approach is utilizing river flow for micro-hydro power generation, particularly with vortex turbines that operate efficiently under low head and discharge conditions. This study aims to analyze the effect of varying bottom blade inclination angles on the torque generated by a vortex turbine using Computational Fluid Dynamics (CFD) simulations. The research employed ANSYS Fluent with a k-? SST turbulence model and used a three-dimensional numerical method to evaluate three inclination angles: 22.5°, 32°, and 42°. The results show that blade inclination significantly influences torque values, with the 22.5° angle producing the highest torque of 10.95 Nm, followed by 32° at 10.79 Nm, and 42° at 10.58 Nm. These findings indicate that optimizing blade inclination improves turbine performance, contributing to the development of efficient micro-hydro systems for renewable energy applications.
Utilizing Augmented Reality Media to Enhance Students’ Lathe Learning Outcomes Ariansyah Ariansyah; Febri Prasetya; Purwantono Purwantono; Randi Purnama Putra
Jurnal Vokasi Mekanika (VoMek) Vol 7 No 3 (2025): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/vomek.v7i3.889

Abstract

The integration of technology in vocational education has become a critical need to support 21st-century skills, especially in practice-based learning such as Basic Mechanical Engineering subjects. One promising innovation is the use of Augmented Reality (AR) media, which enables interactive three-dimensional visualization to help students concretely understand abstract concepts. This study aims to examine the effectiveness of lathe-based AR media in improving student learning outcomes and motivation in Grade X of the Machining Engineering Department at SMK Semen Padang. The research employed a quasi-experimental method using a non-equivalent control group design. The subjects consisted of two classes: the experimental class (using AR media) and the control class (using conventional learning methods). Data were collected using pre-tests and post-tests to assess learning outcomes and Likert-scale questionnaires to evaluate learning motivation. The analysis results showed that the use of AR media significantly increased student learning outcomes and motivation compared to traditional methods. Based on hypothesis testing and normalized gain score analysis, the AR media was found to be highly effective in the learning process. In conclusion, lathe-based Augmented Reality media proved to be an effective interactive learning tool that enhances students' academic performance and motivation, while also contributing to the development of innovative media in technical education.
Analysis Of The Effect Of Penstock Diameter Variation And Nozzle Flow Velocity On Pelton Turbine Performance Using Computational Fluid Dynamics (CFD) Revaldo Nur Hidayat; Randi Purnama Putra; Yolli Fernanda; Fitrah Qalbina
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 2 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/18k9e415

Abstract

The performance of a Pelton turbine in micro-hydropower plants is influenced by penstock design and fluid flow conditions. Variations in penstock diameter can lead to changes in head loss, flow velocity, and energy transfer efficiency. This study aims to analyze the effect of penstock diameter variation and nozzle flow velocity on Pelton turbine performance under different head conditions using the Computational Fluid Dynamics (CFD) method.Simulations were conducted using penstock diameters of 4 inches, 5 inches, and 6 inches with ANSYS software. The results show that the respective head losses are 0.010 m, 0.006 m, and 0.0028 m, indicating that larger diameters reduce friction losses in the flow. The corresponding nozzle velocities are 8.90 m/s, 9.08 m/s, and 8.64 m/s, with the highest value observed at the 5-inch diameter due to the balance between flow rate and energy losses. The resulting torque values are 2.13 Nm, 2.55 Nm, and 2.60 Nm, while the rotor rotational speeds are 150.87 W, 189.07 W, and 194.90 W. The effective power generated is 65.59 W, 80.21 W, and 77.79 W, with efficiencies of 43.77%, 42.44%, and 39.95%, respectively. The results indicate that a 5-inch penstock diameter provides the most optimal performance, as it achieves the best balance between head loss, flow distribution, and fluid energy transfer.
Design and Crash Test on a Two-Passenger City Car Frame using Finite Element Method Randi Purnama Putra; Dori Yuvenda; Wanda Afnison; Remon Lapisa; Milana Milana; Anna Niska Fauza; Dani Harmanto
Automotive Experiences Vol. 7 No. 2 (2024)
Publisher : Universitas Muhammadiyah Magelang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31603/ae.11306

Abstract

The chassis is an important part of a car which must have a strong construction to withstand the weight of the vehicle. The purpose of this research is to create a city car's chassis that can hold two passengers and then crash-test the finished product. In this research, a development method was used using SolidWorks software and the student version of ANSYS R2 2023 as software for creating chassis designs and crash test simulations. The study's findings indicate that the car frame's measurements are 2.46 meters in length, 1.33 meters in height, and 1.39 meters in width. The steel of the ASTM A36 type was utilized as the material in the computational study of the frame. The results show that increasing speed causes an increase in deformation, with the peak deformation at a speed of 100 km/h. The maximum deformation occurs at 0.007 seconds with a value of 203.51 mm at the top pillar of the car. The deformation increases from 97.196 mm at 0.0035 s to 161.22 mm at 0.0056 s. However, deformation occurs mainly in the front zone of the car frame and is not significant in the passenger zone.
Aerodynamic Approach to Two-Passenger City Car Design: A Study of Square Back and Compact Shapes Randi Purnama Putra; Dori Yuvenda; Remon Lapisa; Wanda Afnison; Milana Milana; M. Yasep Setiawan; Ahmad Arif; Dani Harmanto
Automotive Experiences Vol. 8 No. 2 (2025)
Publisher : Universitas Muhammadiyah Magelang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31603/ae.13686

Abstract

The development of lightweight electric cars for urban mobility requires efficient aerodynamic design without sacrificing space efficiency. This study presents a novel method by investigating the combination of a two-seater city car's compact dimensions and square back shape, which has not been extensively researched for low- to medium-velocity vehicles. This study's objective is to assess the design's aerodynamic performance using numerical simulations using the Computational Fluid Dynamics (CFD) approach. The vehicle model is designed with a compact body and square back, which is commonly used in small vehicles with high maneuverability requirements. The simulations are conducted at three different air velocity levels: 10, 20, and 30 m/s. The results of the study showed an increase in the value of the drag coefficient (Cd) along with an increase in flow velocity. At a velocity of 10 m/s, the Cd value was recorded at 0.4536. When the velocity increased to 20 m/s, the drag coefficient increased slightly to 0.4563. Further increases in velocity to 30 m/s resulted in a Cd value of 0.4581. This Cd value shows the consistency of aerodynamic performance with increasing velocity, with fluctuations that remain within the efficiency limits of lightweight vehicles. The pressure distribution contour shows high-pressure accumulation at the front and low pressure at the rear of the vehicle, which generates large turbulent wakes in the rear area and contributes to increased drag. These findings indicate that the square rear body design faces significant aerodynamic challenges. Therefore, design strategies such as adding a rear spoiler, using a rear diffuser, and optimizing the rear body angle are suggested as potential solutions to improve flow efficiency.