Browse Topic: Spoilers
Helicopter tail shake constitutes a significant limitation to both passenger comfort and aircraft stability. Under powered descent conditions, elevated Angle of Attack (AoA) cause flow separation around the rotor hub and engine cowling, leading to the development of an unsteady wake dominated by large-scale turbulent structures. To support the helicopter tail shake phenomenon investigation, a dedicated Particle Image Velocimetry (PIV) experimental setup was designed in this work, together with four aerodynamic devices aimed at mitigating tail shake. These components were then tested through a wind tunnel campaign with the PIV setup. The proposed aerodynamic components were conceived to either deflect the hub wake away from the tail empennages or to decrease the Turbulent Kinetic Energy (TKE) within the wake. To achieve these objectives, a dorsal fin, a horse-collar, and two spoiler configurations inspired by automotive applications were designed and experimentally evaluated. The devices were tested both as standalone solutions and in combined arrangements on a scaled helicopter wind tunnel model featuring a rotating hub and blade shanks. The vertical velocity component, was used as an indicator of wake deflection, and the Turbulent Kinetic Energy was used as an indicator of wake turbulence. The Horse Collar and the Large Spoiler showed a reduction in both indicators suggesting possible tail shake mitigating capabilities, and additional improvements were achieved when the two devices were deployed in combination.
MSIL (Maruti Suzuki India Limited), India’s leading automotive manufacturer, offers a diverse range of SUVs (Sports Utility Vehicles) in its portfolio. Traditionally, SUVs are associated with an assertive stance and a commanding road presence; however, this bold design language often compromises aerodynamic drag performance. Over the past decade, demand for this segment has surged, while CAFE (Corporate Average Fuel Economy) regulations have become increasingly stringent. To address this growing market need, MSIL conceptualized a new SUV - Victoris - targeted to deliver best-in-class aerodynamic efficiency in MSIL SUV portfolio. This paper details the aerodynamic development process using CFD (Computational Fluid Dynamics) and full-scale WTT (Wind Tunnel Testing). Initially, the aggressive styling of Victoris negatively impacted drag performance. Strategic exterior surface refinements and integration of aero components enabled recovery of aerodynamic efficiency. Key interventions included redesigned front and rear bumpers, roof-end treatment, quarter spoiler profiling, bumper corner vents, and aero-cut alloy wheels. Victoris successfully retained its bold styling while meeting ambitious aerodynamic targets. The optimized aerodynamic silhouette comprising hood-to-windshield transition, roof contouring, backdoor spoiler, and side body profiling - along with underbody elements such as covers, strakes, and air curtains improved drag performance by 14% compared to the initial design. Achieving this improvement required significant shape modifications and aero part additions without compromising SUV identity. This paper explains how these measures were implemented and the resulting airflow characteristics.
In today's dynamic driving environments, reliable rear wiping functionality is essential for maintaining safe rearward visibility. This study sharing the next-generation rear wiper motor assembly that seamlessly integrates the washer nozzle, delivering improved performance alongside key benefits such as better Buzz, Squeak, and Rattle (BSR) characteristics, reduced system complexity, cost savings, and enhanced perceived quality. This integrated design simplifies the hose routing which improves the compactness and the efficiency of the design. This also enhances the spray coverage and minimizes the dry wiping unlike the traditional systems that position the washer nozzle separately. A non-return valve (NRV) is incorporated to eliminate spray delays ass it maintains consistent water flow giving cleaning effectiveness. Since this makes the nonfunctional parts completely leak proof due to the advanced sealing, it increases the durability and reliability in long run. As this proposal offers a sustainable solution, it can be considered as the new benchmark in rear wiper technology.
The current Range Rover is the fifth generation of this luxury SUV. With a drag coefficient of 0.30 at launch, it was the most aerodynamically efficient luxury SUV in the world. This aerodynamic efficiency was achieved by applying the latest science. Rear wake control was realised with a large roof spoiler, rear pillar and bodyside shaping, along with an under-floor designed to reduce losses over a wide range of vehicle configurations. This enabled manipulation of the wake structure to reduce drag spread, optimising emissions measured under the WLTP regulations. Along with its low drag coefficient, in an industry first, it was developed explicitly to achieve reduced rear surface contamination with reductions achieved of 70% on the rear screen and 60% over the tailgate when compared against the outgoing product. This supports both perceptions of luxury along with sensor system performance, demonstrating that vehicles can be developed concurrently for low drag and reduced rear soiling. This paper describes the development journey of the car, from initial phases extensively exploiting simulation through to testing pre-production prototype vehicles in both FKFS Aeroacoustic and Thermal Wind Tunnels.
MSIL (Maruti Suzuki India Limited), India’s leading carmaker, has various SUVs (Sports Utility Vehicle) in its model lineup. Traditionally, SUVs are considered to have a bold on-road presence and this bold design language often deteriorates aerodynamic drag performance. Over the years, the demand for this segment has significantly grown, whereas the CAFE (Corporate Average Fuel Economy) norms have become more stringent. To cater this growing market demand, MSIL planned for two new SUVs: (1) New BREZZA - A bolder design with similar targeted aerodynamic performance compared to its predecessor (BREZZA-2016) and (2) FRONX - A new cross-over SUV vehicle targeted best-in-class aerodynamic performance in this category at MSIL. This paper illustrates the aerodynamic development process for these two SUVs using CFD (Computational Fluid Dynamics) and full scale WTT (Wind Tunnel Test). During the initial stages, the bolder design of the New BREZZA (2022) deteriorated the aerodynamic drag of the vehicle. Styling exterior surface modifications and addition of new aero parts facilitated the recovery of aerodynamic drag performance. The front & rear bumper corners, roof end spoiler profile, rear quarter glass edging, slits on fender lining and air-dam on rear bumper helped in air flow attachment. In FRONX, the styling design language had been created by considering ambitious aerodynamic performance requirements. The aerodynamic silhouette consisting of hood-windshield transition, roof lining, optimized backdoor spoiler, side body profile etc. along with underbody aero-parts like underbody covers, strakes and central air-dam improved the aerodynamic efficiency in FRONX by 11% with respect to base model BREZZA-2016. To achieve this improvement in aerodynamic drag values, major technical counter measures in external shape and addition of aero parts while retaining the SUV styling image were done. This paper illustrates how these changes were realized in the aerodynamic development process and the corresponding air flow phenomenon.
Enhancing aerodynamic performance is vital for reducing battery weight and cost, and for boosting the range of the vehicle. Aerodynamics in electric vehicles is crucial at highway speeds as over 50 percent of energy is spent on pushing the air away. The optimization of drag and lift is carried out with the addition of aerodynamic accessories that include an air dam and a rear spoiler using computational fluid dynamic model. The rear spoiler is used to diminish the amount of drag force and create downforce on the body of an electric vehicle. Additionally, the rear spoiler’s angle is varied, and a comparative study of the vehicle’s drag and lift forces is performed. The addition of an air dam created additional down force on the vehicle, resulting in improved traction and stability. The air dam also creates a local high-pressure air zone that is used to direct airflow to the battery and evenly cool it. This is accomplished using a hexagonal honeycomb structure, which creates a uniform, streamlined flow of air to the car’s underbody. Along with the honeycomb structures, fins were employed at the base of the battery, which enhanced the rate of convective heat from the battery to the air outside, resulting in improved air cooling of the battery. Diffusers were used at the rear of the vehicle to compensate for the higher drag resistance generated by the fins. This not only increases the battery’s life and performance but also improves the range of the electric vehicle by an appreciable amount.
In modern conditions, the rising cost of fuel and the adoption of more stringent environmental standards in developed countries require a reduction in fuel consumption by vehicles. The profitability of the trucking industry depends on the fuel economy of trucks, which, in turn, is determined by many factors, including their aerodynamic characteristics. The article substantiates new ways of reducing the aerodynamic drag of road trains based on a study conducted by the authors. Numerical simulation of the road train aerodynamics allows us to determine the distribution of velocity, pressure, and air turbulence zone around it. The effectiveness of known and proposed technical solutions to reduce the aerodynamic drag of trains with the use of spoilers of various designs has been evaluated and implemented. An effective way to reduce the aerodynamic resistance of road trains is proposed. The method is to use air ducts as a part of the semi-trailer through which air flows in from the front and around it, along and through the sides. By means of numerical modeling, the features of the distribution of turbulent dissipation zones of the airflow and its velocity in the rarefaction zone behind the semi-trailer (RZBS) are established. The obtained results confirm the feasibility of the application of the proposed method to reduce the aerodynamic drag of road trains.
Aerodynamic forces that act on a vehicle play a critical role in impacting the vehicle longitudinal dynamics, particularly stopping distance and time during vehicle braking. Currently, many vehicles use a rear spoiler to enhance the vehicle aerodynamic performance. In vehicles equipped with an active rear spoiler, a mechanism is used to control the spoiler angle of attack, based on various inputs and parameters. This article investigates the impact of an active rear spoiler, with a variable angle of attack, on both the vehicle aerodynamic forces and longitudinal braking dynamics, such as braking stopping distance and time. A two-dimensional (2D) computational fluid dynamics (CFD) model, using ANSYS-Fluent®, is employed to estimate the impact of the angle of attack of the rear spoiler on the vehicle aerodynamic forces (lift and drag forces) for comparison with a vehicle lacking a spoiler. Furthermore, the CFD results are used as inputs in a realistic vehicle braking mathematical model to estimate the vehicle stopping distance and time at different spoiler angles of attack, and the obtained results are compared to the case of the vehicle that is not equipped with a spoiler. The proposed vehicle model, which includes the vehicle aerodynamic forces, is simulated using MATLAB/Simulink®. The simulation results demonstrate that the vehicle rear spoiler has a clear impact on the vehicle braking distance and time, especially at high vehicle speeds. Based on the simulation results, novel 2D maps, which relate the vehicle stopping distance and time to the angle of attack of the vehicle rear spoiler, are presented. These maps can be used as a good basis for estimating the optimal spoiler angle of attack for vehicle braking at different initial speeds and, hence, can provide significant help in the design of an optimal braking system controller for the vehicle.
The main goal of race car aerodynamics is to generate a desired intensity of downforce for the least possible amount of drag. Nonetheless, the balance of the forces under all circumstances due to speed and acceleration is equally important. The modeling was performed using SolidWorks, and the analysis was done both analytically and by means of computational fluid dynamics (CFD) using a flow simulation with STAR-CCM+. The aerodynamics package, which includes the rear wing, front wing, and undertray that help in faster cornering, is analyzed in the full-car analysis. The full-car analysis is done for pitch and yaw. The increase in cornering ability can come from two major aspects: an increase in the aerodynamic downforce and a decrease in the aerodynamic drag of the vehicle. In order to implement the desired aerodynamics package, an airfoil with a predefined profile was selected. The main factor that limits the selection of an airfoil is its effectiveness at low velocities. Several airfoils suitable for low-velocity applications were considered. This thesis will hence define the design parameters of a rear wing that classifies as an aerodynamic device.
Aerodynamics of a car plays a very important role in a racing car. That is why many race cars are designed to take advantage of aerodynamics. Improvement of cornering speed in the race car is achieved through increase in the downforce on the tire. Spoilers (inverted wings) are used for increasing the downforce but this increases the drag too. The performance of a racing car depends on both the downforce and the drag, requiring good compromise between these two forces. In this paper, different airfoils which are used for building the front and rear spoiler of the race car are analyzed. NACA 0012 is analyzed at 0° angle of attack. The front spoiler design is made on the basis of the result with the analysis of S1223 (s1223-il) and GOE304 at 10° and 17°. Modeling of a wing has been done in Solid work and CFD analysis using ANSYS software.
Aerodynamic technologies for light-duty vehicles were evaluated through full-scale testing in a large low-blockage closed-circuit wind tunnel equipped with a rolling road, wheel rollers, boundary-layer suction and a system to generate road-representative turbulent flow. This work was part of a multi-year, multi-vehicle study commissioned by Transport Canada and Environment and Climate Change Canada, and carried out in cooperation with the US EPA, to support the evaluation of light-duty-vehicle greenhouse-gas-emission regulations. A 2016 paper reported drag-reduction measurements for technologies such as active grille shutters, production and custom underbody treatments, air dams, ride height control and combinations of these. This paper describes an extension to that work and addresses vehicle aerodynamics in three ways. First, whole vehicle body-shaping changes were evaluated by adding older or newer generation models, representing distinct body style redesigns, of select vehicles of different classes from the 2016 study. Second, newer vehicles were added to represent the market application of advanced aerodynamics in terms of body shaping and drag-reduction technologies. Third, drag reduction over a range of yaw angles is reported for new technologies such as side-mirror removal (for replacement with camera systems) and air curtains. This paper focuses specifically on drag measurements, complementing a 2019 paper which focused on relating mean surface, wake and underbody pressure measurements to aerodynamic drag for a selection of the test vehicles. The most effective redesign of a vehicle was found to reduce the wind-averaged drag area by 9% compared to the previous model. The best commercial or idealized applications of the top performing technologies, namely ride height control, underbody panels and active grille shutters, provided wind-averaged drag area reductions in the 6% to 8% range. Idealized technologies performed better than their commercial counterparts. The best applications of other technologies like side mirror removal and OEM air dams were in the range of 3% to 5% reduction in wind-averaged drag area. All OEM air curtains performed better when combined with ride height reduction but still only reduced wind-averaged drag area by around 1% in the best case. The complete range of results, yaw effects and comparison with previously published results are presented and discussed in this paper.
The present numerical analysis aims at studying the effect of changes in profile of truck-trailer on aerodynamic drag and its adverse effect on fuel consumption. The numerical analysis is carried out using commercial CFD software, ANSYS Fluent, with k-ω Shear tress transportation (SST) turbulence model. In present study four models of truck were analysed, including baseline model at different Reynolds numbers, namely 0.5, 1, 1.5 and 2 million. In order to enhance fuel consumption, various profile modifications have been adapted on baseline truck-trailer model by adding a spoiler and bottom diffuser at the rear of the truck, by providing vortex generator at the rear top of the truck and by adding boat tail at the end of trailer. The comparison has been done with respect to coefficient of drag, coefficient of pressure, pressure contours, and velocity vectors between all four cases. It is observed from the simulation results among different modifications of truck, adding of boat tail at the rear end of truck gives the maximum reduction in aerodynamic drag of 34.28 % as compared to baseline model, which reduces the fuel consumption by 20.57% at a speed of 82 km/h.
Due to the increasingly stringent environmental regulations all around the world confronted by exhaust emission and energy consumption, improving fuel economy has been the top priority for most automotive manufacturers. In this context, the basic process for vehicle shape development has evolved into optimizing the design to achieve better aerodynamic characteristics, especially drag reduction. Of all the optimization approaches, the gradient-based adjoint method has currently received extensive attention for its high efficiency in calculating the objective sensitivity with respect to geometry parameters, which is the first and foremost step for subsequent shape modification. In this work, the main goal is to explore the adjoint method through optimizing the vehicle shape for a lower drag based on a production SUV. Firstly, the influence of different mesh schemes was discussed on sensitivity prediction of aerodynamic drag. Secondly, according to the sensitivity distribution, several key areas, like the side mirrors, A pillars, air dam, and rear lamps, were respectively altered through mesh morphing process. Furthermore, the optimized effect was validated by steady as well as transient simulation. Steady Reynolds Averaged Navier Stokes (RANS) approach was used for the primal flow solution of adjoint calculations, while transient simulation with Stress Blended Eddy Simulation (SBES) was also performed on the baseline and the optimized vehicle for more detailed flow field structure. The overall drag reduction is approximately 8counts for steady result, and 10counts for unsteady solution. Finally, the drag reduction effect of the optimized side mirrors and air dam was correlated with full-scale wind tunnel test. This paper evaluates the effectiveness of adjoint method for aerodynamic optimization of a production vehicle, which indicates more extensive and promising application of this approach in the early stage of vehicle development for its high efficiency as well as strong robustness.
Formula SAE vehicles, like many other vehicles within motorsport, often employ rear mounted aerodynamic devices to improve cornering performance, these devices can however have a significant amount of aerodynamic drag. Additional speed can be gained by reducing the impact of the rear wing on the straightaways of the track through the use the aptly named Drag Reduction System (DRS), which works by reducing the angle of attack of the rear wing flap(s). A DRS can however introduce other performance losses, including the losses from having a gap between the rear wing flaps and endplate to prevent friction, the potential to stall the rear wing from improper opening angles of the flaps, and from the wake of the DRS actuator if positioned in front of the airfoils. An additional concern is the time it takes for the rear wing performance to return upon DRS deactivation, which will affect how long before corner entry the driver must disable the system. Insight into each of these problems as well as the optimum opening angles was found through the use of CFD using Siemens’ STAR-CCM+ 2019.1. Simplified geometry came from UMSAE Polar Bear Racing’s car, PBR20, out of the University of Manitoba. All steady state simulations were done using RANS, while the DRS deactivation study was done using a novel method using Detached Eddy Simulation (DES), where dynamic overset meshes were used to model the transient motion of the flaps. As a result of the deactivation study, new insight was gained into the dynamic behaviour of drag reduction systems.
Based on the first sedan of the LYNK&CO brand from Geely, the high-performance configuration equipped with an additional aerodynamic package was developed. The aerodynamic package including front wheel deflectors, front lip, side skirts, rear spoiler, and rear diffuser, was required to be upgraded to generate enough aerodynamic downforce for better handling stability, without compromising the aerodynamic drag of the vehicle too much to keep a low fuel consumption. Starting from the baseline configuration of the aerodynamics package provided by the design studio, the components were optimized for aerodynamic drag and lift using the simulation approach with PowerFLOW in combination with a design space exploration method. As a result, the targets for the aerodynamic coefficients of the vehicle and in particular a good trade-off between lift and drag were achieved. Wind tunnel testing was involved to calibrate the simulation results at the beginning and to validate the optimized design at the end of the aerodynamic development. A consistently good agreement between the simulation and experiment was achieved.
This paper details an aeroelastic concept for an adaptive and passive wing, which is primarily aimed for use within the automotive sector to reduce drag and fuel emissions. The work will also be of interest in the motorsport sector to improve performance and also some applications within the aerospace and renewable energy sectors. The wind tunnel testing of a spring-mounted symmetrical NACA 0012 wing in freestream is studied over 0° to 40° angles of incidence. General operation of the concept is verified at low angles in the pre-stall region with that of a theoretical estimation using finite and infinite wings. Three distinct regions are identified, pre-stall, near-stall, and post-stall. The transient limitations associated in the near-stall region with variations in spring loading and flow velocities are discovered. It is identified as a periodic self-sustained oscillation with nondimensional reduced frequencies in the range from 0.14 to 0.22. Furthermore, performance in the post-stall region along with pre-stall is reported, and methods for the adjustment of the elastic element for a desired response are introduced. Evaluation is conducted with regard to an automotive application such as a rear wing on a high-downforce race car. Typically a 25% increase in wind velocity in the pre-stall region results in a 3° to 5° change in angle of incidence corresponding to a 25-40% reduction of drag coefficient depending on spring stiffness. Reductions of 20° in angle of incidence with similar 25% increase in wind velocity are typically found in the post-stall region. Even larger reductions are found when transitioning through the stall region. This work provides a valuable insight for a novel concept, but we only recommend its use in the pre-stall region to achieve steady results. Use at higher angles is only recommended if transient effects are not important. Limitations to this proof of concept work are highlighted and future development work is suggested to achieve further increases in performance.
A multi-year, multi-vehicle study was conducted to quantify the aerodynamic drag changes associated with drag reduction technologies for light-duty vehicles. Various technologies were evaluated through full-scale testing in a large low-blockage closed-circuit wind tunnel equipped with a rolling road, wheel rollers, boundary-layer suction and a system to generate road-representative turbulent winds. The technologies investigated include active grille shutters, production and custom underbody treatments, air dams, wheel curtains, ride height control, side mirror removal and combinations of these. This paper focuses on mean surface-, wake-, and underbody-pressure measurements and their relation to aerodynamic drag. Surface pressures were measured at strategic locations on four sedans and two crossover SUVs. Wake total pressures were mapped using a rake of Pitot probes in two cross-flow planes at up to 0.4 vehicle lengths downstream of the same six vehicles in addition to a minivan and a pick-up truck. A smaller rake was used to map underbody total pressures in one cross-flow plane downstream of the rear axle for three of these vehicles. The results link drag reduction due to various technologies with specific changes in vehicle surface, rear underbody and wake pressures, and provide a database for numerical studies. In particular, the results suggest that existing or idealized prototype technologies such as active grille shutters, sealing the external grille and ride height control reduce drag by redirecting incoming flow from the engine bay or underbody region to smoother surfaces above and around the vehicle. This mechanism can enhance the reduction in wheel drag due to reduced wheel exposure at lowered ride height. Sealing the external grille was found to redirect the flow more efficiently than closing the grille shutters, and resulted in greater drag reduction. Underbody treatments were also found in some cases to redistribute the flow around the vehicle to reduce pressure drag in addition to underbody friction drag. The magnitude and spatial extent of the measured pressure changes due to the various technologies were often consistent with the amount of drag reduction.
An electric vehicle (EV) has less powertrain energy loss than an internal combustion engine vehicle (ICE), so its aerodynamic accounts have a larger portion of drag contribution of the total energy loss. This means that EV aerodynamic performance has a larger impact on the all-electric range (AER). Therefore, the target set for the aerodynamics development for a new EV hatchback was to improving AER for the customer’s benefit. To achieve lower aerodynamic drag than the previous model’s good aerodynamic performance, an ideal airflow wake structure was initially defined for the new EV hatchback that has a flat underbody with no exhaust system. Several important parameters were specified and proper numerical values for the ideal airflow were defined for them. As a result, the new EV hatchback achieves a 4% reduction in drag coefficient (CD) from the previous model. A wind tunnel with a 0 degree yaw angle is generally used in new vehicle development, but this condition is different from the real world with a small yaw angle due to natural crosswinds. The new EV hatchback was also examined under a small yaw angle (4 degree) condition for practical use, and some crosswind sensitivity measures were applied. The mechanism causing an increase in aerodynamic drag was studied by observing asymmetrical airflow during the development process. Attention was focused on negative pressure growth, which is the root cause of leading aerodynamic drag from the rear end wake. To control the wake, the rear side spoiler shape was optimized. As a whole, considering the tendency that the difference in the 0 and 4 degree CD becomes larger for vehicles with a better CD, the aerodynamic drag increase of the new EV hatchback from a yaw angle of 0 to 4 degrees was concluded to be acceptable in comparison with the previous model.
A modern benchmark for passenger cars - DrivAer model - has provided significant contributions to aerodynamics-related topics in automotive engineering, where three categories of passenger cars have been successfully represented. However, a reference model for high-performance car configurations has not been considered appropriately yet. Technical knowledge in motorsport is also restricted due to competitiveness in performance, reputation and commercial gains. The consequence is a shortage of open-access material to be used as technical references for either motorsport community or academic research purposes. In this paper, a parametric assessment of race car aerodynamic devices are presented into four groups of studies. These are: (i) forebody strakes (dive planes), (ii) front bumper splitter, (iii) rear-end spoiler, and (iv) underbody diffuser. The simplified design of these add-ons focuses on the main parameters (such as length, position, or incidence), leading to easier manufacturing for experiments and implementation in computational studies. Consequently, a proposed model aims to address enclosed-wheel racing car categories, adapting a simplified, 35% scaled-model DrivAer Fastback shape (i.e. smooth underbody, no wheels, and with side mirrors). Experimental data were obtained at the 8 ft x 6 ft Cranfield Wind Tunnel using an internal balance for force and moment measurements. The aerodynamic performance of each group of add-on was assessed individually in a range of ride heights over a moving belt. All cases represent the vehicle at a zero-yaw condition, Reynolds number (car length-based) of 4.2 × 106 and Mach number equal to 0.12. The proposed high-performance configuration (DrivAer hp-F) was tested and a respective Reynolds number dependency study is also provided. In line with the open-access concept of the DrivAer model, the CAD geometry and experimental data will be made available online to the international community to support independent studies.
Today's strict fuel economy requirement produces the need for the cars to have really optimized shapes among other characteristics as optimized cooling packages, reduced weight, to name a few. With the advances in automotive technology, tight global oil resources, lightweight automotive design process becomes a problem deserving important consideration. It is not however always clear how to modify the shape of the exterior of a car in order to minimize its aerodynamic resistance. Air motion is complex and operates differently at different weather conditions. Air motion around a vehicle has been studied quite exhaustively, but due to immense complex nature of air flow, which differs with different velocity, the nature of air, direction of flow et cetera, there is no complete study of aerodynamic analysis for a car. Something always can be done to further optimize the air flow around a car body. Computational Fluid Dynamics (CFD) solvers can be partnered with optimization software which guide model design changes and evaluate the corresponding results. Design changes can be executed by modifying a parameterized geometry or using mesh morphing techniques. In the present paper, ANSYS Fluent will be used in conjunction with the optimization software ANSYS DesignXplorer to study ways of reducing drag and lift for a car body. The body in question in this study is the Ahmed body[1] which has been used numerous times for CFD code validation. This geometry represents a road legal car which is used to study the effect of different forces like, aerodynamic drag force, lift force, and some other major forces which affect a car’s motion significantly. However, after thorough research and application, it has been concluded that a rear spoiler is always beneficial for fast cars, since the car tends to be much stable aerodynamically after the application of the spoiler. However, different angle of the spoiler reacts differently to different air flow conditions. We have modified the Ahmed body by making a few design changes and attaching a Clark-Y foil. Accurate prediction of its aerodynamic performance often requires very accurate and computationally expensive calculations. Optimization of the design will be achieved by using reduced resources, by analyzing how air at different velocity affect the body and what changes might be necessary for a further optimized performance. This paper will demonstrate that optimization can be performed with limited resources relying on information about drag deltas rather than absolute values. Keeping limiting resources in mind, a grid independence study wasn’t done.
Aerodynamics plays a key role in nowadays vehicle development, aiming efficiency on fuel consumption, which leads to a green technology. Several initiatives around the world are regulating emissions and efficiency of vehicles such as EURO for European Marketing and the INOVAR Auto Project to be implemented in Brazil on 2017. In order to meet requirements in terms of performance, especially on aerodynamics, automakers are focusing on aero-efficient exterior designs and also adding deflectors, covers, active spoilers and several other features to meet the drag coefficient. Usually, the aerodynamics properties of a vehicle are measured in both CFD simulations and wind tunnels, which provide controlled conditions for the test that could be easily reproduced. During the real operations conditions, external factors can affect the flow over the vehicle such as cross wind in open highways. The aerodynamic behavior of the vehicle can also be affected by the influence of the user such as by opening the windows in order to cool down the cabin, which is the main topic of this paper. In this work, 12 different window-opening combinations are presented and the drag values compared with a baseline model, considering fully closed windows. The study was conducted using CFD simulations of a current production hatchback vehicle, with two passenger inside and full interior cabin representation. Results show drag increment for all presented cases, compared with baseline configuration, which also implies in fuel consumption increase. Further studies on cabin cooling effects and passenger’s thermal comfort are conducted in order to complement this paper.
Since the Brazilian government established the Inovar-Auto programme in 2012, the automotive industry has pursued tax savings by signing up for the programme. This new plan (from 2013 to 2017) has three main objectives: fortification of the industry and domestic market; increase incentives for investment and innovation; and enhance energy efficiency of vehicles produced in Brazil. For instance, manufacturers can gain up to 2% extra in IPI tax credits (aside 30% from Inovar-Auto achievements) by producing even more fuel-efficient models. In relation to energy efficiency, the aerodynamic drag over a vehicle contributes to the share of energy requested to promote its movement in high speed. Thus, the drag forces are the major reasons of fuel consumption. In this context, this paper presents a profile comparison of Hatch 2015 cars models produced in Brazil, in regards to drag and geometry features as roof end angle, rear slant angle and rear-end spoiler. The 2015 best-seller model of each one of the ten 2014 best-seller manufactures in Brazil are analysed. These ten Hatch 2015 models are: (1st) Fiat Novo Palio, (2nd) Volkswagen Gol, (3rd) Chevrolet Onix, (4th) Hyundai HB20, (5th) Ford New Fiesta, (6th) Renault Sandero, (7th) Toyota Etios, (8th) Citroen C3, (9th) Nissan March, and (10th) Peugeot 208. Therefore, the main contribution of this paper is to compare the bestseller car profiles produced and commercialised in Brazil, in a view of aerodynamic forces and geometry features.
Items per page:
50
1 – 50 of 120