Dual-cylindrical Surface Pressure Distribution Of The Simultaneous Measurement And Pulsating Aerodynamic Characteristics

Flow around single circular cylinder and grouped circular cylinders is the most typical problem which is paid much attention in the research of blunt body flow. In this paper, based on the existing research in the literatures, flow interference between two circular cylinders in three representative arrangements(in tandem, side-by-side and staggered)—especially the characteristics of fluctuating aerodynamic forces—was investigated experimentally by simultaneous multi-pressure measurement.In present experiment, a 32-channel simultaneous multi-pressure measurement system was developed and the dynamic characteristics of each channel which were used in the program of the correction for distorted pressure signals through the pressure transfer pipe were calibrated. The reliability of the system was verified by measuring the fluctuating pressure distribution of single circular cylinder and comparing the results with those in the literatures.Based on the results of the measurements of fluctuating pressure distribution, the following aspects of flow around two circular cylinders were carefully studied:1. The characteristics of mean and fluctuating surface pressure distribution;2. The characteristics of mean and fluctuating aerodynamic forces;3. The relationship between the frequencies of fluctuating aerodynamic forces and vortex shedding by the power spectrum analysis;4. The correlation between the fluctuating aerodynamic forces of two circular cylinders;5. The correlation between the fluctuating pressure at separation point of two circular cylinders;6. The correlation between fluctuating pressure at separation point and those around the whole circumference, and the correlation between fluctuating aerodynamic forces and fluctuating pressure around the whole circumference;7. The instantaneous pressure distribution;8. The statistical characteristics of the fluctuating aerodynamic forces analysed by PDF(probability distribution function).The jump between different flow patterns at certain critical position was discovered again in present experiment, and the flow patterns were relatively steady between the critical positions. In the three arrangements, the maximum of the fluctuating aerodynamic forces all appeared at the position when the distance between the two circular cylinders was appreciably longer than critical value. The correlation analysis of the fluctuating aerodynamic forces and the fluctuating pressure distribution showed that the fluctuating aerodynamic forces can be expressed by the fluctuating pressure at special positions.