Wood transport during high flow events is here treated as an advective–diffusive phenomenon. A theoretical definition of the governing equation is first provided, highlighting the dependence of floating wood diffusion on the adoption of adequate diffusion coefficients. To estimate these coefficients, an experimental investigation on large wood debris was carried out in a channel presenting a weakly sinusoidal plant, employing regular cylinders with various sizes under different flow conditions. For each configuration, a consistent number of trajectories for the floating wood were acquired and processed through imaging techniques, allowing for a statistical analysis of the wood dynamics. The tests showed that floating logs travel at a velocity lower than the water surface one, not completely aligned to the flow direction and tend to disperse streamwise and transversely. Under the assumption that wood dispersion can be derived from the analysis of wood trajectories fluctuations, the longitudinal, transversal and angular diffusion coefficients were computed. Finally, a preliminary dimensional analysis is presented discussing the relevant spatial and temporal scales for these coefficients.

中文翻译：

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浮木扩散系数的实验和理论分析

高流量事件期间的木材运输在这里被视为对流扩散现象。首先提供了控制方程的理论定义，突出了浮木扩散对采用足够扩散系数的依赖性。为了估算这些系数，在一个呈现弱正弦曲线植物的通道中对大型木屑进行了实验研究，使用了不同流量条件下的各种尺寸的规则圆柱体。对于每种配置，通过成像技术获取并处理了一致数量的浮动木材轨迹，从而可以对木材动力学进行统计分析。测试表明，浮木的行进速度低于水面一，没有完全与流动方向对齐，并且倾向于沿流向和横向分散。在可以从木材轨迹波动的分析得出木材色散的假设下，计算了纵向，横向和角度扩散系数。最后，提出了初步的尺寸分析，讨论了这些系数的相关时空尺度。