An implicit method for coupled flow-body dynamics
An implicit method for coupled flow-body dynamics
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DOI：
10.1016/j.jcp.2008.01.021
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发表时间：
2008-05
期刊：
影响因子：
--
通讯作者：
S. Alben
中科院分区：
文献类型：
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作者：
S. Alben
本文提出了一种计算流体耦合动力学的有效方法。时间步进是隐式的，并使用迭代方法（预处理GMRES）来求解流体方程。该预处理器解决了一个解耦的版本的方程，其中只涉及带状矩阵的逆，并需要一个小的迭代次数，每个时间步。我们用这种方法来探讨一个简单的垂直运动的椭圆体的水平运动的不稳定性：拍动和上升。在这两种情况下，水平运动的线性不稳定性在临界雷诺数以上，导致稳定的振荡状态。压力对稳定粘性力起着不稳定的作用，振荡时间尺度由外部扑动或内部流体耦合来设定。后者降低了雷诺数的不稳定阈值。
We propose an efficient method for computing coupled flow–body dynamics. The time-stepping is implicit, and uses an iterative method (preconditioned GMRES) to solve the flow–body equations. The preconditioner solves a decoupled version of the equations which involves only the inversion of banded matrices, and requires a small number of iterations per time step. We use the method to probe the instability to horizontal motions of an elliptical body with simple vertical motions: flapping and rising. In both cases a linear instability to horizontal motion sets in above a critical Reynolds number, leading to a stable oscillatory state. The pressure forces play a destabilizing role against the stabilizing viscous forces, with oscillatory time scales set by either external flapping or the intrinsic flow–body coupling. The latter lowers the instability threshold in Reynolds number.