Abstract:
A mathematical model and computer program has been developed to predict the sound inside an automotive passenger compartment due to wind noise. Using steady-state information on pressure distributions along the glass surfaces, the program computes the impact of vortices on the vibrational characteristics of the glass and the radiated sound from it. It also accounts for the sound radiated through the door seals and combines them for a composite sound-pressure level (SPL) estimate at the driver's ear location. This SPL spectrum is computed at the 1/3-oct frequencies from 25 Hz to 10 kHz. The program also computes the overall SPL, loudness, and % speech intelligibility. Using optimization techniques, the model allows for a desired SPL spectrum to be specified along with a set of design variables. It then automatically computes the values needed by these variables to come as close as possible to the desired spectrum. The model has been validated over a wide range of cars and trucks. Typical accuracy is (plus or minus) 3 dB within the frequency range, (plus or minus) 1 dB for the overall SPL. Examples will be shown demonstrating this accuracy and illustrating how this system can help design quieter road vehicles.