Study of pressure fluctuations generated by an expansion

摘要

In the flows of nuclear reactors pipelines, and those of many others industrial installations, we observe an excitation induced by the local fluctuate pressure field in the level of singularities and moreover by acoustic sources in connection with these singularities. Thus, these phenomena can induce vibratory excitations of the structures whose intensity is often unacceptable. Therefore, it is important to develop prevision methods of vibratory levels in order to understand the excitation processes and to minimise the risks associated with the behaviour of these mechanical structures. We have chosen to study in this paper the singularity constituted by an expansion (due to the fact that the flow passes from a tube of diameter d to one of diameter D where d