scholarly journals Aerodynamic study of three cars in tandem using computational fluid dynamics

2021 ◽  
Vol 15 (3) ◽  
pp. 8228-8240
Author(s):  
H. Abdul-Rahman ◽  
H. Moria ◽  
Mohammad Rasidi Mohammad Rasani
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Coefficient ◽  
Model Comparison ◽  
Cfd Simulation ◽  
Positive Impact ◽  
Lift Coefficient ◽  
Experimental Studies ◽  
Intelligent Transport System ◽  
Drag Coefficients

Aerodynamics of vehicles account for nearly 80% of fuel losses on the road. Today, the use of the Intelligent Transport System (ITS) allows vehicles to be guided at a distance close to each other and has been shown to help reduce the drag coefficients of the vehicles involved. In this article, the aim is to investigate the effect of distances between a three car platoons, to their drag and lift coefficients, using computational fluid dynamics. To that end, a computational fluid dynamics (CFD) simulation was first performed on a single case and platoon of two Ahmed car models using the STAR-CCM+ software, for validation with previous experimental studies. Significant drop in drag coefficients were observed on platoon models compared to a single model. Comparison between the k-w and k-e turbulence models for a two car platoon found that the k-w model more closely approximate the experimental results with errors of only 8.66% compared to 21.14% by k-e turbulence model. Further studies were undertaken to study the effects of various car gaps (0.5L, 1.0L and 1.5L; L = length of the car) to the aerodynamics of a three-car platoon using CFD simulation. Simulation results show that the lowest drag coefficient that impacts on vehicle fuel savings varies depending on the car's position. For the front car, the lowest drag coefficient (CD) can be seen for car gaps corresponding to X1 = 0.5L and X2 = 0.5L, where CD = 0.1217, while its lift coefficient (CL) was 0.0366 (X1 and X2 denoting first to second and second to third car distance respectively). For the middle car, the lowest drag coefficient occurred when X1 = 1.5L and X2 = 0.5L, which is 0.1397. The lift coefficient for this car was -0.0611. Meanwhile, for the last car, the lowest drag coefficient was observed when X1 = 0.5L and X2 = 1.5L, i.e. CD = 0.263. The lift coefficient for this car was 0.0452. In this study, the lowest drag coefficient yields the lowest lift coefficient. The study also found that for even X1 and X2 spacings, the drag coefficient increased steadily from the front to the last car, while the use of different spacings were found to decrease drag coefficient of the rear car compared to the front car and had a positive impact on platoon driving and fuel-saving.

scholarly journals STUDY OF MESH REFINEMENT ON THE AERODYNAMIC COEFFICIENTS FOR NACA2412 PROFILE WITH DIFFERENT ANGLE OF ATTACK AND k - w TURBULENCE MODEL

2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Nícolas Lima Oliveira ◽  
Eric Vargas Loureiro ◽  
Patrícia Habib Hallak
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Coefficient ◽  
Turbulence Model ◽  
Lift Coefficient ◽  
Mesh Refinement ◽  
Angle Of Attack ◽  
Aerodynamic Coefficients ◽  
Computational Fluid Dynamics Cfd

This work presents the studies  obtained using OpenFOAM OpenSource Computational Fluid Dynamics (CFD) Software. Experiments were performed to predict lift coefficient and drag coefficient curves for the NACA2412 profile. Subsequently, the results obtained were compared with the results of the bibliography and discussed.

Aerodynamic Analysis of a Vehicle Tanker

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Ramon Miralbes Buil ◽  
Luis Castejon Herrer
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Coefficient ◽  
Aerodynamic Drag ◽  
Positive Impact ◽  
Aerodynamic Resistance ◽  
Independent Contribution ◽  
Aerodynamic Drag Coefficient ◽  
Computational Fluid Dynamics Cfd ◽  
Selection Of

The aim of this article is the presentation of a series of aerodynamic improvements for semitrailer tankers, which reduce the aerodynamic resistance of these vehicles, and, consequently, result in a positive impact on fuel consumption, which is substantially reduced (up to 11%). To make the analysis the computational fluid dynamics (CFD) methodology, using FLUENT, has been used since it allows simulating some geometries and modifications of the geometry without making physical prototypes that considerably increase the time and the economical resources needed. Three improvements are studied: the aerodynamic front, the undercarriage skirt, and the final box adaptor. First they are studied in isolation, so that the independent contribution of each improvement can be appreciated, while helping in the selection of the most convenient one. With the aerodynamic front the drag coefficient has a reduction of 6.13%, with the underskirt 9.6%, and with the boat tail 7.72%. Finally, all the improvements are jointly examined, resulting in a decrease of up to 23% in aerodynamic drag coefficient.

scholarly journals Hydrodynamic Analysis of Different Finger Positions in Swimming: A Computational Fluid Dynamics Approach

2015 ◽  
Vol 31 (1) ◽  
pp. 48-55 ◽  
Author(s):  
J. Paulo Vilas-Boas ◽  
Rui J. Ramos ◽  
Ricardo J. Fernandes ◽  
António J. Silva ◽  
Abel I. Rouboa ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Coefficient ◽  
Hydrodynamic Force ◽  
Lift Coefficient ◽  
Flow Speed ◽  
Cfd Analysis ◽  
Mean Flow ◽  
Hydrodynamic Analysis ◽  
Computational Fluid Dynamics Cfd

The aim of this research was to numerically clarify the effect of finger spreading and thumb abduction on the hydrodynamic force generated by the hand and forearm during swimming. A computational fluid dynamics (CFD) analysis of a realistic hand and forearm model obtained using a computer tomography scanner was conducted. A mean flow speed of 2 m·s−1was used to analyze the possible combinations of three finger positions (grouped, partially spread, totally spread), three thumb positions (adducted, partially abducted, totally abducted), three angles of attack (a = 0°, 45°, 90°), and four sweepback angles (y = 0°, 90°, 180°, 270°) to yield a total of 108 simulated situations. The values of the drag coefficient were observed to increase with the angle of attack for all sweepback angles and finger and thumb positions. For y = 0° and 180°, the model with the thumb adducted and with the little finger spread presented higher drag coefficient values for a = 45° and 90°. Lift coefficient values were observed to be very low at a = 0° and 90° for all of the sweepback angles and finger and thumb positions studied, although very similar values are obtained at a = 45°. For y = 0° and 180°, the effect of finger and thumb positions appears to be much most distinct, indicating that having the thumb slightly abducted and the fingers grouped is a preferable position at y = 180°, whereas at y = 0°, having the thumb adducted and fingers slightly spread yielded higher lift values. Results show that finger and thumb positioning in swimming is a determinant of the propulsive force produced during swimming; indeed, this force is dependent on the direction of the flow over the hand and forearm, which changes across the arm’s stroke.

scholarly journals ANALISIS AERODINAMIKA PADA BODI MOBIL HEMAT ENERGI LINTANG SAMUDRA MENGGUNAKAN METODE COMPUTATIONAL FLUID DYNAMICS

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Bagus Wahyu Prastyo ◽  
Imam Syafa’at ◽  
Muhammad Dzulfikar
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Coefficient ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Lift Coefficient

Aerodinamika kendaraan merupakan bentuk pergerakan aliran udara yang memberi pengaruh atau menyebabkan gaya kepada benda saat bergerak dengan kecepatan tertentu. Ada beberapa cara untuk mengetahui bentuk aerodinamika kendaraan. Pertama yaitu melakukan eksperimen dengan memasukkan kendaraan pada terowongan angin. Cara kedua yaitu menggunakan software CFD (Computational fluid dynamic). Dengan metode CFD peneliti dapat membuat berbagai bentuk desain tanpa mengeluarkan biaya tambahan. Penelitian ini bertujuan untuk mengetahui aerodinamika serta nilai Drag coefficient (CD) dan Lift coefficient (CL) pada bodi mobil Lintang Samudra. Simulasi dilakukan pada 4 kecepatan aliran udara yaitu 40, 50,60 dan 70 km/h. Simulasi menggunakan model turbulensi k-ɛ dengan intensitas 5%, model tersebut dipilih karena memiliki tingkat error terkecil terhadap validasi dari jurnal simulasi Bammidi dan Murty (2014) sebesar 0,13 %. Didapatkan hasil bodi Lintang Samudra 1 memiliki nilai CD = 0,07598 - 0,07025 dan CL=(-0,00800) – (-0,00837) Pada bodi Lintang Samudra 2 memiliki nilai CD = 0,072451 - 0,067020 dan CL = 0,001395 – 0,000949. Terdapat perbedaan bentuk aliran fluida pada bodi Lintang Samudra 1dan bodi Lintang Samudra 2. Jadi bodi kedua lebih aerodinamis dari bodi pertama. Kata kunci: aerodinamika, bodi, CFD, drag, lift.

Thick Crescent Iced Sub-Conductors Spacing Influence on the Aerodynamic Properties

2013 ◽  
Vol 419 ◽  
pp. 62-66
Author(s):  
Li Jun Ma ◽  
Shu Ying Hao ◽  
Qi Chang Zhang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Wake Flow ◽  
Ice Thickness ◽  
Aerodynamic Coefficient ◽  
Coefficient Variation ◽  
Moment Coefficient ◽  
Aerodynamic Properties

Using computational fluid dynamics software FLUENT analysis and calculation the aerodynamic coefficient of the 28mm ice thickness crescent iced quad-bundle conductors under different spacing. Studies show that aerodynamic coefficient of downwind sub-conductors affected by wake-flow, with the upwind sub-conductors there is always a big difference. With different spacing values, quad-bundle iced conductors in the wake-flow of different effects. Upwind sub-conductors, spacing values have nothing to do with the aerodynamic coefficient. Downwind sub-conductors, drag coefficient in the larger change significantly, moment coefficient variation is relatively small. Sub-conductors spacing has no effect on the lift coefficient.

scholarly journals Swimming Propulsion Forces Are Enhanced by a Small Finger Spread

2010 ◽  
Vol 26 (1) ◽  
pp. 87-92 ◽  
Author(s):  
Daniel A. Marinho ◽  
Tiago M. Barbosa ◽  
Victor M. Reis ◽  
Per L. Kjendlie ◽  
Francisco B. Alves ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Force Production ◽  
Attack Angle ◽  
Propulsive Force ◽  
Drag And Lift ◽  
Back Angle ◽  
Dynamics Analyses

The main aim of this study was to investigate the effect of finger spread on the propulsive force production in swimming using computational fluid dynamics. Computer tomography scans of an Olympic swimmer hand were conducted. This procedure involved three models of the hand with differing finger spreads: fingers closed together (no spread), fingers with a small (0.32 cm) spread, and fingers with large (0.64 cm) spread. Steady-state computational fluid dynamics analyses were performed using the Fluent code. The measured forces on the hand models were decomposed into drag and lift coefficients. For hand models, angles of attack of 0°, 15°, 30°, 45°, 60°, 75°, and 90°, with a sweep back angle of 0°, were used for the calculations. The results showed that the model with a small spread between fingers presented higher values of drag coefficient than did the models with fingers closed and fingers with a large spread. One can note that the drag coefficient presented the highest values for an attack angle of 90° in the three hand models. The lift coefficient resembled a sinusoidal curve across the attack angle. The values for the lift coefficient presented few differences among the three models, for a given attack angle. These results suggested that fingers slightly spread could allow the hand to create more propulsive force during swimming.

scholarly journals Computational Fluid Dynamics (CFD) Simulation on Mixing in T-Shaped Micromixer

2020 ◽  
Vol 932 ◽  
pp. 012006
Author(s):  
S N A Ahmad Termizi ◽  
C Y Khor ◽  
M A M Nawi ◽  
Nurlela Ahmad ◽  
Muhammad Ikman Ishak ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Simulation ◽  
Computational Fluid Dynamics Cfd

A Study on the Performance of Stratified Air Conditioning Design in Assembly Halls – A Case Study at the Dazhi Cultural Center in Taiwan

2013 ◽  
Vol 368-370 ◽  
pp. 599-602 ◽  
Author(s):  
Ian Hung ◽  
Hsien Te Lin ◽  
Yu Chung Wang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Indoor Air ◽  
Air Conditioning ◽  
Cfd Simulation ◽  
Indoor Temperature ◽  
Cultural Center ◽  
Computational Fluid Dynamics Cfd

This study focuses on the performance of air conditioning design at the Dazhi Cultural Center and uses a computational fluid dynamics (CFD) simulation to discuss the differences in wind velocity and ambient indoor temperature between all-zone air conditioning design and stratified air conditioning design. The results have strong implications for air conditioning design and can improve the indoor air quality of assembly halls.

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