Experiments, numerical simulations, and linear theory are used to explore the kinetic energy density of waves generated by oscillating topography in a nonlinear stratification. Initially, generated waves are evanescent but then pass through a turning depth and into a propagating region. A technique for calculating kinetic energy density indirectly via the density perturbation field measured using synthetic schlieren is tested to assess the validity of the calculation. To establish the indirect calculation’s range of validity, numerical simulations were performed to compare the indirect calculation to an estimate of kinetic energy calculated from local velocity components (referred to here as the standard calculation). In addition, the standard calculation is applied to the velocity field determined via linear theory, which defines the fluid velocity using similar assumptions to the indirect calculation of kinetic energy. Both calculation methods show similar trends in the average kinetic energy density present in propagating waves as a function of Froude number, topography height, and distance from topography to the turning depth. Local comparisons of kinetic energy density from the indirect and standard calculations identify regions where the two methods compare well. Additionally, a correlation between linear theory and numerical simulations is presented to evaluate the range of applicability of the linear theory.

中文翻译：

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在实验、模拟和线性理论中渐逝于传播内波

实验、数值模拟和线性理论用于探索非线性分层中振荡地形产生的波的动能密度。最初，生成的波是渐逝的，但随后会穿过转向深度并进入传播区域。测试了一种通过使用合成纹影测量的密度扰动场间接计算动能密度的技术，以评估计算的有效性。为了建立间接计算的有效性范围，进行了数值模拟以将间接计算与根据局部速度分量计算出的动能估计值进行比较（此处称为标准计算）。此外，标准计算适用于通过线性理论确定的速度场，它使用类似于动能间接计算的假设来定义流体速度。两种计算方法都显示出传播波中存在的平均动能密度作为弗劳德数、地形高度和从地形到转向深度的距离的函数的相似趋势。来自间接计算和标准计算的动能密度的局部比较确定了两种方法比较好的区域。此外，还提出了线性理论和数值模拟之间的相关性，以评估线性理论的适用范围。以及从地形到转弯深度的距离。来自间接计算和标准计算的动能密度的局部比较确定了两种方法比较好的区域。此外，还提出了线性理论和数值模拟之间的相关性，以评估线性理论的适用范围。以及从地形到转弯深度的距离。来自间接计算和标准计算的动能密度的局部比较确定了两种方法比较好的区域。此外，还提出了线性理论和数值模拟之间的相关性，以评估线性理论的适用范围。