The perturbation method - A novel large-eddy simulation technique to model realistic turbulence: Application to tidal flow
The perturbation method - A novel large-eddy simulation technique to model realistic turbulence: Application to tidal flow
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DOI：
10.1016/j.ocemod.2019.01.007
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发表时间：
2019-03
期刊：
影响因子：
3.2
通讯作者：
A. Brereton;A. Tejada-Martínez;M. Palmer;J. Polton
中科院分区：
文献类型：
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作者：
A. Brereton;A. Tejada-Martínez;M. Palmer;J. Polton
海洋中的湍流主导着热量和盐分以及化学和生物颗粒的垂直移动。因此，湍流模型对于预测生物泵的强度是至关重要的，例如，在生物泵中，二氧化碳从大气中抽出并被困在深海中。获取湍流观测值是一个昂贵的过程，湍流的建模仍然是一个悬而未决的问题。使用最先进的三维流体动力学模型，如大涡模拟和直接数值模拟，来理解平均流驱动的湍流是一种流行的方法。然而，在这种方法中，湍流产生了它自己的平均流量贡献，在某些应用中，这导致了与规定的平均流量的不希望的发散。这里介绍了摄动法。这一技术确保了对规定的平均流量的零发散。结果表明，当使用ADCP平均流数据来描述模式平均流时，该方法在复制观测到的湍流场方面具有很高的精度。预计这种方法的用户友好性质将使非专业人员能够在湍流剖面仪不是易于处理的资源时获得湍流数据。这种模拟方法也为湍流闭合方案的测试建立了一个严格的框架。
Turbulence in the ocean dominates the vertical movement of heat and salt, as well as chemical and biological particulates. The modelling of turbulence is therefore essential to forecast the strength of the biological pump, for example, in which CO2 is drawn out of the atmosphere and trapped in the deep ocean. Obtaining observations of turbulence is an expensive process and the modelling of turbulence still remains an open problem. Using state-of-the-art 3D hydrodynamic models, such as Large-Eddy Simulation and Direct Numerical Simulation, to understand turbulence driven by mean flow is a popular method. However in this approach, the turbulence creates its own mean flow contribution which, in some applications, results in an undesirable divergence from the prescribed mean flow. Here, the perturbation method is introduced. This technique ensures zero divergence to the prescribed mean flow. Results reveal the high level of accuracy this approach has in replicating the observed turbulent field when using ADCP mean current data to prescribe the model mean flow. It is envisaged that the user-friendly nature of this method will enable non-specialists to derive turbulence data when turbulence profilers are not a tractable resource. This modelling approach also sets a rigid framework for the testing of turbulence closure schemes.