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An experimental study for the characterization of ventilation fansas sources of structure-borne sound has been carried out.A source descriptoris proposed which is proportional to power and involves both the free veloci-ty and the source mobility at the contact point.The measurement methodsfor the free velocity and the source mobility for three degrees of freedom arepresented and the estimation of the source descriptor is demonstrated.A com-parison of force excitation source descriptors and moment excitation sourcedescriptors has been made and the results indicate that both force descriptorand moment descriptor decrease with increased frequency but themoment descriptor decreases more slowly.Moment induced emission maypredominate at high frequencies.
An experimental study for the characterization of ventilation fansas sources of structure-borne sound has been carried out. A source descriptoris proposed which is proportional to power and steering both the free veloci-ty and the source mobility at the contact point. Measurement methods for the free velocity and the source mobility for three degrees of freedom are presented and the estimation of the source descriptor is demonstrated. A com-parison of force excitation source descriptors and moment excitation source descriptors has been made and the results of that both indicate the moment of descriptornd moment descriptor decrease with increased frequency but themoment descriptor decreases more slowly. Motorized emission maypredominate at high frequencies.