Browse Topic: Spoilers
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
XAM is a two-seat city vehicle prototype developed at the Politecnico di Torino, equipped with a hybrid propulsion system to obtain low consumptions and reduced environmental impact. The design of this vehicle was guided by the requirements of weight reduction and aerodynamic optimization of the body, aimed at obtaining a reduction of resistance while guarantying roominess. The basic shape of the vehicle corresponding to the requirements of style, ergonomics and structure were deeply studied through CFD simulation in order to assess its aerodynamic performance (considering the vehicle as a whole or the influence of the various details and of their changes separately). The most critical areas of the body (underfloor, tail, spoiler, mirrors, A-pillar) were analyzed creating dedicated refinement volumes. The CFD analysis confirmed that the shape of the simplified model, having been created in compliance with the best practices of automotive literature, had a good aerodynamic performance
One of the passive methods to reduce drag on the unshielded underbody of a passenger road vehicle is to use a vertical deflectors commonly called air dams or chin spoilers. These deflectors reduce the flow rate through the non-streamlined underbody and thus reduce the drag caused by underbody components protruding in to the high speed underbody flow. Air dams or chin spoilers have traditionally been manufactured from hard plastics which could break upon impact with a curb or any solid object on the road. To alleviate this failure mode vehicle manufacturers are resorting to using soft plastics which deflect and deform under aerodynamic loading or when hit against a solid object without breaking in most cases. This report is on predicting the deflection of soft chin spoiler under aerodynamic loads. The aerodynamic loads deflect the chin spoiler and the deflected chin spoiler changes the fluid pressure field resulting in a drag change. This fluid structure interaction (FSI) between chin
The new Murano was developed with special emphasis on improving aerodynamics in order to achieve fuel economy superior to that of competitor models. This paper describes the measures developed to attain a drag coefficient (CD) that is overwhelmingly lower than that of other similar models. Special attention was paid to optimizing the rear end shape so as to minimize rear end drag, which contributes markedly to the CD of sport utility vehicles (SUVs). A lower grille shutter was adopted from the early stage of the development process. When open, the shutter allows sufficient inward airflow to ensure satisfactory engine cooling; when closed, the blocked airflow is actively directed upward over the body. The final rear end shape was tuned so as to obtain the maximum aerodynamic benefit from this airflow. In addition, a large front spoiler was adopted to suppress airflow toward the underbody as much as possible. This works to increase airflow toward the roof, thereby augmenting the pressure
Reducing the carbon footprint by meeting stringent emission regulations and improving the fuel efficiency has become an essential feature in 21st century product design cycle for automobiles. Aerodynamic drag affects the fuel efficiency of the vehicle considerably. Various drag reduction devices such as air dam, rim cover, spoiler and undercover etc. are added in order to reduce the drag. This paper aims at understanding the effect of ground clearance on the performance of various aerodynamic drag reduction devices like - air-dam, spoiler, wheel cover and their combinations for hatchback vehicle using Computational Fluid Dynamics (CFD). CFD has been extensively used for exploring the various design configurations and has helped in selecting the optimized aero-parts configuration based on aerodynamic performance at concept stage which has ultimately reduced the vehicle drag coefficient by 10%. CFD results have been compared with wind tunnel testing for base configurations which is
Electric cars are the future of urban mobility which have very less carbon foot print. Unlike the conventional cars which uses BIW (Body in White), some of the electric cars are made with a space frame architecture, which is light weight and suitable for low volume production. In this architecture, underbody consists of frames, battery pack, electronics housing and electric motor. Underbody drag increases due to air entrapment around these components. Aerodynamic study for baseline model using CFD simulations showed that there was a considerable air resistance due to underbody components. To reduce the underbody drag, different add-ons are used and their effect on drag is studied. A front spoiler (air dam) is used to deflect the incoming air towards sides of the car. A under hood cover for front components, trailing arm cover for trailing arm and rear bumper cover for rear components were used to reduce underbody drag. Finally it is observed that aerodynamic behavior of the car
When a window opens to provide the occupant with fresh air flow while driving, wind throb problems may develop along with it. This work focuses on an analytical approach to address the wind throb issue for passenger vehicles when a front window or sunroof is open. The first case of this paper pertains to the front window throb issue for the current Ford Escape. Early in a program stage, CAA (Computational Aeroacoustics) analysis predicted that the wind throb level exceeded the program wind throb target. When a prototype vehicle became available, the wind tunnel test confirmed the much earlier analytical result. In an attempt to resolve this issue, the efforts focused on a design proposal to implement a wind spoiler on the side mirror sail, with the spoiler dimension only 6 millimeters in height. This work showed that the full vehicle CAA analysis could capture the impact of this tiny geometry variation on the wind throb level inside the vehicle cabin. The independent wind tunnel effort
This paper aims to provide a brief description on the aerodynamics development process of the new Nissan Qashqai using full-scale wind tunnel testing and Computational Fluid Dynamics simulations (CFD). Aerodynamic drag reduction ideas were developed by means of numerical simulations with confirmation of the aerodynamics properties full-scale clay models were tested in the wind tunnel. Key aerodynamic features were developed including the optimization of hood and windscreen angle, roof camber, plan view corner radius, rear combination lamp with boundary layer trip edge and a large rear spoiler with incorporated winglet. The drag contribution of the under body was reduced by optimizing deflectors and panels. The A-pillar and door mirrors were designed to reduce drag and wind noise. Furthermore, the bumper opening area was optimized to balance the airflow for engine cooling and a low cooling drag contribution. In addition, an active grille shutter was developed to limit the amount of
An air-dam spoiler is commonly used to reduce aerodynamic drag in production vehicles. However, it inexplicably tends to show different performances between wind tunnel and coast-down tests. Neither the reason nor the mechanism has been clarified. We previously reported that an air-dam spoiler contributed to a change in the wake structure behind a vehicle. In this study, to clarify the mechanism, we investigated the coefficient of aerodynamic drag CD reduction effect, wake structure, and underflow under different boundary layer conditions by conducting wind tunnel tests with a rolling road system and constant speed on-road tests. We found that the air-dam spoiler changed the wake structure by deceleration of the underflow under stationary floor conditions. Accordingly, the base pressure was recovered by approximately 30% and, the CD value reduction effect was approximately 10%. The ratio of the base pressure recovery to the CD value reduction effect was approximately 90%, suggesting
Nowadays, outer surface design of passenger cars is not just a matter of styling and safety but air flow around car body and exterior accessories has significant effect on fuel consumption, performance and dominantly on the wind noise. In recent years, passenger comfort is one of the most challenging and important automotive attributes for car makers. Controlling the turbulence eddies that causes aerodynamic noise can remarkably affect passenger's comfort quality. Identification of aerodynamic sources is considered as the first step in order to control the wind noise. In this research, computational fluid dynamics method is applied to simulate the wind flow around the car and the investigation of aerodynamic noise pattern is performed by numerical method which is the most prevalent way that is used by auto industries. By the advent of virtual simulations and by implementing these methods for the purpose of predicting and modifying in the whole car design phase, a considerable reduction
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