Bonnet Flutter Under Traffic Conditions
2022-01-1095
03/29/2022
- Event
- Content
- Traditionally, vehicle aerodynamics development has focussed on the use of idealized environment conditions. For example, vehicle aerodynamics is often assessed and optimized using steady, low-turbulence, zero yaw onset flows. This idealized flow condition, while useful, leaves the range of onset flow conditions experienced by the vehicle in the real world largely unexplored. On the road, disturbances caused by atmospheric turbulence and traffic can have a significant impact on vehicle performance. In this paper we explore the impact of unsteady wake flows on the vehicle bonnet system. This is based on our previous work, which demonstrated that a combination of a Lattice-Boltzmann based Very Large Eddy flow simulation tool and Finite Element analysis, providing a one-way coupled CFD to FEA simulation can predict structural vibration of a vehicle bonnet due to aerodynamic excitation (“bonnet flutter”). Here, we use a previously validated Transient Boundary Seeding (TBS) technique to capture the wake of a vehicle and use it as an upstream boundary condition for bonnet flutter simulations. This reduced-effort technique allows the efficient simulation of the interaction of a downstream vehicle with realistically disturbed onset flow over a range of longitudinal and lateral offsets. In turn, this identifies a worst-case scenario for real world driving conditions that can be used for subsequent structural optimization of bonnet systems.
- Citation
- Gaylard, A., Gargoloff, J., Arata, J., and Jilesen, J., "Bonnet Flutter Under Traffic Conditions," SAE Technical Paper 2022-01-1095, 2022, .