关键词: 明渠湍流, 混沌理论, 相空间重构, 延迟时间, 关联维度, Lyapunov指数, Kolmogrov熵

Abstract: Open channel flume experiment was performed in an attempt to reveal the chaotic characteristics of turbulent flow. The turbulent flow velocity field attenuating along the flow direction was measured using Acoustic Doppler Velocimetry (ADV). In the light of the chaos theory, phase space reconstruction of the turbulent velocity time series was performed to calculate the corresponding chaotic characteristic parameters (including time delay, correlation dimension, Lyapunov exponent, and Kolmogrov entropy). Results demonstrated that the turbulence in open channel is of chaotic characteristics. After installing the turbulence control board, the chaotic characteristics of turbulence are continuously weakened along the upward direction of water depth and the water flow direction. The aforementioned chaotic characteristic parameters were further compared with the statistical average parameters, and results proved that the chaotic characteristic parameters reflect the law of the dissipation and perish of turbulent vortex structures in space.

Key words: turbulent flow in open channel, chaos theory, phase space reconstruction, time delay, correlation dimension, Lyapunov exponent, Kolmogrov entropy