基于有限体积法的河网水动力并行计算模型

针对具有干河床、急缓流态交替的河网水动力模拟,采用MUSCL-Hancock有限体积格式离散Saint-Venant方程组,运用汊点水位预测-校正法处理河网汊点连接条件,建立了断面与河道完全数值解耦的复杂河网水动力模型。运用OpenMP和OpenACC编程模式分别实现了CPU,GPU并行计算。采用经典算例对模型计算精度进行了验证,采用珠三角河网实际算例对不同并行计算方式的加速效果进行了分析。算例研究表明,该模型具有良好的稳定性和计算效率,可适用于陡坡河道水动力模拟,具有较好的推广应用价值。

A Parallel Finite-volume Method for Hydrodynamic Modeling of River Network

A hydrodynamic model of complex river network in which the computational cross-sections and reaches are fully decoupled is constructed for river network with dry beds and transition between supercritical and subcritical flows. The MUSCL-Hancock finite-volume scheme is adopted to discrete the Saint-Venant equations, and the method of Junction-Point Water Stage Prediction and Correction (JPWSPC) is used to calculate the hydrodynamic relations at junctions. The OpenMP and OpenACC applications are used to realize CPU-based and GPU-based parallel computing, respectively. Model accuracy is validated by benchmark cases with exact solutions, and the performance of parallel computing is demonstrated by real flood simulation of the Pearl River Delta. Results show that the proposed model is stable and effective, and is applicable for hydrodynamic simulation for steep river, thus has bright application prospects.