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arXiv 1707.02876math.OCcs.SYeess.SYphysics.comp-phphysics.flu-dyn
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在线动态模式分解用于时变系统

Online dynamic mode decomposition for time-varying systems

Princeton University(普林斯顿大学);Florida State University(佛罗里达州立大学)

Hao Zhang, Clarence W. Rowley, Eric A. Deem, Louis N. Cattafesta

AI总结:

本文提出一种高效的在线动态模式分解方法,用于实时更新时变系统动态,通过秩1更新计算精确DMD矩阵,适用于时间变化系统,并在风洞实验中验证了其有效性。

摘要:

动态模式分解(DMD)是一种流行的模态分解、流体分析和降阶建模技术。在系统随时间变化的情况下,希望能够实时更新系统的描述。本文提供了一种高效的实时计算DMD的方法,能够在新数据到来时更新系统的动态近似。该算法不需要存储过去的数据,并利用秩1更新计算精确的DMD矩阵。可以引入一个加权因子,使旧数据的权重较小,使该方法特别适合于时变系统。该方法的变种也可用于在线计算'窗口DMD',其中仅使用最近的数据。该方法的效率与几种现有DMD算法进行了比较:对于状态维度小于约200的问题,所提算法在实时计算中是最高效的,并且比标准DMD算法快几个数量级。该方法在多个示例中得到了验证,包括一个时变线性系统和一个更复杂的使用风洞实验数据的示例。特别是,我们展示了该方法在捕捉平板上流动中不稳分离泡表面压力测量动态方面的有效性。

英文摘要:

Dynamic mode decomposition (DMD) is a popular technique for modal decomposition, flow analysis, and reduced-order modeling. In situations where a system is time varying, one would like to update the system's description online as time evolves. This work provides an efficient method for computing DMD in real time, updating the approximation of a system's dynamics as new data becomes available. The algorithm does not require storage of past data, and computes the exact DMD matrix using rank-1 updates. A weighting factor that places less weight on older data can be incorporated in a straightforward manner, making the method particularly well suited to time-varying systems. A variant of the method may also be applied to online computation of "windowed DMD", in which only the most recent data are used. The efficiency of the method is compared against several existing DMD algorithms: for problems in which the state dimension is less than about~200, the proposed algorithm is the most efficient for real-time computation, and it can be orders of magnitude more efficient than the standard DMD algorithm. The method is demonstrated on several examples, including a time-varying linear system and a more complex example using data from a wind tunnel experiment. In particular, we show that the method is effective at capturing the dynamics of surface pressure measurements in the flow over a flat plate with an unsteady separation bubble.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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