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Brief Description
The field-scale experimental facility at Beacon Hill, Kowloon, HK, comprises a 250 m long pipeline network of 150 mm diameter (NS180) HDPE pipe. An upstream pressure-reducing valve (PRV) regulates incoming system pressure from 0.5 to 6 bar. The system has 8 access points allowing deployment of intrusive instruments (e.g., high frequency hydrophones and/or miniature robots). Valved cross-connections permit single, branched, or looped network topologies. The system has 12 bends ranging from 60 to 180 degrees, and the maximum allowable flow is at Reynolds number of 1.5×10^(5) and Mach number of 2.5×10^(-3). The facility is adaptable to provide a controlled testing environment to validate time-reversal theories.
Fig. 1: Schematic of the pipe system and example of high frequency (HF) access point for HF-TR experiments.
Technical specifications and measurement capabilities:
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The water supply is fed from the Beacon Hill reservoir at around 61 m of head;
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The flow is monitored by an electromagnetic flow meter, and the upstream pressure can be set with a pressure reducing valve (PRV). A ball valve designed for rapid closure is installed at the downstream end of the system.
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Acceleration and displacement sensors can be easily mounted. Triaxial piezoelectric accelerometers with high sensitivities of 10 mV/g (IPC 352A60 PCB accelerometer) and 316 pC/ms–2 (B&K 4326-A, charge accelerometer) with frequency ranging up to 60 kHz can be used. Displacements are captured with electrical resistive strain gauges.
