Passive Flow Velocity and Direction Measurement System Under Interference Environment Based on the Turbulent Boundary Layer Pressure Fluctuation Field

To realize flow field monitoring without interference to the flow field, this study proposes a new passive flow velocity and flow direction measurement system. This method utilizes piezoelectric lead zirconium titanate (PZT) sensor arrays to measure the flow velocity and direction based on the relevant physical properties of the pressure fluctuation field of the turbulent boundary layer (TBL). Moreover, it can be widely used in flow field monitoring in limited and complex areas with strong interferences. First, the intensity and spatiotemporal characteristics of the TBL pressure fluctuation field are discussed, and the physical principles of three flow velocity measurement methods and two flow direction measurement methods are given according to the different physical characteristics. Second, the effectiveness of each method is verified using numerical simulations. Then, two basic array configurations are given, sensors are produced, and the flow velocity and flow direction measurements under interference environment are conducted in a water tunnel to verify the effectiveness of each measurement method and the noise reduction strategy. The advantages and disadvantages of each measurement method are discussed. Furthermore, neural networks are introduced to reduce the need for manual calibration. Finally, to improve the measurement accuracy and precision, a fusion strategy of the three flow velocity measurement methods is presented. The results prove that the flow velocity and flow direction measurement system can realize effective measurement without interfering with the flow field movement under interference environment.