摘要
为了计算的省时性，ＩＡＰ近岸海流数值模式采用了分解算法，即将控制方程分解为３个过程并用不同的时间步长进行积分。文章在此基础上对分解后的控制方程作局地线性化，得到了适合不同过程的开边界条件。对于适应过程，控制方程变换为等价的表示沿不同方向传播波动的特征方程。传出计算区域的波动用特征方程来描述，而传入波动则由无反射边界条件来消除。对于演变过程，求出了解析形式的通解。在流出点上，边界条件可以借助解析解由上一时刻区域内部或边界上的已知值求得；而在流入点上，边值保持定常。对于耗散过程，不需要边界条件。最后对所提出的开边界条件进行了数值检验，结果是令人满意的。
The barotropic numerical shelf sea model of the institute of AtmosphericPhysics (LAP), Chinese Academy of Sciences, is outlined first. For computing economy,a splitting method is applied of dividing the governing equations into three stageswhich are integrated with different time-steps. Open boundary conditions suitable forthe different stages are derived from the locally linearized versions of the splitgoverning equations. For the adjustment stage, the governing equations are convertedto an equivalent set of characteristic equations which represent waves propagating intoor out of the computational. domain. The outgoing waves are described bycharacteristic equations, while the incoming waves are suppressed by a nonreflectingboundary condition. For the development stage, general analytical solutions are found.At outflow points the boundary values at the upper time-level are obtained from dataat the present time-level within and on the boundary via the analytical solutions, whilethe boundary values at inflow points remain constant in time. For theforcing-dissipation stage, no boundary conditions are necessary. Numerical verificationof the proposed open boundary conditions is described; the results are satisfactory.
出处
《热带海洋》
CSCD
1999年第1期38-45,共8页
基金
国家科委攀登计划"气候动力学和气候预测理论的研究"资助!PD27
关键词
近岸
海流
数值模式
分解算法
开边界条件
offshore current, numerical model, splitting method, open boundaryconditions
