Studi Numerik Penagaruh Variasi Inlet Angle dan Outlet Angle Underbody Channel Terhadap Performa Aerodinamika Undertray Mobil Formula SAE Anargya Mark 3.0

Haidarrazan, Rizal (2024) Studi Numerik Penagaruh Variasi Inlet Angle dan Outlet Angle Underbody Channel Terhadap Performa Aerodinamika Undertray Mobil Formula SAE Anargya Mark 3.0. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Transisi industri otomotif di Indonesia ke arah kendaraan listrik mendorong para engineer di Indonesia untuk melakukan penelitian tentang kendaraan listrik. Salah satu wadah penelitiannya bagi mahasiswa sarjana adalah kompetisi Formula SAE. Anargya ITS adalah tim yang didirikan di Institut Teknologi Sepuluh Nopember dengan tujuan berlaga dalam kompetisi Student Formula SAE Japan (FSAEJ). Untuk mendukung hal tersebut, mahasiswa tim Anargya ITS melakukan penelitian terkait pengembangan mobil listrik Formula SAE, khususnya pada aspek aerodinamika. Perangkat aerodinamika yang digunakan pada mobil terbaru Anargya, yaitu Mark 3.0, adalah undertray. Karakteristik geometri undertray berperan penting dalam menghasilkan downforce dan menurunkan drag. Dua parameter yang diteliti pada penelitian ini adalah inlet angle dan outlet angle pada underbody channel.
Metode penelitian yang digunakan adalah metode numerik computational fluid dynamics 3 dimensi dengan aliran steady dan incompressible menggunakan software ANSYS FLUENT. Simulasi dilakukan pada satu konfigurasi ground clearance mobil. Variasi kecepatan yang digunakan adalah 10,96 m/s dan 20 m/s, dan variasi Re adalah 2,27 x 106 dan 4,14 x 106. Inlet angle divariasikan menjadi 3 variasi, yaitu 3˚, 5˚, dan 7˚, sedangkan outlet angle divariasikan menjadi 3 variasi, yaitu 15˚, 20˚, dan 25˚. Model turbulen yang digunakan adalah K-ω SST. Boundary condition yang digunakan ialah velocity inlet, pressure outlet, wall, dan symmetry. Mesh yang digunakan adalah polyhexcore pada model uji half-car.
Undertray pada mobil Formula SAE Anargya Mark 3.0 membuktikan kemampuannya dalam meningkatkan performa aerodinamika dengan memberikan downforce dan mereduksi drag. Kontribusinya terlihat dalam peningkatan downforce hingga maksimal 57,3% pada kecepatan 10,96 m/s dan 52,4% pada 20 m/s, dengan nilai -ΔCL masing-masing 0,207 dan 0,215. Reduksi drag disebabkan oleh penuntunan aliran yang dari buritan lantai mobil, mengurangi ukuran wake di belakangnya, dengan variasi geometri yang efektif menurunkan drag hingga mencapai 16,7% penurunan drag pada kecepatan 20 m/s (ΔCD = -0,09). Berdasarkan hasil penelitian, meskipun efektif, desain undertray masih memiliki kekurangan seperti kurangnya elemen nozzle dan diffuser untuk optimasi distribusi tekanan negatif di lantai mobil. Untuk dimensi underbody channel, direkomendasikan inlet angle tinggi seperti 7˚ dan panjang inlet yang relatif pendek. Untuk outlet angle, direkomendasikan melakukan variasi dari 15˚ hingga 20˚ untuk menemukan reduksi drag terbesar.
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The transition of the automotive industry in Indonesia towards electric vehicles (EVs) encourages engineers in Indonesia to conduct research on EVs, also involving undergraduate students in the research. One of the research platforms is the Formula SAE competition. Anargya ITS is a team established in Institut Teknologi Sepuluh Nopember to compete in the Student Formula SAE Japan (FSAEJ) competition. To support this, Anargya ITS team students conducted research related to the development of Formula SAE electric vehicle aerodynamics aspects. The aerodynamic device used in Anargya's latest car, the Mark 3.0, is the undertray. The geometry characteristics of the undertray play an important role in generating downforce and reducing drag. The two parameters studied in this research are the inlet angle and outlet angle of the underbody channel.
The research method used is a 3-dimensional computational fluid dynamics numerical method with steady and incompressible flow using ANSYS FLUENT software. Simulations were conducted on a single ground clearance configuration. The velocity variations used are 10,96 m/s and 20 m/s, and the Re variations are 2,27 x 106 and 4,14 x 106. The inlet angle is varied into 3 variations, namely 3˚, 5˚, and 7˚, while the outlet angle is varied into 3 variations, namely 15˚, 20˚, and 25˚. The turbulent model used is K-ω SST. Boundary conditions used are velocity inlet, pressure outlet, wall, and symmetry. The mesh used is polyhexcore on the half-car test model.
Anargya Mark 3.0's undertray manages to improve both the downforce and drag performances of the vehicle. The maximum downforce increase due to the undertray at velocity 10,96 m/s is 57,3% and at 20 m/s is 52,4%, with a -ΔCL value of 0,207 and 0,215 respectively. The apparent reduction in drag coefficient is caused by the diffuser's ability to gradually guide the flow towards atmospheric pressure at the rear-side of the car, thus reducing the size of the low-pressure wake region. The highest drag reduction achieved is 16,7% at velocity of 20 m/s with a ΔCD value of -0,09. Based on the results, this undertray design leaves a lot to be desired considering the downforce increase doesn't yield a negative lift coefficient in all the variations. One solution this paper proposes is adding a nozzle-like feature at the undertray plate to further extract downforce through ground effect. The underbody channel dimensions that are recommended are a large inlet angle such as 7˚ with a relatively short inlet length. The outlet angle should be varied from 15˚ to 20˚ and set on the best reduction in drag.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	cfd, formula student, ground effect, undertray
Subjects:	T Technology > T Technology (General) > T57.62 Simulation T Technology > TL Motor vehicles. Aeronautics. Astronautics > TL521 Aerodynamics, Hypersonic.
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User:	Rizal Haidarrazan
Date Deposited:	12 Aug 2024 06:10
Last Modified:	12 Aug 2024 06:10
URI:	http://repository.its.ac.id/id/eprint/113857

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