The Eulerian–Lagrangian model ORSA2D_WT is employed for the simulation of uncongested wood transport, with reference to a field experiment that studied the motion of regular and unbranched cylindrical wooden samples. The model calculates the entrainment, transport and deposition of large wood elements by computing the hydrodynamic forces exerted by the flow. The experimental log positions and displacements are taken as a reference for the first application of the numerical model to a real-scale test case. Special attention is paid to the presence of large boulders, which interact with floating wood and are represented as nearly 3D elements in the numerical domain, to take into account their effect both on the flow and on the logs. The comparison between the field data and the numerical simulation shows that the model fails to replicate exactly each log trajectory. However, when the focus moves to the behaviour of the entire group of logs, the model appears to simulate quite well the areas where logs are more prone to stop. The wood density implemented in the model strongly affect the results in terms of single log displacement, emphasizing the importance of the correct estimation of this parameter for large wood simulation.

中文翻译：

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里恩茨河未阻塞木材运输的数值模拟

欧拉-拉格朗日模型ORSA2D_WT用于模拟未拥挤的木材运输，并参考了研究规则和不分支的圆柱状木质样品运动的野外实验。该模型通过计算水流施加的水动力来计算大型木材元素的夹带，运输和沉积。实验测井的位置和位移作为数值模型首次应用于实际测试案例的参考。要特别注意大石块的存在，它们与浮木相互作用并在数值域中表示为近3D元素，以考虑它们对流动和原木的影响。现场数据和数值模拟之间的比较表明，该模型无法精确地复制每个测井轨迹。但是，当焦点转移到整个原木组的行为时，该模型似乎可以很好地模拟原木更容易停止的区域。该模型中实现的木材密度极大地影响了单对数位移的结果，从而强调了正确估计此参数对于大型木材仿真的重要性。