Browse Publications Technical Papers 2011-01-0153

Simulation and Analysis of Effects of Dynamic Pitching for Idealized Sedan-Type Vehicle Models 2011-01-0153

We investigate the pitching stability characteristics of sedan-type vehicles using large-eddy simulation (LES) technique. Pitching oscillation is a commonly encountered phenomenon when a vehicle is running on a road. Attributed to the change in a vehicle's position during pitching, the flow field around it is altered accordingly. This causes a change in aerodynamic forces and moments exerted on the vehicle. The resulting vehicle's response is complex and assumed to be unsteady, which is too complicated to be interpreted in a conventional wind tunnel or using a numerical method that relies on the steady state solution. Hence, we developed an LES method for solving unsteady aerodynamic forces and moments acting on a vehicle during pitching. The pitching motion of a vehicle during LES was produced by using the arbitrary Lagrangian-Eulerian technique. We compared two simplified vehicle models representing actual sedan-type vehicles with different pitching stability characteristics. The first phase of the simulations validated the numerical method adopted by comparing the flow structures, which was reproduced when a model was stationary, with wind tunnel visualizations. Then, a sinusoidal-forced-pitching oscillation was imposed on the models to probe their responses during pitching. The resulting aerodynamic pitching moment exerted on the models was phase averaged and decomposed into static, quasi-static, and dynamic components for evaluating their aerodynamic damping coefficients. This method successfully quantified the aerodynamic damping factors for vehicles subjected to pitching oscillation.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:

Unsteady Vehicle Aerodynamics during a Dynamic Steering Action: 1st Report, On-Road Analysis


View Details


Study on Influence of Mesh Parameters on Vehicle Aerodynamic Drag Coefficient


View Details


Aerodynamic Study of Prototype Motorcycle Using Experimental Techniques and Visualization Flow


View Details