The main purpose of this study is to study the aerodynamic mechanism of periodic roll motion of car body and provide engineering reference for car design and safety evaluation. A simplified roll motion model is established based on a real car model. The two-wheel centerline of the left-wheel symmetrical section is considered as the roll axis, and the overset mesh method was used to model the sinusoidal roll motion of the car. According to the experimental data, the frequency and maximum roll angle were set to be 10 Hz and 2.2°, respectively. A transient numerical solver based on the detached-eddy simulation method is employed. The accuracy of the numerical method is validated by means of the wind tunnel test. Due to the asymmetry of the movement, the aerodynamic change of the roll motion was obvious. It is found that the roll motion is closely related to the aerodynamic characteristics of the car. Because of the hysteresis effect, the phase of aerodynamic force on the car shifts and the most dangerous position of the car is obtained. In addition, the aerodynamic differences of the car parts are found, and the wake is analyzed in detail.
MassaguerEMassaguerAPujolT, et al. Fuel economy analysis under a WLTP cycle on a mid-size vehicle equipped with a thermoelectric energy recovery system. Energy2019; 179: 306–314.
2.
WangBXuY-LZhuLD, et al. Crosswind effect studies on road vehicle passing by bridge tower using computational fluid dynamics. Eng Appl Comput Fluid Mech2014; 8(3): 330–344.
3.
JalaliMHashemiEKhajepourA, et al. Model predictive control of vehicle roll-over with experimental verification. Control Eng Pract2018; 77: 95–108.
4.
Lorite-DíezMJiménez-GonzálezJIPasturL, et al. Drag reduction on a three-dimensional blunt body with different rear cavities under cross-wind conditions. J Wind Eng Ind Aerodynamics2020; 200: 104145.
5.
YinYRakhejaSBoileauPE.A roll stability performance measure for off-road vehicles. J Terramechanics2016; 64: 58–68.
6.
ChengSYTsubokuraMOkadaY, et al. Aerodynamic stability of road vehicles in dynamic pitching motion. J Wind Eng Ind Aerodynamics2013; 122: 146–156.
7.
Sadettin HamutHEl-EmamRSAydinM, et al. Effects of rear spoilers on ground vehicle aerodynamic drag. Int J Numer Methods Heat Fluid Flow2014; 24(3): 627–642.
8.
LiSGuZHuangT, et al. Coupled analysis of vehicle stability in crosswind on low adhesion road. Int J Numer Methods Heat Fluid Flow2018; 28: 1956–1972.
9.
KimSJKimHK.Feasibility of a quasi-static approach in assessing side-wind hazards for running vehicles. Appl Sci2019; 9(16): 3377.
10.
LjungskogESebbenSBroniewiczA.Inclusion of the physical wind tunnel in vehicle CFD simulations for improved prediction quality. J Wind Eng Ind Aerodynamics2020; 197: 104055.
11.
ColinORitterMLacourC, et al. DNS and LES of spark ignition with an automotive coil. Proc Combust Inst2018; 8: 21.
12.
HuangTLiSWanZ, et al. Investigation of vehicle stability under crosswind conditions based on coupling methods. Proc IMechE, Part D: J Automobile Engineering2019; 233(13): 3305–3317.
13.
AshtonNWestALardeauS, et al. Assessment of RANS and DES methods for realistic automotive models. Computers & Fluids2016; 128: 1–15.
14.
QuéméréPSagautP.Zonal multi-domain RANS/LES simulations of turbulent flows. Int J Numer Methods Fluids2002; 40(7): 903–925.
15.
WangBXuYLZhuLD, et al. Determination of aerodynamic forces on stationary/moving vehicle-bridge deck system under crosswinds using computational fluid dynamics. Eng Appl Comput Fluid Mech2013; 7(3): 355–368.
16.
HeCLiuYYavuzkurtS.A dynamic delayed detached-eddy simulation model for turbulent flows. Comput Fluids2017; 146: 174–189.
17.
RahmanMMVuorinenVTaghiniaJ, et al. Wall-distance-free formulation for SST k-ω model. Eur J Mech - B Fluids2019; 75(2019): 71–82.
18.
IgaliDMukhmetovOZhaoY, et al. Comparative analysis of turbulence models for automotive aerodynamic simulation and design. Int J Autom Technol2019; 20(6): 1145–1152.
DuarteCARDuarteLERde LimaBS, et al. Performance of an optimized k-ε turbulence model for flows around bluff bodies. Mech Res Commun2020; 105: 103518.
21.
RusdinA.Computation of turbulent flow around a square block with standard and modified k-ε turbulence models. Int J Autom Mech Eng2017; 14: 3938–3953.
22.
BuljacADžijanIKoradeI, et al. Automobile aerodynamics influenced by airfoil-shaped rear wing. Int J Autom Technol2016; 17(3): 377–385.
23.
DengEYangWDengL, et al. Time-resolved aerodynamic loads on high-speed trains during running on a tunnel–bridge–tunnel infrastructure under crosswind. Eng Appl Comput Fluid Mech2020; 14(1): 202–221.
24.
OkadaYNouzawaTNakamuraT, et al. Flow structures above the trunk deck of sedan-type vehicles and their influence on high-speed vehicle stability 1st report: on-road and wind-tunnel studies on unsteady flow characteristics that stabilize vehicle behavior. SAE Int J Passenger Cars Mech Syst2009; 2(1): 138–156.
25.
ChengSYTsubokuraMNakashimaT, et al. Numerical quantification of aerodynamic damping on pitching of vehicle-inspired bluff body. J Fluid Struct2012; 30(4): 188–204.
26.
WuBLiSCaoS, et al. Numerical investigation of the separated and reattaching flow over a 5:1 rectangular cylinder in streamwise sinusoidal flow. J Wind Eng Ind Aerodynamics2020; 198: 104120.
27.
CihanB.Numerical drag reduction of a Ground Vehicle by NACA2415 airfoil structured vortex generator and spoiler. Int J Autom Technol2019; 20(5): 943–948.
28.
ChangYYangZLiQ.Numerical and experimental research on flow and aerodynamic noise characteristics of coach. Proc IMechE, Part D: J Automobile Engineering2021; 235(6): 1685–1701.
