A two-dimensional computational model is develope for the calulation of tides, storm surges and otherlong-period waves in coastal and shelf waters. The Partial differental equations are approximated by two sets of dif...A two-dimensional computational model is develope for the calulation of tides, storm surges and otherlong-period waves in coastal and shelf waters. The Partial differental equations are approximated by two sets of difference equations on a space-staggered grid system. Both sets are explicit with one set for water level and x-component velocity, and another for water level and y-component velocity. These two sets are used successively for stepby-step solution in time. An analytical investigation on the linearized sets of the difference equations indicates that thecomputational scheme is unconditionally stable. The model is of second order accuracy both in space and in time andconserves mass and momentum. Simulations of surface elevation caused by periodic forcing in one-opening rectangularbasin with flat topography and by steady wind stress in the basin with flat or slope topography show that the computed results are in excellent agreement with the corresponding analytic solutions. The steady-tate wind-induced setupin a ofed basin with discontinuous topography computed with the present model are also in excellent agreement withthe results from Leendertse's model. Finally, the model is applied to hindcast a storm surge in the South China Seaand reproduces the surge elevation satisfactorily.展开更多
针对文献[Xu R et al.,IEEE Trans.Biomed.Eng.,2014]的多尺度图像分解模型,该文提出了Alternating Direction Implicit (ADI)格式下的多尺度图像分解算法,并证明了在该模型下ADI格式的收敛性和稳定性,进一步,通过对不同图像的数值实验...针对文献[Xu R et al.,IEEE Trans.Biomed.Eng.,2014]的多尺度图像分解模型,该文提出了Alternating Direction Implicit (ADI)格式下的多尺度图像分解算法,并证明了在该模型下ADI格式的收敛性和稳定性,进一步,通过对不同图像的数值实验,验证了该文提出的算法具有更好的纹理提取效果.展开更多
在周期边界条件下,首先提出了求解二维等离子体麦克斯韦方程组的交替方向隐式时域有限差分(alternating direction implicit finite-difference time-domain,ADI-FDTD)格式,然后利用离散能量法,给出了该格式的先验估计,并由此证明了该...在周期边界条件下,首先提出了求解二维等离子体麦克斯韦方程组的交替方向隐式时域有限差分(alternating direction implicit finite-difference time-domain,ADI-FDTD)格式,然后利用离散能量法,给出了该格式的先验估计,并由此证明了该格式在最大模意义下具有时空二阶收敛性。在此基础上,为了提高数值结果的精度,利用截断误差的渐近展开式对所提出的ADI-FDTD格式做Richardson外推,得到了时空四阶精度的算法。最后通过数值实验验证了理论结果。展开更多
研究了直驱风电场次同步振荡分析的降阶模型,提出了基于交替方向隐式(alternating direction implicit,ADI)的平衡截断方法。首先,根据直驱式永磁同步风电机组的数学表征搭建风电场的数学模型,采用ADI方法迭代求解李亚普诺夫方程,得到...研究了直驱风电场次同步振荡分析的降阶模型,提出了基于交替方向隐式(alternating direction implicit,ADI)的平衡截断方法。首先,根据直驱式永磁同步风电机组的数学表征搭建风电场的数学模型,采用ADI方法迭代求解李亚普诺夫方程,得到可控的格莱姆矩阵与可观的格莱姆矩阵;然后,采用平衡截断的方法得到降阶模型;通过对比全阶模型与降阶模型的时域仿真波形、Bode图、计算耗时以及次同步振荡模式,验证了方法的有效性。仿真结果表明,降阶模型与全阶模型具有很好的一致性,同时计算速度提高,降阶阶数大大降低。展开更多
文摘A two-dimensional computational model is develope for the calulation of tides, storm surges and otherlong-period waves in coastal and shelf waters. The Partial differental equations are approximated by two sets of difference equations on a space-staggered grid system. Both sets are explicit with one set for water level and x-component velocity, and another for water level and y-component velocity. These two sets are used successively for stepby-step solution in time. An analytical investigation on the linearized sets of the difference equations indicates that thecomputational scheme is unconditionally stable. The model is of second order accuracy both in space and in time andconserves mass and momentum. Simulations of surface elevation caused by periodic forcing in one-opening rectangularbasin with flat topography and by steady wind stress in the basin with flat or slope topography show that the computed results are in excellent agreement with the corresponding analytic solutions. The steady-tate wind-induced setupin a ofed basin with discontinuous topography computed with the present model are also in excellent agreement withthe results from Leendertse's model. Finally, the model is applied to hindcast a storm surge in the South China Seaand reproduces the surge elevation satisfactorily.
文摘针对文献[Xu R et al.,IEEE Trans.Biomed.Eng.,2014]的多尺度图像分解模型,该文提出了Alternating Direction Implicit (ADI)格式下的多尺度图像分解算法,并证明了在该模型下ADI格式的收敛性和稳定性,进一步,通过对不同图像的数值实验,验证了该文提出的算法具有更好的纹理提取效果.
文摘在周期边界条件下,首先提出了求解二维等离子体麦克斯韦方程组的交替方向隐式时域有限差分(alternating direction implicit finite-difference time-domain,ADI-FDTD)格式,然后利用离散能量法,给出了该格式的先验估计,并由此证明了该格式在最大模意义下具有时空二阶收敛性。在此基础上,为了提高数值结果的精度,利用截断误差的渐近展开式对所提出的ADI-FDTD格式做Richardson外推,得到了时空四阶精度的算法。最后通过数值实验验证了理论结果。
文摘研究了直驱风电场次同步振荡分析的降阶模型,提出了基于交替方向隐式(alternating direction implicit,ADI)的平衡截断方法。首先,根据直驱式永磁同步风电机组的数学表征搭建风电场的数学模型,采用ADI方法迭代求解李亚普诺夫方程,得到可控的格莱姆矩阵与可观的格莱姆矩阵;然后,采用平衡截断的方法得到降阶模型;通过对比全阶模型与降阶模型的时域仿真波形、Bode图、计算耗时以及次同步振荡模式,验证了方法的有效性。仿真结果表明,降阶模型与全阶模型具有很好的一致性,同时计算速度提高,降阶阶数大大降低。
