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The problem of squealing from vehicle windows opened or closed in partly wet conditions has been investigated. Experiments were conducted using a glass-run seal sample and a tangentially moving glass piece installed on a test bench. The instantaneous velocity of the glass was measured along with the total dynamic frictional force for varying normal static loads and sprayed-water distributions. The characteristics of squeal vibrations and the influence of normal load and water distribution are discussed. The relation between friction force and speed was also investigated. An idealized model consisting of a one-dimensional continuous rod excited by a moving frictional point force was then investigated. The method of averaging was applied to solve the nonlinear equations of motion. The response became unstable when the magnitude of the negative slope and the normal force were large regardless of boundary conditions.

Sunroof buffeting of a simplified car model was investigated experimentally and numerically in order to assess the potential of numerical methods to design sunroofs that are quiet and functional. The numerical results have been obtained using the commercially available software PowerFLOW. The simulation kernel of this software is based on the numerical scheme known as the Lattice Boltzmann Method (LBM), combined with an RNG turbulence model. This scheme accurately captures time-dependent aerodynamic behavior of high Reynolds number flows over complex geometries, together with the acoustic response of resonant systems. In this work, a simplified car model with a sunroof was used for validation. A simulation methodology to determine the acoustic response of the passenger cabin was investigated and verified experimentally. The sunroof buffeting phenomenon was simulated over a range of flow conditions, and the results were found to be in good agreement with experimental data.