Document Type : Research Paper
Faculty of Water and Environmental Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR.
Blockages in water supply systems can arise from diverse causes, leading to pollution, energy loss, and reduced system performance. Detecting and addressing these blockages is crucial for managing pressurized systems like water supply and pipe networks. Analyzing pressure signals is a common method for detecting defects, with transient pressure signals being particularly effective compared to steady-state signals. This study focuses on experimentally investigating the impact of extended blockages on pressure signal characteristics in viscoelastic pipelines within the time and frequency domains. Elastic blockages of varying lengths and diameters were used in a laboratory experimental model of a viscoelastic pipeline. The findings reveal that blockages cause changes in the pressure signal shape, resonance frequencies, and phase in different domains. These changes are more pronounced with longer and higher percentage blockages. Increasing blockage length amplifies phase shifts and wave reflections, with pressure increase delayed by damping. Higher blockage percentages induce phase shifts and amplitude reflections during transient flow. Transient flow intensity affects only amplitude, not phase, with more pronounced reflections at high intensity. Blockage location influences the distribution of phase and amplitude frequencies. Geometric changes induce phase shifts and alter amplitude frequencies, while hydraulic characteristics solely impact amplitude.