scholarly journals Drag Reduction of Passenger Car Using Add-On Devices

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Ram Bansal ◽  
R. B. Sharma

This work proposes an effective numerical model using the Computational Fluid Dynamics (CFD) to obtain the flow structure around a passenger car with different add-on devices. The computational/numerical model of the passenger car and mesh was constructed using ANSYS Fluent which is the CFD solver and employed in the present work. In this study, numerical iterations are completed, and then aerodynamic data and detailed complicated flow structure are visualized. In the present work, a model of generic passenger car was developed using solidworks, generated the wind tunnel, and applied the boundary conditions in ANSYS workbench platform, and then testing and simulation have been performed for the evaluation of drag coefficient for passenger car. In another case, the aerodynamics of the most suitable design of vortex generator, spoiler, tail plates, and spoiler with VGs are introduced and analysed for the evaluation of drag coefficient for passenger car. The addition of these add-on devices are reduces the drag-coefficient and lift coefficient in head-on wind. Rounding the edges partially reduces drag in head-on wind but does not bring about the significant improvements in the aerodynamic efficiency of the passenger car with add-on devices, and it can be obtained. Hence, the drag force can be reduced by using add-on devices on vehicle and fuel economy, stability of a passenger car can be improved.

2017 ◽  
Vol 15 (1) ◽  
pp. 45
Author(s):  
Awalu Romadhon ◽  
Dana Herdiana

LSU-05 aircraft is one of the unmanned aerial vehicles (UAV), which is being developed by the Aeronautics Technology Center of LAPAN, whose mission is for research, observation, patrol, border surveillance, and investigation of natural disasters. This study aims to determine the effect of vortex generators on the aerodynamic characteristics of the LSU-05 Unmanned Aircraft wing. The method used is a numerical analysis with CFD simulation for predicting aerodynamic characteristics and flow phenomena that occur. The models used are the aircraft wing of the LSU-05 without vortex generator and with vortex generator designed with CATIA software. The simulation is using ANSYS Fluent software to determine changes in the aerodynamic characteristics of the wing after the addition of vortex generators such as the lift coefficient and drag coefficient. The results of the addition of vortex generator on LSU-05 wings are the increasing value of the maximum lift coefficient of the wing which becomes 1,34840 from 1,26450, it increases 0,0839 (6.63%) point, the increasing value of the drag coefficient on the angle of attack from -9⁰ to 11⁰, the decreasing value of the drag coefficient on the angle of attack 12⁰ up to 15⁰ and the increasing stall angle of wing from 11⁰ to 14⁰ or increased by 3⁰ (27,7%). AbstrakPesawat LSU-05 adalah salah satu pesawat tanpa awak (UAV) yang sedang dikembangkan oleh Pusat Teknologi Penerbangan LAPAN, yang mempunyai misi untuk kegiatan penelitian, observasi, patroli, pengawasan perbatasan wilayah, dan investigasi bencana alam. Penelitian ini bertujuan untuk mengetahui pengaruh penambahan vortex generator terhadap karakteristik aerodinamika dari sayap Pesawat Tanpa Awak LSU-05. Metode yang digunakan adalah analisis numerik dengan simulasi CFD untuk memprediksi karakteristik aerodinamika dan fenomena aliran yang terjadi. Model yang digunakan adalah sayap pesawat LSU-05 tanpa vortex generator dan dengan vortex generator yang didesain dengan software CATIA. Simulasi menggunakan software ANSYS Fluent untuk mengetahui perubahan karakteristik aerodinamika sayap setelah penambahan vortex generator seperti koefisien lift dan koefisien drag. Hasil yang diperoleh dari penelitian penambahan vortex generator pada sayap Pesawat LSU-05 adalah peningkatan nilai koefisien lift maksimum sayap dari 1,26450 menjadi 1,34840 atau naik sebesar 0,0839 (6,63%), peningkatan nilai koefisien drag pada sudut serang -9⁰ s/d 11⁰, penurunan nilai koefisien drag pada sudut serang 12⁰ s.d 15⁰ dan peningkatan sudut stall sayap dari 11⁰ menjadi 14⁰ atau naik sebesar 3⁰ (27,7 %).


Author(s):  
Eiman B Saheby ◽  
Xing Shen ◽  
Anthony P Hays ◽  
Zhang Jun

This study describes the aerodynamic efficiency of a forebody–inlet configuration and computational investigation of a drone system, capable of sustainable supersonic cruising at Mach 1.60. Because the whole drone configuration is formed around the induction system and the design is highly interrelated to the flow structure of forebody and inlet efficiency, analysis of this section and understanding its flow pattern is necessary before any progress in design phases. The compression surface is designed analytically using oblique shock patterns, which results in a low drag forebody. To study the concept, two inlet–forebody geometries are considered for Computational Fluid Dynamic simulation using ANSYS Fluent code. The supersonic and subsonic performance, effects of angle of attack, sideslip, and duct geometries on the propulsive efficiency of the concept are studied by solving the three-dimensional Navier–Stokes equations in structured cell domains. Comparing the results with the available data from other sources indicates that the aerodynamic efficiency of the concept is acceptable at supersonic and transonic regimes.


2018 ◽  
Vol 172 ◽  
pp. 01003
Author(s):  
R Vishwa Krishna. ◽  
R Suwathy. ◽  
M Pragadeesh. ◽  
M Venkatesan.

Trucks are heavy load vehicles used mainly for commercial transport operations. There are several classes of heavy duty commercial vehicles classified based on the weight loaded. More than 50% of the engine output power in such trucks is utilized to overcome the drag. Drag force in automobiles is the resistance offered by air on vehicles at higher speeds. Class 8 trucks suffer higher drag when compared to other classes. In the present work, a numerical model is developed using a commercial code ANSYS FLUENT to predict the drag coefficient value. The effects of gap width and cab front radius with a constant fairing is analysed using the numerical model developed. A Class 8 model truck with minimal drag coefficient having constant fairing and optimized gap width between the trailer and cab is proposed.


Author(s):  
M.K. Padmanabhan ◽  
G. Santhoshkumar ◽  
Praveen Narayan ◽  
N. Jeevaraj ◽  
M. Dinesh ◽  
...  

There are various configurations and parameters that contribute to the Design of Unmanned Aerial Vehicles for specific applications. This paper deals with an innovative design of an unmanned aerial vehicle for a specified class of UAVs that require demands such as long endurance, minimized landing space with vertical take-off and landing (VTOL) capabilities. The focal point of this design is superimposing the high endurance blended wing design into tri-copter to address these parameters. The preliminary calculations are initially performed for the blended wing VTOL vehicle based on the required payload capacity and endurance. Superimposing the tri-copter will decrease the aerodynamic efficiency of the vehicle. Computational fluid dynamics (CFD) is a branch of fluid mechanics that uses numerical methods and algorithms to solve complex problems involving fluid flow which will effectively employed to reduce the cost and time during the conceptual and preliminary design stages. CFD analysis was carried out to estimate the major parameters like lift, drag, lift coefficient (CL) and drag coefficient (CD) for various Angle of Attack (AoA) for configurations of blended wing vehicle with and without tri-copter system in the cruise condition. Thus, the vehicle design and propulsion system is effectively optimized using this drag estimation.


2021 ◽  
Vol 49 (2) ◽  
pp. 395-400
Author(s):  
Manthan Patil ◽  
Rajesh Gawade ◽  
Shubham Potdar ◽  
Khushabu Nadaf ◽  
Sanoj Suresh ◽  
...  

Flow over a conventional delta wing has been studied experimentally at a subsonic flow of 20 m/sec and the flow field developed at higher angle of attack varying from 10° to 20° has been captured. A vortex generator is mounted on the leeward surface of the delta wing and its effect on the flow field is studied. The set of wing tip vortices generated over the delta wing is captured by the oil flow visualization and the streamline over the delta wing surface captured with and without a vortex generator are compared. Based on the qualitative results, the effect of the vortex generator on the lift coefficient is anticipated. Further, force measurement is carried out to quantitatively analyze the effect of vortex generator on the lift and drag coefficient experienced by the delta wing and justify the anticipation made out of the qualitative oil flow visualization tests. In the present study, the effect of mounting of a vortex generator is found to be minimal on the lift coefficient experienced by the delta wing. However, a significant reduction in the drag coefficient with increase in angle of attack was observed by mounting a typical vortex generator.


2020 ◽  
Vol 01 (02) ◽  
pp. 29-36
Author(s):  
Md Rhyhanul Islam Pranto ◽  
Mohammad Ilias Inam

The aim of the work is to investigate the aerodynamic characteristics such as lift coefficient, drag coefficient, pressure distribution over a surface of an airfoil of NACA-4312. A commercial software ANSYS Fluent was used for these numerical simulations to calculate the aerodynamic characteristics of 2-D NACA-4312 airfoil at different angles of attack (α) at fixed Reynolds number (Re), equal to 5×10^5 . These simulations were solved using two different turbulence models, one was the Standard k-ε model with enhanced wall treatment and other was the SST k-ω model. Numerical results demonstrate that both models can produce similar results with little deviations. It was observed that both lift and drag coefficient increase at higher angles of attack, however lift coefficient starts to reduce at α =13° which is known as stalling condition. Numerical results also show that flow separations start at rare edge when the angle of attack is higher than 13° due to the reduction of lift coefficient.


2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Moloud Arian Maram ◽  
Hamid Reza Ghafari ◽  
Hassan Ghassemi ◽  
Mahmoud Ghiasi

This paper is presented on the tandem two-dimensional hydrofoils with profiles NACA4412 in single-phase and two-phase flow domains for different submergence depths and different distances in a various angle of attack (AoA). Also, supercavitation is studied at σ = 0.34 by the Zwart cavitation model. Reynolds-averaged Navier–Stokes (RANS) with the shear stress transport (SST) K-ω is employed as a turbulence model in transient analysis of Ansys FLUENT software. The numerical results show that, by increasing depth, the drag coefficient increases for both hydrofoils 1 and 2 as well as the lift coefficient. The drag coefficient of hydrofoil 2 is bigger than hydrofoil 1 for all depths; moreover, it was found that the flow pressure behind the hydrofoil 1 had affected the upper and the lower surface of the hydrofoil 2 at each distance or AoA. These effects are observed in the hydrofoil 2 lift coefficient as well as the flow separation. However, the maximum lift-to-drag ratio is observed at AoA =  8 ° and 3.5c distance. Also, single-phase results reveal that the value of pressure and the hydrodynamic coefficient are very different from the two-phase flow results, due to the elimination of the free surface. So, a two-phase flow domain is recommended for increasing the accuracy of results. In addition, the investigation of supercavitation shows a growth in cavity occurrence on the surface by raising AoA.


2021 ◽  
Author(s):  
Scott Lindsay

Upper surface flaps commonly referred to as spoilers or drag brakes can increase maximum lift, and improve aerodynamic efficiency at high, near-stall angles of attack. This phenomenon was studied experimentally and computationally using a 0.307626 m chord length NACA 2412 airfoil in six different configurations, and one baseline clean configuration. A wind tunnel model was placed in the Ryerson Low Speed Wind Tunnel (atmospheric, closed-circuit, 3 ft × 3 ft test section) at a Reynold’s number of approximately 780,000 and a Mach number of 0.136. The wind tunnel study increased the lift coefficient by 0.393%-2.497% depending on the spoiler configuration. A spoiler of 10% chord length increased the maximum lift coefficient by 2.497 % when deflected 8º, by 2.110% when deflected 15º, and reduced the maximum lift coefficient by 2.783% when deflected 25º. A spoiler of 15% chord length produced smaller maximum lift coefficient gains; 0.393% when deflected 8º, by 1.760% when deflected 15º, and reduced the maximum lift coefficient by 4.475% when deflected 25º. Deflecting the spoiler increased the stall angle between 37.658% and 87.544% when compared with the clean configuration. The drag coefficient of spoiler configurations was lower than the clean configuration at angles of attack above 18º. The combination of the increased lift and reduced drag at angles of attack above 18º created by the spoiler configurations resulted in a higher aerodynamic efficiency than the clean configuration case. A 10% chord length spoiler deflected at 8º produced the highest aerodynamic efficiency gains. At low angles of attack, the computational study produced consistently higher lift coefficients compared with the wind tunnel experiment. The lift-slope was consistent with the wind tunnel experiment lift-slope. The spoiler airfoil stall behaviour was inconsistent with the results from the wind tunnel experiment. The drag coefficient results were consistent with the wind tunnel experiment at low angles of attack. However, the spoiler equipped airfoils did not reduce drag at high angles of attack. Therefore, the computational model was not valid for the spoiler configurations at high angles of attack.


2021 ◽  
Author(s):  
Scott Lindsay

Upper surface flaps commonly referred to as spoilers or drag brakes can increase maximum lift, and improve aerodynamic efficiency at high, near-stall angles of attack. This phenomenon was studied experimentally and computationally using a 0.307626 m chord length NACA 2412 airfoil in six different configurations, and one baseline clean configuration. A wind tunnel model was placed in the Ryerson Low Speed Wind Tunnel (atmospheric, closed-circuit, 3 ft × 3 ft test section) at a Reynold’s number of approximately 780,000 and a Mach number of 0.136. The wind tunnel study increased the lift coefficient by 0.393%-2.497% depending on the spoiler configuration. A spoiler of 10% chord length increased the maximum lift coefficient by 2.497 % when deflected 8º, by 2.110% when deflected 15º, and reduced the maximum lift coefficient by 2.783% when deflected 25º. A spoiler of 15% chord length produced smaller maximum lift coefficient gains; 0.393% when deflected 8º, by 1.760% when deflected 15º, and reduced the maximum lift coefficient by 4.475% when deflected 25º. Deflecting the spoiler increased the stall angle between 37.658% and 87.544% when compared with the clean configuration. The drag coefficient of spoiler configurations was lower than the clean configuration at angles of attack above 18º. The combination of the increased lift and reduced drag at angles of attack above 18º created by the spoiler configurations resulted in a higher aerodynamic efficiency than the clean configuration case. A 10% chord length spoiler deflected at 8º produced the highest aerodynamic efficiency gains. At low angles of attack, the computational study produced consistently higher lift coefficients compared with the wind tunnel experiment. The lift-slope was consistent with the wind tunnel experiment lift-slope. The spoiler airfoil stall behaviour was inconsistent with the results from the wind tunnel experiment. The drag coefficient results were consistent with the wind tunnel experiment at low angles of attack. However, the spoiler equipped airfoils did not reduce drag at high angles of attack. Therefore, the computational model was not valid for the spoiler configurations at high angles of attack.


Author(s):  
Sivaraj Gopal Krishnan ◽  
Mohammad Hafifi Ishak ◽  
Mohammad Azwan Nasirudin ◽  
Farzad Ismail

This work describes the aerodynamic characteristics of an aircraft wing model with a Rüppell’s griffon vulture (RGV)-type winglet. A computational fluid dynamics (CFD) study using ANSYS 15.0 was conducted to study the effect of the RGV winglet on a rectangular wing. The NACA 65(3)-218 wing consists of 660 mm span and 121 mm chord length where the aspect ratio is 5.45. Eight different winglet configurations have been studied. Furthermore, the study is extended to study effect of cant angle and different angles of attack (AOA) to the winglet. A comparative study is done on aerodynamic features such as lift coefficient (CL), drag coefficient (CD), lift/drag ratio (CL/CD) and tip vortices to get the best RGV winglet design. The RGV winglet achieved highest CL compared to other types of winglets configuration. Based on contour plot analysis, the RGV winglet shows lower vortex formation compared to without winglet. The results show about 15 to 30% reduction in drag coefficient and 5 to 25% increase in lift coefficient by using an RGV winglet.


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