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Article
Publication date: 12 September 2018

Shuya Li, Zhengqi Gu, Taiming Huang, Zhen Chen and Jun Liu

The purpose of this paper is to develop a two-way coupling approach for investigating the aerodynamic stability of vehicles under the combined effect of crosswind and road…

Abstract

Purpose

The purpose of this paper is to develop a two-way coupling approach for investigating the aerodynamic stability of vehicles under the combined effect of crosswind and road adhesion.

Design/methodology/approach

The author develops a new two-way coupling approach, which couples large eddy simulation with multi-body dynamics (MBD), to investigate the crosswind stability on three different adhesion roads: ideal road, dry road and wet road. The comparison of the results obtained using the traditional one-way coupling approach and the new two-way coupling approach is also done to assess the necessity to use the proposed coupling technique on low adhesion roads, and the combined effect of crosswind and road adhesion on vehicle stability is analyzed.

Findings

The results suggest that the lower the road adhesion is, the larger deviation a vehicle generates, the more necessary to conduct the two-way coupling simulation. The combined effect of the crosswind and road adhesion can decrease a vehicle’s lateral motion on a high adhesion road after the disappearing of the crosswind. But on a low adhesion road, the vehicle tends to be unstable for its large head wind angle. The vehicle stability in crosswind on a low adhesion road needs more attention, and the investigation should consider the coupling of aerodynamics and vehicle dynamics and the combined effect of crosswind and road adhesion.

Originality/value

Developing a new two-way coupling approach which can capture the complex vehicle structures and the road adhesion with MBD model and the completed fluid filed structure with CFD model. The present study might be the first study considering the coupling of crosswind and low adhesion road. The proposed two-way coupling approach will be useful for researchers who study vehicle crosswind stability.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 28 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 8 May 2018

Michal Kulak, Maciej Karczewski, Pawel Lesniewicz, Krzysztof Olasek, Bas Hoogterp, Guillaume Spolaore and Krzysztof Józwik

This paper aims to provide the results of investigations concerning an influence of the tyre with longitudinal grooves on the car body aerodynamics. It is considered as an…

Abstract

Purpose

This paper aims to provide the results of investigations concerning an influence of the tyre with longitudinal grooves on the car body aerodynamics. It is considered as an important aspect affecting the vehicle aerodynamic drag.

Design/methodology/approach

To investigate a contribution of grooved tyres to the overall vehicle drag, three wind tunnel experimental campaigns were performed (two by Peugeot Société Anonyme Peugeot Citroen, one at the Lodz University of Technology). In parallel, computational fluid dynamics (CFD) simulations were conducted with the ANSYS CFX software to enable formulation of wider conclusions.

Findings

The research shows that optimised tread patterns can be derived on a single tyre via a CFD study in combination with a controlled experiment to deliver designs actively lowering the overall vehicle aerodynamic drag.

Practical implications

A reduction in the aerodynamic drag is one of ways to decrease vehicle fuel consumption. Alternatively, it can be translated into an increase in the maximum travel velocity and the maximum distance driven (key factor in electric vehicles), as well as in a reduction of CO2 emissions. Finally, it can improve the vehicle driving and steering stability.

Originality/value

The tyre tread pattern analysis on isolated wheels provides an opportunity to cut costs of R&D and could be a step towards isolating aerodynamic properties of tyres, irrespective of the car body on which they are applied.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 28 no. 5
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 13 June 2020

Somashekar V. and Immanuel Selwyn Raj A.

This paper aims to deal with the numerical investigation of laminar separation bubble (LSB) characteristics (length and height of the bubble) of SS007 airfoil at the chord…

Abstract

Purpose

This paper aims to deal with the numerical investigation of laminar separation bubble (LSB) characteristics (length and height of the bubble) of SS007 airfoil at the chord Reynolds number of Rec = 0.68 × 105 to 10.28 × 105.

Design/methodology/approach

The numerical simulations of the flow around SS007 airfoil were carried out by using the commercial fluid dynamics (CFD) software, ANalysis system (ANSYS) 15. To solve the governing equations of the flow, a cell-centred control volume space discretisation approach is used. Wind tunnel experiments were conducted at the chord-based Reynolds number of Rec = 1.6 × 105 to validate the aerodynamic characteristics over SS007 airfoil.

Findings

The numerical results revealed that the LSB characteristics of a SS007 airfoil, and the aerodynamic performances are validated with experimental results. The lift and drag coefficients for both numerical and experimental results show very good correlation at Reynolds number 1.6 × 105. The lift coefficient linearly increases with the increasing angle of attack (AOA) is relatively small. The corresponding drag coefficient was found to be very small. After the formation of LSB which leads to burst to cause airfoil stall, the lift coefficient decreases and increases the drag coefficient.

Practical implications

Low Reynolds number and LSB characteristics concept in aerodynamics is predominant for both civilian and military applications. These include high altitude devices, wind turbines, human powered vehicles, remotely piloted vehicles, sailplanes, unmanned aerial vehicle and micro aerial vehicle. In this paper, the micro aerial vehicle flight conditions considered and investigated the LSB characteristics for different Reynolds number. To have better aerodynamic performances, it is strongly recommended to micro aerial vehicle (MAV) design engineers that the MAV is to fly at 12 m/s (cruise speed).

Social implications

MAVs and unmanned aerial vehicles seem to give some of the technical challenges of nature conservation monitoring and law enforcement a versatile, reliable and inexpensive solution.

Originality/value

The SS007 airfoil delays the flow separation and improves the aerodynamic efficiency by increasing the lift and decreasing the drag. The maximum increase in aerodynamic efficiency is 12.5% at stall angle of attack compared to the reference airfoil at Re = 2 × 105. The results are encouraging and this airfoil could have better aerodynamic performance for the development of MAV.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 8
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 7 June 2019

Zhen Chen, Zhengqi Gu and Zhonggang Wang

This paper aims to propose a precise turbulence model for vehicle aerodynamics, especially for vehicle window buffeting noise.

Abstract

Purpose

This paper aims to propose a precise turbulence model for vehicle aerodynamics, especially for vehicle window buffeting noise.

Design/methodology/approach

Aiming at the fact that commonly used turbulence models cannot precisely predict laminar-turbulent transition, a transition-code-based improvement is introduced. This improvement includes the introduction of total stress limitation (TSL) and separation-sensitive model. They are integrated into low Reynolds number (LRN) k-ε model to concern transport properties of total stress and precisely capture boundary layer separations. As a result, the ability of LRN k-ε model to predict the transition is improved. Combined with the constructing scheme of constrained large-eddy simulation (CLES) model, a modified LRN CLES model is achieved. Several typical flows and relevant experimental results are introduced to validate this model. Finally, the modified LRN CLES model is used to acquire detailed flow structures and noise signature of a simplified vehicle window. Then, experimental validations are conducted.

Findings

Current results indicate that the modified LRN CLES model is capable of achieving acceptable accuracy in prediction of various types of transition at various Reynolds numbers. And, the ability of this model to simulate the vehicle window buffeting noise is greater than commonly used models.

Originality/value

Based on the TSL idea and separation-sensitive model, a modified LRN CLES model concerning the laminar-turbulent transition for the vehicle window buffeting noise is first proposed.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 9
Type: Research Article
ISSN: 0961-5539

Keywords

Abstract

Details

Urban Transport and the Environment
Type: Book
ISBN: 978-0-08-047029-0

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Article
Publication date: 2 November 2015

Tien Phuc Dang, Zhengqi Gu and Zhen Chen

The purpose of this paper is to gain a better understanding of the flow field structure around the race car in two cases: stationary wheel and rotating wheel. In addition…

Abstract

Purpose

The purpose of this paper is to gain a better understanding of the flow field structure around the race car in two cases: stationary wheel and rotating wheel. In addition, this paper also illustrates and clarifies the influence of wheel rotation on the aerodynamic characteristics around the race car.

Design/methodology/approach

The author uses steady Reynolds-Averaged Navier-Stokes (RANS) equations with the Realizable k-ε model to study model open-wheel race car. Two cases are considered, a rotating wheel and stationary wheel.

Findings

The results obtained from the study are presented graphically, pressure, velocity distribution, the flow field structure, lift coefficient (Cl) and drag coefficient (Cd) for two cases and the significant influence of rotating case on flow field structure around wheel and aerodynamic characteristics of race car. The decreases in Cd and Cl values in the rotating case for the race car are 16.83 and 13.25 per cent, respectively, when compared to the stationary case.

Originality/value

Understanding the flow field structures and aerodynamic characteristics around the race car in two cases by the steady RANS equations with the Realizable k-ε turbulence model.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 25 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 18 May 2020

Yuan Ma, Mohammad Mehdi Rashidi, Rasul Mohebbi and Zhigang Yang

The nanofluid natural convection heat transfer in a hollow complex enclosure, which is named as Shamse knot shape, is studied numerically. This paper aims to present how…

Abstract

Purpose

The nanofluid natural convection heat transfer in a hollow complex enclosure, which is named as Shamse knot shape, is studied numerically. This paper aims to present how the Rayleigh number, nanoparticle volume fraction, Hartmann number and hollow side length affect the fluid flow and heat transfer characteristics.

Design/methodology/approach

The continuity, momentum and energy equations have been solved using lattice Boltzmann method (LBM). Numerical simulation has been obtained for a wide range of Rayleigh number (103 ≤ Ra ≤ 106), nanoparticle volume fraction (0 ≤ ϕ 0.05) and Hartmann number (0 ≤ Ha ≤ 60) to analyze the fluid flow pattern and heat transfer characteristics. Moreover, the effect of hollow side length (D) on flow field and thermal performance is studied.

Findings

The results showed that the magnetic field has a negative effect on the thermal performance and the average Nusselt number decreases by increasing the Hartmann number. Because of the high conduction heat transfer coefficient of nanoparticles, the average Nusselt number increases by rising the nanoparticle volume fraction. The effect of adding nanoparticles on heat transfer is more effective at low nanoparticle volume fraction (0 ≤ ϕ ≤ 0.01). It was also found that at Ra = 106, when the hollow side length increases to 3, the flow pattern becomes different due to the small gap. The averaged Nu is an increasing function of D at low Ra and an opposite trend occurs at high Rayleigh number.

Originality/value

For the first time, the effects of magnetic field, Rayleigh number, nanoparticle volume fraction and hollow side length on natural convection heat transfer of hybrid nanofluid (Ag-TiO2/water) is investigated in a complicated cavity.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 10 July 2019

Zhen Chen, Zhenqqi Gu and Tao Jiang

The main purpose of this paper is to gain a better understanding of the transient aerodynamic characteristics of moving windshield wipers. In addition, this paper also…

Abstract

Purpose

The main purpose of this paper is to gain a better understanding of the transient aerodynamic characteristics of moving windshield wipers. In addition, this paper also strives to illustrate and clarify how the wiper motion impacts the airflow structure; the aerodynamic interaction of two wipers is also discussed.

Design/methodology/approach

A standard vehicle model proposed by the Motor Industry Research Association and a pair of simplified bone wipers are introduced, and a dynamic mesh technique and user-defined functions are used to achieve the wiper motion. Finite volume methods and large eddy simulation (LES) are used to simulate the transient airflow field. The simulation results are validated through the wind tunnel test.

Findings

The results obtained from the study are presented graphically, and pressure, velocity distributions, airflow structures, aerodynamic drag and lift force are shown. Significant influences of wiper motion on airflow structures are achieved. The maximum value of aerodynamic lift and drag force exists when wipers are rotating and there is a certain change rule. The aerodynamic lift and drag force when wipers are rotating downward is greater than when wipers are rotating upward, and the force when rotating upward is greater than that when steady. The aerodynamic lift and drag forces of the driver-side wiper is greater than those of the passenger-side wiper.

Originality/value

The LES method in combination with dynamic mesh technique to study the transient aerodynamic characteristics of windshield wipers is relatively new.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 17 August 2020

Ali Belhocine and Oday Ibraheem Abdullah

This study aims to investigate numerically a thermomechanical behavior of disc brake using ANSYS 11.0 which applies the finite element method (FEM) to solve the transient…

Abstract

Purpose

This study aims to investigate numerically a thermomechanical behavior of disc brake using ANSYS 11.0 which applies the finite element method (FEM) to solve the transient thermal analysis and the static structural sequentially with the coupled method. Computational fluid dynamics analysis will help the authors in the calculation of the values of the heat transfer (h) that will be exploited in the transient evolution of the brake disc temperatures. Finally, the model resolution allows the authors to visualize other important results of this research such as the deformations and the Von Mises stress on the disc, as well as the contact pressure of the brake pads.

Design/methodology/approach

A transient finite element analysis (FEA) model was developed to calculate the temperature distribution of the brake rotor with respect to time. A steady-state CFD model was created to obtain convective heat transfer coefficients (HTC) that were used in the FE model. Because HTCs are dependent on temperature, it was necessary to couple the CFD and FEA solutions. A comparison was made between the temperature of full and ventilated brake disc showing the importance of cooling mode in the design of automobile discs.

Findings

These results are quite in good agreement with those found in reality in the brake discs in service and those that may be encountered before in literature research investigations of which these will be very useful for engineers and in the design field in the vehicle brake system industry. These are then compared to experimental results obtained from literatures that measured ventilated discs surface temperatures to validate the accuracy of the results from this simulation model.

Originality/value

The novelty of the work is the application of the FEM to solve the thermomechanical problem in which the results of this analysis are in accordance with the realized and in the current life of the braking phenomenon and in the brake discs in service thus with the thermal gradients and the phenomena of damage observed on used discs brake.

Details

World Journal of Engineering, vol. 17 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

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Article
Publication date: 23 March 2010

D.W. Marshall, S.J. Newman and C.B. Williams

The purpose of this paper is to investigate the effect a variety of different boundary layers have on a wing in ground‐effect.

Abstract

Purpose

The purpose of this paper is to investigate the effect a variety of different boundary layers have on a wing in ground‐effect.

Design/methodology/approach

Experiments were carried out in the University of Southampton's 3′×2′ wind tunnel. A variable length splitter plate was designed and manufactured in order to generate four boundary‐layer thicknesses at a selected measurement position. A single element inverted GA(W)‐1 aerofoil was then introduced to the flow at varying heights above the plate. Laser Doppler anemometry (LDA) and surface static pressure measurements (both on the aerofoil surface and on the splitter plate) were recorded.

Findings

The flow beneath the wing is found to be affected considerably by the presence of the boundary layer. As the boundary‐layer thickness is increased, the under‐wing pressure is observed to increase, hence resulting in decreased suction. Further, the LDA results indicate a modification to the wake profile. In particular, at low wing heights, the wake is observed to become entrained in the boundary layer, to differing degrees dependant on the boundary layer present and the wing height.

Research limitations/implications

The acquisition of force values from the tests will have allowed further understanding of the “real world” implications of the presence of the boundary‐layer thicknesses on a wing in ground‐effect but this is not possible in the test facility used.

Practical implications

The aerodynamics of a wing in ground‐effect are of great interest for both lifting surfaces for aircraft and downforce generation in motorsport applications. The implications of this paper enhance the importance of understanding the boundary conditions present when wind tunnel testing for these applications.

Originality/value

Although the influence of the boundary layer on low ground clearance objects has been well documented, the methods used here, in particular the use of the pressure tapped splitter plate and LDA, allow a further insight into the explanations behind this influence.

Details

Aircraft Engineering and Aerospace Technology, vol. 82 no. 2
Type: Research Article
ISSN: 0002-2667

Keywords

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