Testing and Performance Analysis of a New Wireless Sensors Network (WSN) System for Hurricane Monitoring
Researchers at the Florida Institute of Technology (FIT) have developed the wireless sensor network system for the field measurement of hurricane wind and pressure on residential structures. A new version of the system is developed using the latest state-of-the-art technologies which performance is tested during the passing of hurricane Isaias (2020) and the Wall of Wind (WOW) at Florida International University (FIU). The old version system sensors were applied during hurricane Dorian (2019). For the three events, 25 pressure sensors and one anemometer were placed on the roof of a single-story house. Hurricane Dorian data was collected for 72 hours in total from September 2, 2019, and Hurricane Isaias for 78 hours from August 1, 2020. The WOW tests were performed on September 3, 4, and 8, 2020. The data of pressure, wind speed, and wind direction were continually collected. The project goal is to establish the accuracy of the new generation of WSN system and analyze the pressure and wind fluctuation characteristics of the hurricanes and WOW test. Various statistical analysis, including spectral analysis, is performed to study the influence of the corner vortex on the pressure. The result estimates the acceleration effect, separation effect acting on different areas of the roof. The power spectrum density (PSD) plots, one of the outcomes of spectral analysis, corresponds to the strength of the fluctuation on different frequencies of the flow. The WSN system measures air pressure, humidity, temperature, wind speed, and wind direction, where humidity is added to the system for the first time. This paper introduces the hardware comparison between two generations of WSN systems in terms of pressure resolution. The dimensions are also involved in the comparison for pressure sensor case, circuit board, and coordinator. The pressure sensor case WSN system performance analysis shows the comparison of pressure measurement by two generations of the WSN system. The resolution is a 0.1 mbar for the pressure measurement of the new system, which is around 1/25 of the old system. For other measurable values, they all get significant improvements which resolution will be explained. The agreement of spectral analysis results for corner vortices and flow separation is less pronounced between hurricanes and WOW test, but the trends are similar. The wind properties constantly change, leading to the impure PSD plots. Corner vortices at the leeward roof cause the pressure fluctuation along the windward roof edge and lead to the large PSD on the frequency domain. The acceleration effect acting on the roof leeward eliminates pressure fluctuation, but the separation acting on the leeward area increases the pressure fluctuation.