Simulasi Numerik Karakteristik Aliran 3 Dimensi Di Sekitar Bodi "Sapuangin Speed" Dengan Rasio Ground Clearence Terhadap Panjang Model (C/L) 0.014

Yuliyu, Diaul Vikri (2014) Simulasi Numerik Karakteristik Aliran 3 Dimensi Di Sekitar Bodi "Sapuangin Speed" Dengan Rasio Ground Clearence Terhadap Panjang Model (C/L) 0.014. Other thesis, Insititut Teknologi Sepuluh Nopember.

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Abstract

Formula SAE merupakan kompetisi membuat kendaraan mirip mobil formula yang diikuti oleh seluruh mahasiswa di seluruh dunia termasuk Institut Teknologi Sepuluh Nopember dengan mobil Sapuangi Speednya. Terdapat beberapa kategori perlombaan dalam kompetisi ini diantaranya fuel efficiency. Untuk bisa menghasilkan kendaraan yang memiliki efisiensi bahan bakar maksimal perlu dilakukan analisa aerodinamika pada bodi kendaraan. Bodi Sapuangin Speed memiliki Leading edge yang tumpul sehingga dimungkin adanya multi-stagnation point. Dengan adanya ground clearance berpotensi terbentuk blockage effect pada daerah upstream dekat ground. Aliran cenderung terdefleksi dengan sangat cepat menuju upperside yang seakan-akan menerima sudut serang positif sehingga menggeser posisi titik minimum pressure lebih kedepan. Pada akhirnya, separasi di rear end pun lebih cepat terjadi. Dikarenakan kompleksnya aliran 3D, keterbatasan alat ukur dan tuntutan observasi dan visualisasi yang detail dari karakteristik aliran, maka penelitian ini dilakukan dengan metode numerik (CFD) dengan software Fluent 14. Pemilihan kondisi simulasi digunakan domain di upstream 2L, downstream 4L, lebar 2L, tinggi 2L; model turbulensi k-ε realizable; dan skema interpolasi second-order upwind. Rasio ground clearance terhadap panjang model (C/L) 0.014, ReL = 3.3541 x 10 6 , boundary condition untuk outlet adalah pressure outlet dan untuk inlet adalah velocity inlet sebesar 22.22 m/s; densitas (ρ)=1.225 kg/m3 viskositas (μ)=1.7894 x 10 -5 kg/m.s. Dari penelitian ini dapat diketahui karakteristik aliran 3D disekitar bodi sapuangin speed dengan pengaruh rasio ground clerance terhadap panjang model (C/L) 0.014. Dari hasil simulasi didapatkan bahwa aliran akan cenderung terdefleksi kearah lower sidebody surface yang memiliki hambatan aerodinamika kecil. Aliran ini kemudian mengalir menuju lower bodi lalu berinteraksi dengan aliran pada daerah sidebody sidepot sehingga menghasilkan vortex. Intensitas vortex yang terjadi lebih besar daripada vortex pada daerah rear end m obil. koefisien drag pada simulasi tanpa menggunakan porous lebih besar 1.073% daripada simulasi dengan menggunakan porous. Mobil mengalami gaya angkat yang ditunjukkan oleh nilai koefisien lift yang bernilai positif. Didapatkan juga besar gaya traksi minimal yang dibutuhkan mobil untuk bisa berjalan sebesar 1878,9 N sehingga daya minimal yang harus dimiliki mesin sebesar 41749,158 watt.
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Formula Student is a competition to design and make a car like formula that is followed by all students around the world including Sepuluh Nopember Institute Of Technology that make Sapuangin Speed. There are several categories of race in this competition including fuel efficiency. To be able to produce vehicles that has a maximum fuel efficiency, it is important to analyze the aerodynamics of the vehicle. Sapuangin Speed body has a blunt leading edge. It may cause a multi-stagnation point. Blockage effect can occur in the upstream area near ground because presence of ground clearance. Ground blockage causes flow being deflected to the upper side and create a positive angle of attack, so this condition can move pressure minimum point forward. Because of that separation in rear end occur faster. Due the complexity of the 3D flow, the limitations of measuring instruments and demands on detailed observation and visualization, the analysis may carried out by numerical methods (CFD) through software Fluent 14. Len the of domain is 2L for body upstream , 4L for downstream , 2L for width , 2L for height. Simulation used turbulence model k - ε realizable, and convection term was set to second-order upwind. Ground configuration is enforced with C/L = 0,014, Re L = 1,918 x 106, boundary condition for outlet is the pressure outlet and for inlet is the velocity inlet at 22,22 m / s ; density ( ρ ) = 1.225 kg/m3 ; viscosity ( μ ) = 1.7894 x 10-5 kg / m.s. From this research, we can know the 3D flow characteristics around the sapuangin speed body, with the influence of the ratio of the length of ground clearance model (C/L) 0.014. From the simulation results, showed that the flow has tendency to be deflected towards the lower sidebody surface that has smaller aerodynamic drag. Then, the stream flows to the lower body and interacts with flow from sidebody sidepot resulting vortex. The intensity of the vortex is greater than the vortex at the rear end. Drag coefficient of the simulation without using porous is 1,073 % greater tha n using porous. The car experience lift force indicated by the value of coefficient lift which is positive. Also gained minimum traction at 1878.9 N and engine must have power at least 41749,158 watt.

Item Type: Thesis (Other)
Additional Information: RSM 620.106 4 Yul s-1, 2014
Uncontrolled Keywords: Formula SAE, Sapuangin, efisiensi bahan bakar
Subjects: Q Science > QA Mathematics > QA911 Fluid dynamics. Hydrodynamics
Divisions: Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User: Mr. Marsudiyana -
Date Deposited: 16 Jan 2024 07:25
Last Modified: 16 Jan 2024 07:25
URI: http://repository.its.ac.id/id/eprint/105515

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