Internal Pressure Characteristics when Evaluating Dynamic Door Blow Out Deflection

Wind noise is one of the most influential NVH attributes that impact customer sensation of vehicle interior quietness. Among many factors that influence wind noise performance, the amount of dynamic door deflection under the pressure load due to fast movement of a vehicle plays a key roll. Excessive deflection could potentially lead to loss of sealing contact, causing aspiration leakage, which creates an effectual path through which the exterior aerodynamically induced noise propagates into the vehicle cabin. The dynamic door deflection can be predicted using CFD and CAE approaches which, in addition to modeling the structure correctly, require a correct pressure loading composed of external and internal pressure distributions. The determination of external pressure distributions can be fulfilled fairly straightforward by using commercial CFD codes such as Fluent, Star CCM+, Powerflow and others. However, the capability of predicting the internal pressure due to high wind speed outside of a vehicle has not been developed. This work looks into the internal pressure characteristics associated with the dynamic loading setup that is required for analytical efforts. The work is based on the wind tunnel measurement data involving several vehicles. By comparing the measured internal pressure data, along with CAE results, the issues are summarized and a conservative internal pressure load value is recommended.