Determination of the linear frequency response of single pipelines using persistent transient excitation: a numerical investigation

The linear frequency response of a fluid-filled pipeline extracted by fluid transient waves can be used to detect leaks in pipelines. This research conducts numerical analysis on how to accurately determine the linear frequency response diagram (FRD) of single pipelines using persistent transient pressure signals. Two types of persistent signals, the maximum-length binary sequence and the inverse-repeat sequence (IRS), are compared in terms of the accuracy in estimating the linear response of a pipeline at resonant frequencies. The IRS is found to be more appropriate for identifying the linear portion of the FRD of a pipeline, since its antisymmetric property can supress part of the nonlinear response. Numerical simulations are conducted to verify the findings.