Numerical quantification of aerodynamic damping on pitching of vehicle-inspired bluff body

• Published in: Journal of fluids and structures Vol. 30; pp. 188 - 204
• Main Authors: Cheng, S.Y., Tsubokura, M., Nakashima, T., Okada, Y., Nouzawa, T.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.04.2012; Elsevier
• Subjects: Aerodynamic damping; Aerodynamics; Applied fluid mechanics; Computational methods in fluid dynamics; Damping; Dynamic response; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); LES; Marine; Mathematical models; Oscillation; Physics; Pitching; Pitching moments; Stability; Transient aerodynamics; Turbulence simulation and modeling; Turbulent flows, convection, and heat transfer; Underbodies; Vehicle; Vehicles; Vehicle; Pitching; Aerodynamic damping; Transient aerodynamics; LES; Oscillation; Vehicle stability; Transient response; Computational fluid dynamics; Bluff body; Transient flow; Aerodynamics; Car body; Automobiles; Vehicle dynamics; Vibrations; Large eddy simulation; Dimensional analysis; Modelling
• ISSN: 0889-9746; 1095-8622
• DOI: 10.1016/j.jfluidstructs.2012.01.002

The influence of transient flows on vehicle stability was investigated by large eddy simulation. To consider the dynamic response of a vehicle to real-life transient aerodynamics, a dimensionless parameter that quantifies the amount of aerodynamic damping for vehicle subjects to pitching oscillation is proposed. Two vehicle models with different stability characteristics were created to verify the parameter. For idealized notchback models, underbody has the highest contribution to the total aerodynamic damping, which was up to 69%. However, the difference between the aerodynamic damping of models with distinct A- and C-pillar configurations mainly depends on the trunk-deck contribution. Comparison between dynamically obtained phase-averaged pitching moment with quasi-steady values shows totally different aerodynamic behaviors. ► We introduce a coefficient to quantify the aerodynamic damping for road vehicle. ► Underbody has the highest contribution to the total aerodynamic damping. ► Difference in aerodynamic damping of vehicles depends on the trunk-deck contribution.