连续弯曲河段水-热耦合复杂多维系统数值模拟

In the Inner Mongolia reaches of the Yellow River, ice flood still threats the persons living on both banks. After the factors affecting the ice flood were analyzed, the hydraulic and thermal factors which control the whole ice evolution process are taken as research focus. As a result, the hydro-thermal coupled complex multidimensional system in the continuous curved reaches is set as the object. A fully three-dimensional hydrodynamic model will be developed. It’s expected that the model can improve the flow simulation accuracy and reveal how the complicated hydrodynamic phenomena affect the ice transportation. In addition, due to the heavy leakage in the reaches, the heat exchange between the water and river bed is no longer a pure heat conduction process. Using the multi-disciplinary crossing research methods, a partial differential equation will be explored that can depict the compound heat transfer process including both thermal conduction and convection. After that, a water temperature model will be established. It’s expected that this model can further reveal the water heat budget. This research can improve the current theory of simulating flow and water temperature, and is well worth doing. It can supply an important basement for developing a full river ice model.

黄河内蒙古段的凌汛给两岸人民造成的威胁至今还未彻底解除。通过分析各种凌情影响因素，确定水力与热力因素自始至终主导着河冰演变过程。因此，本课题以连续弯曲河段水-热耦合复杂多维系统为对象，通过建立全三维水动力模型，提高水流模拟精度，揭示连续弯曲河段的复杂水动力过程对冰凌输移过程的驱动机制；同时，考虑到该河段大量渗漏补给地下水，河水与河床的热交换不再是纯粹的热传导过程，通过多学科相互交叉渗透研究，探索性地提出描述河床复合传热过程（热传导和热对流）的偏微分方程，提高水－河床界面热交换通量的模拟精度，建立水温模型，更深入地揭示水体热量收支状况。本研究可完善现有河冰模型中水流与水温的模拟理论与方法，具有重要的理论研究价值，为进一步建立完整河冰数值模型打下基础。

首先推导了三维非静压水动力学控制方程，采用有限差分法离散控制方程，将求解过程分为静压步和非静压步，建立了水动力学模型。然后，采用显格式离散温度传输方程，将水动力学方程与水温方程耦合，建立了一个水-热耦合模型。黄河内蒙古头道拐附近的连续弯曲河段，在每年凌汛期极易卡冰结坝，项目即以此河段为研究对象，利用所建模型模拟了此河段的流场和温度场，并用实测水温验证了模型，证明了本文所建模型的有效性。