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Aerodynamics and Aeroacoustics of Vehicles

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Published Papers

A special issue of Fluids (ISSN 2311-5521). This special issue belongs to the section "Turbulence".

Deadline for manuscript submissions: closed (1 December 2020) | Viewed by 65367

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Special Issue Editor

Prof. Dr. Mesbah Uddin

E-Mail Website
Guest Editor

1. Professor, Department of Mechanical Engineering & Engineering Science, The University of North Carolina at Charlotte, Charlotte, NC 28228-0001, USA
2. Coordinator, Digital Design Optimization Initiative, The University of North Carolina at Charlotte, Charlotte, NC 28228-0001, USA
3. Chair, SAE Road Vehicles Aerodynamics Committee, Warrendale, PA, USA
Interests: race and street car aerodynamics; aerodynamics and aeroacoustics of passenger and commercial vehicles; experimental and computational study of jets, wakes, and boundary layer flows; flow separation and control; aerodynamics of small aerial vehicles; shock–boundary layer interactions; data-driven turbulence modeling; machine learning methods in fluid flow classification
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Special Issue Information

Dear Colleagues,

Aerodynamics is one of the major factors to consider during the design and development phases of vehicles, be they passenger or commercial road vehicles, race cars, trains, or air vehicles. During the early days of vehicle aerodynamics, improved fuel economy and speed gain by drag reduction, and improving occupant safety and comfort by minimizing the effects of aerodynamic instability were the major goals of vehicle aerodynamics. However, as ground vehicles became faster and high-speed road and train transportation infrastructures were developed, aerodynamic flow instability induced wind noise or aeroacoustics became another significant design consideration, aeroacoustics became an integral part of vehicle aerodynamic design. Though drag reduction and wind noise control are the primary considerations for passenger and commercial vehicles, race cars and high-performance road and street cars require the creation of an aerodynamic downforce for better traction and cornering. Thus, aerodynamics has become the single most important aspect of race and performance vehicle designs. In addition, it is recently observed that significant drag reduction and, hence, improved fuel economy can be achieved when road vehicles are driven in convoy, called platooning; the same phenomenon is used in racing called drafting for increased speed.

Road and track testing, wind tunnel experiments, and computer simulations are the three tools of trade used in vehicle aerodynamics. All these three approaches have their advantages and limitations. Correlating results from these approaches for the same vehicle is challenging, and improving the correlations between these approaches is an ongoing process. As such, we see newer on-road and wind-tunnel measurement techniques and CFD methodologies evolving continuously. Additionally, efforts are ongoing to include the effects of real-life read road conditions, like the impact of wind gusts or crosswind on vehicle performance, stability, and control, in laboratory environments. Over the last few decades, considerable improvements are made in these areas, and this trend is continuing.

In consideration of the above, we have planned a Special Issue of the journal Fluids, dedicated to recent developments in experimental and modeling methodologies as applied to vehicle aerodynamics and aeroacoustics. The potential topics for submissions include but are not limited to the following broad areas:

Road, train, air and race vehicle aerodynamics;
Computational fluid dynamics (CFD) modelling and simulation of vehicle internal and external flows;
Wind tunnel testing of vehicles;
Road and track testing of ground vehicles;
Fundamentals of vehicle aerodynamics;
Drag reduction and flow control methodologies for vehicle flows;
Wind tunnel aeroacoustics measurements and testing techniques;
Modelling and simulations of ground vehicle aeroacoustics;
Wind noise reduction methodologies;
Road vehicle platooning and driving in proximity in racing;
Crosswind stability of ground vehicles;
Replication of on-road conditions in wind tunnel experiments;
CFD–wind tunnel correlation for aerodynamic and aeroacoustics measurements.

Prof. Dr. Mesbah Uddin
Guest Editor

Manuscript Submission Information

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Keywords

aerodynamics and aeroacoustics of passenger and commercial road vehicles
aerodynamics of trains and race vehicles
transient aerodynamics and aeroacoustics simulations of vehicle flows
experimental techniques applied in road and air vehicle aerodynamics
flow controls applied to road and air vehicles and trains
aerodynamic shape optimization of vehicles
road vehicle overtaking maneuvers and platooning
effect of rapid changes in upstream flow conditions on the vehicle aerodynamic characteristics
interactions of vehicle flow with surrounding infrastructure

Published Papers (11 papers)

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Research

17 pages, 10108 KiB

Open AccessArticle

Development of an Algebraic Model of Empirical Parameterization of Near Wakes around a Vehicle

by Arata Kimura, Mitsufumi Asami, Hideyuki Oka and Yasushi Oka

Fluids 2021, 6(2), 75; https://doi.org/10.3390/fluids6020075 - 8 Feb 2021

Cited by 1 | Viewed by 1908

Abstract

In this paper, we describe and evaluate an algebraic model that has been adopted in a diagnostic wind flow model. Our numerical model is based on the Röckle’s wind modelling approach and we intend to reproduce the steady-state flow patterns of recirculation vortices that are generated in the near-wake region behind a vehicle. The evaluation of the practicality of our proposed model is performed by comparing the wind tunnel experiments of the flow around a vehicle conducted by the Loughborough University. We also compare the numerical results of our model with the CFD model. The proposed model reproduces the flow patterns behind a vehicle and it has significant advantages, such as low numerical costs. We expect that further improvements in the algebraic model when considering the vehicle’s shape will improve its practicality for the numerical analysis of flow fields around a vehicle. Full article

(This article belongs to the Special Issue Aerodynamics and Aeroacoustics of Vehicles)

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20 pages, 6632 KiB

Open AccessArticle

An Investigation of Aerodynamic Effects of Body Morphing for Passenger Cars in Close-Proximity

by Geoffrey Le Good, Max Resnick, Peter Boardman and Brian Clough

Fluids 2021, 6(2), 64; https://doi.org/10.3390/fluids6020064 - 1 Feb 2021

Cited by 8 | Viewed by 2819

Abstract

The potential energy-saving benefit for vehicles when travelling in a ‘platoon’ formation results from the reduction in total aerodynamic drag which may result from the interaction of bluff bodies in close-proximity. Early investigations of platooning, prompted by problems of congestion, had shown the potential for drag reduction but was not pursued. More recently, technologies developed for connected-autonomous vehicle control have provided a renewed interest in platooning particularly within the commercial vehicle industry. To date, most aerodynamics-based considerations of platooning have been conducted to assess the sensitivity of drag-saving to vehicle spacing and were based on formations of identically shaped constituents. In this study, the interest was the sensitivity of drag-saving to the shape of the individual platoon constituents. A new reference car, the Resnick model, was specially designed to include front and rear-end add-on sections to make distinct changes in profile form and simulate large-scale body morphing. The results of wind tunnel tests on small-scale models suggested that current trends in low-drag styling may not provide the ideal shape for platoon constituent members and that optimised forms are likely to be dependent upon position in the platoon. Full article

(This article belongs to the Special Issue Aerodynamics and Aeroacoustics of Vehicles)

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16 pages, 3520 KiB

Open AccessArticle

Some Observations on Shape Factors Influencing Aerodynamic Lift on Passenger Cars

by Jeff Howell, Steve Windsor and Martin Passmore

Fluids 2021, 6(1), 44; https://doi.org/10.3390/fluids6010044 - 18 Jan 2021

Cited by 4 | Viewed by 8003

Abstract

The car aerodynamicist developing passenger cars is primarily interested in reducing aerodynamic drag. Considerably less attention is paid to the lift characteristics except in the case of high-performance cars. Lift, however, can have an effect on both performance and stability, even at moderate speeds. In this paper, the basic shape features which affect lift and the lift distribution, as determined from the axle loads, are examined from wind tunnel tests on various small-scale bodies representing passenger cars. In most cases, the effects of yaw are also considered. The front-end shape is found to have very little effect on overall lift, although it can influence the lift distribution. The shape of the rear end of the car, however, is shown to be highly influential on the lift. The add-on components and other features can have a significant effect on the lift characteristics of real passenger cars and are briefly discussed. The increase in lift at yaw is, surprisingly, almost independent of shape, as shown for the simple bodies. This characteristic is less pronounced on real passenger cars but lift increase at yaw is shown to rise with vehicle length. Full article

(This article belongs to the Special Issue Aerodynamics and Aeroacoustics of Vehicles)

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21 pages, 9064 KiB

Open AccessArticle

Three-Dimensional Simulation of New Car Profile

by Hamdy Mansour, Rola Afify and Omar Kassem

Fluids 2021, 6(1), 8; https://doi.org/10.3390/fluids6010008 - 29 Dec 2020

Cited by 3 | Viewed by 6210

Abstract

Aerodynamics has identified remarkable development in the improvement of fuel efficiency, reducing wind noise and increasing engine cooling. Moving body profile controls fuel the consumption rate. This paper discusses a novel car profile consisting of two airfoils Roncz (car profile) and National Advisory Committee for Aeronautics NACA 10 (car sides). They are used to create a streamlined body. Three-Dimensional numerical simulations of the full scale model (half domain) are performed to examine the effect of car profile on the drag coefficient and thus fuel consumption. Simulations are considered over a range of air flow velocities, from 20 to 45 km/h in a step of 5 km/h. The ahmed body is used to validate the results. Results are shown graphically for coefficients of drag and lift and pressure and velocity contours. They show that the design of the car profile is effective. Full article

(This article belongs to the Special Issue Aerodynamics and Aeroacoustics of Vehicles)

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Graphical abstract

24 pages, 36309 KiB

Open AccessArticle

The Effect of Cornering on the Aerodynamics of a Multi-Element Wing in Ground Effect

by Dipesh Patel, Andrew Garmory and Martin Passmore

Fluids 2021, 6(1), 3; https://doi.org/10.3390/fluids6010003 - 22 Dec 2020

Cited by 6 | Viewed by 5275

Abstract

This research investigates the effects of cornering on a multi-element wing in ground effect with the aim to improve the understanding of such in the effort to improve the performance of open-wheel race cars. A numerical validation study was performed to confirm the validity of the Detached Eddy Simulation CFD methodology used. This involved comparing numerical data with wind tunnel experimental data using a force balance and PIV for the velocity field to reveal the trajectory of the trailing vortex system. Once validated, the CFD was used to test the wing within a cornering condition as well as fixed yaw condition and its aerodynamic performance relative to the straight-line condition was analysed. Asymmetry was the general theme concerning the on-surface pressure distribution with this most prominent under the cornering condition. Ultimately, minimal change was observed regarding the downforce generated whilst drag was found to increase in the cornering condition and decrease slightly in the fixed yaw condition. Asymmetry was also observed in the wake of the wing where alterations to the relative strengths of the vortices was observed as well as their downstream paths which was generally governed by the direction of the freestream flow. Full article

(This article belongs to the Special Issue Aerodynamics and Aeroacoustics of Vehicles)

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26 pages, 6629 KiB

Open AccessArticle

Computational Aerodynamics Analysis of Non-Symmetric Multi-Element Wing in Ground Effect with Humpback Whale Flipper Tubercles

by Benjamin Arrondeau and Zeeshan A. Rana

Fluids 2020, 5(4), 247; https://doi.org/10.3390/fluids5040247 - 17 Dec 2020

Cited by 4 | Viewed by 4265

Abstract

The humpback whale flipper tubercles have been shown to improve the aerodynamic coefficients of a wing, especially in stall conditions, where the flow is almost fully detached. In this work, these tubercles were implemented on a F1 front-wing geometry, very close to a [...] Read more.

k - ω

SST turbulence model and the overall effects of the tubercles on the flow behavior were analyzed. The optimal amplitude and number of tubercles was determined in this study for this front wing where an improvement of

22.6 %

and

9.4 %

is achieved, respectively, on the lift and the

L / D

ratio. On the main element, the stall was delayed by

167.7 %

. On the flap, the flow is either fully detached, in the large circulation zone, or fully attached. Overall, in stall conditions, tubercles improve the downforce generation but at the cost of increased drag. Furthermore, as the tubercles are case-dependent, an optimal configuration for tubercles implementation also exists for any geometry. Full article

(This article belongs to the Special Issue Aerodynamics and Aeroacoustics of Vehicles)

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18 pages, 27258 KiB

Open AccessArticle

The Effect of Single Dielectric Barrier Discharge Actuators in Reducing Drag on an Ahmed Body

by Saber Karimi, Arash Zargar, Mahmoud Mani and Arman Hemmati

Fluids 2020, 5(4), 244; https://doi.org/10.3390/fluids5040244 - 15 Dec 2020

Cited by 3 | Viewed by 2779

Abstract

The feasibility of a single dielectric barrier discharge (SDBD) actuator in controlling flow over an Ahmed body, representing a simplified car model, has been numerically and experimentally investigated at Reynolds numbers of

7.68 \times 10^{5}

and

2.25 \times 10^{5}

. The [...] Read more.

7.68 \times 10^{5}

and

2.25 \times 10^{5}

. The Ahmed body had slant angles of

25^{\circ}

and

35^{\circ}

. The results showed that SDBD actuators could significantly enhance the aerodynamic performance of the Ahmed body. Several arrangements of the actuators on the slant surface and the rear face of the model were examined to identify the most effective arrangement for drag reduction. This arrangement resulted in an approximately

6.1 %

drag reduction. This improvement in aerodynamic performance is attributed to the alteration of three-dimensional wake structures due to the presence of SDBD, which coincides with surface pressure variations on the slant and rear faces of the Ahmed body. Full article

(This article belongs to the Special Issue Aerodynamics and Aeroacoustics of Vehicles)

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23 pages, 9614 KiB

Open AccessArticle

Aerodynamic and Structural Design of a 2022 Formula One Front Wing Assembly

by Xabier Castro and Zeeshan A. Rana

Fluids 2020, 5(4), 237; https://doi.org/10.3390/fluids5040237 - 9 Dec 2020

Cited by 9 | Viewed by 15987

Abstract

The aerodynamic loads generated in a wing are critical in its structural design. When multi-element wings with wingtip devices are selected, it is essential to identify and to quantify their structural behaviour to avoid undesirable deformations which degrade the aerodynamic performance. This research investigates these questions using numerical methods (Computational Fluid Dynamics and Finite Elements Analysis), employing exhaustive validation methods to ensure the accuracy of the results and to assess their uncertainty. Firstly, a thorough investigation of four baseline configurations is carried out, employing Reynolds Averaged Navier–Stokes equations and the k-ω SST (Shear Stress Transport) turbulence model to analyse and quantify the most important aerodynamic and structural parameters. Several structural configurations are analysed, including different materials (metal alloys and two designed fibre-reinforced composites). A 2022 front wing is designed based on a bidimensional three-element wing adapted to the 2022 FIA Formula One regulations and its structural components are selected based on a sensitivity analysis of the previous results. The outcome is a high-rigidity-weight wing which satisfies the technical regulations and lies under the maximum deformation established before the analysis. Additionally, the superposition principle is proven to be an excellent method to carry out high-performance structural designs. Full article

(This article belongs to the Special Issue Aerodynamics and Aeroacoustics of Vehicles)

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23 pages, 63617 KiB

Open AccessArticle

Experimental Data for the Validation of Numerical Methods: DrivAer Model

by Max Varney, Martin Passmore, Felix Wittmeier and Timo Kuthada

Fluids 2020, 5(4), 236; https://doi.org/10.3390/fluids5040236 - 8 Dec 2020

Cited by 10 | Viewed by 12369

Abstract

As the automotive industry strives to increase the amount of digital engineering in the product development process, cut costs and improve time to market, the need for high quality validation data has become a pressing requirement. While there is a substantial body of experimental work published in the literature, it is rarely accompanied by access to the data and a sufficient description of the test conditions for a high quality validation study. This paper addresses this by reporting on a comprehensive series of measurements for a 25% scale model of the DrivAer automotive test case. The paper reports on the measurement of the forces and moments, pressures and off body PIV measurements for three rear end body configurations, and summarises and compares the results. A detailed description of the test conditions and wind tunnel set up are included along with access to the full data set. Full article

(This article belongs to the Special Issue Aerodynamics and Aeroacoustics of Vehicles)

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13 pages, 8177 KiB

Open AccessArticle

Aerodynamic Investigation of a Morphing Wing for Micro Air Vehicle by Means of PIV

by Rafael Bardera, Ángel Rodríguez-Sevillano and Adelaida García-Magariño

Fluids 2020, 5(4), 191; https://doi.org/10.3390/fluids5040191 - 27 Oct 2020

Cited by 5 | Viewed by 2037

Abstract

A wind tunnel tests campaign has been conducted to investigate the aerodynamic flow around a wing morphing to be used in a micro air vehicle. Non-intrusive whole field measurements were obtained by using PIV, in order to compare the velocity and turbulence intensity maps for the modified and the original version of an adaptive wing designed to be used in a micro air vehicle. Four sections and six angles of attack have been tested. Due to the low aspect ratio of the wing and the low Reynold number tested of 6.4 × 10⁴, the influence of the 3D effects has been proved to be important. At high angles of attack, the modified model prevented the detachment of the stream, increased the lift of the wing and reduced the turbulence intensity level on the upper surface of the airfoil and in the wake. Full article

(This article belongs to the Special Issue Aerodynamics and Aeroacoustics of Vehicles)

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17 pages, 6355 KiB

Open AccessArticle

The Influence of Different Unsteady Incident Flow Environments on Drag Measurements in an Open Jet Wind Tunnel

by Xiao Fei, Christoph Jessing, Timo Kuthada, Jochen Wiedemann and Andreas Wagner

Fluids 2020, 5(4), 178; https://doi.org/10.3390/fluids5040178 - 13 Oct 2020

Cited by 3 | Viewed by 2189

Abstract

Aerodynamic development for road vehicles is usually carried out in a uniform steady-state flow environment, either in the wind tunnel or in Computational Fluid Dynamics (CFD) simulations. However, out on the road, the vehicle experiences unsteady flow with fluctuating angles of incidence

β

[...] Read more.

β

, caused by natural wind, roadside obstacles, or traffic. In order to simulate such flow fields, the Forschungsinstitut für Kraftfahrwesen und Fahrzeugmotoren Stuttgart (FKFS) swing^® system installed in the quarter scale model wind tunnel can create a variety of time-resolved signals with variable

β

. The static pressure gradient in the empty test section, as well as

c_{D}

values of the Society of Automotive Engineers (SAE) body and the DrivAer model, have been measured under these transient conditions. The

c_{D}

measurements have been corrected using the Two-Measurement Correction method in order to decouple the influence of the unsteady flow from that of the static pressure gradient. The investigation has determined that the static pressure gradient in the empty test section varies greatly with different excitation signals. Thus, it is imperative to apply a

c_{D}

correction for unsteady wind tunnel measurements. The corrected

c_{D}

values show that a higher signal amplitude, as in, signals with large

β

, lead to higher drag forces. The influence of the signal frequency on drag values varies depending on the vehicle geometry and needs to be investigated further in the future. Full article

(This article belongs to the Special Issue Aerodynamics and Aeroacoustics of Vehicles)

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