An efficient harmonic balance method for unsteady flows in cascades
An efficient harmonic balance method for unsteady flows in cascades
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DOI：
10.1016/j.ast.2013.02.004
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发表时间：
2013-08
影响因子：
5.6
通讯作者：
Huang Huang-Huang;K. Ekici
中科院分区：
文献类型：
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作者：
Huang Huang-Huang;K. Ekici
本文采用时域/频域谐波平衡法研究了叶栅中由叶片自激振动引起的非线性非定常流动。时间周期流是在几个子时间水平上计算的，这些子时间水平在单个周期内等距分布。非定常Navier-Stokes方程中的时间导数项用伪谱算子近似，该算子耦合了不同子时间水平的解。与经典的时间精确方法相比，本技术具有更高的计算效率。此外，采用复杂的周期性边界条件，计算区域可以减少到一个网格，只有一个叶片在叶栅中，这进一步提高了计算效率。利用伪谱算子和伪时间推进，可以将问题处理为稳态，并可以采用局部时间步进、隐式残差平滑和多重网格等加速收敛技术。为了证明该技术的效率和准确性，我们提出了第十个标准和第十一个标准的结果。
In this paper, nonlinear unsteady flows in cascades arising from self-excited blade vibrations are investigated using a mixed time/frequency domain harmonic balance technique. The time-periodic flow is computed at several sub-time levels that are equally spaced over a single period. The time derivative term in the unsteady Navier–Stokes equations is approximated by a pseudo-spectral operator, which couples solutions at different sub-time levels. Compared to the classical time-accurate approach, the present technique enjoys an improved computational efficiency. In addition, using complex periodic boundary conditions, the computational domain can be reduced to a grid spanning only a single blade in the cascade, which further improves the computational efficiency. With the use of the pseudo-spectral operator and pseudo-time marching, the problem can be treated as steady state and convergence acceleration techniques such as local time stepping, implicit residual smoothing and multigrid can be used. To demonstrate the efficiency and accuracy of the technique, we present results for the Tenth Standard and the Eleventh Standard Configurations.