The instability of oscillatory plane Poiseuille flow
The instability of oscillatory plane Poiseuille flow
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DOI：
10.1017/s002211208200038x
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发表时间：
1982-03
影响因子：
3.7
通讯作者：
C. V. Kerczek
中科院分区：
文献类型：
--
作者：
C. V. Kerczek
用微扰技术研究了压力梯度为时间周期调制的振动平面泊泽维尔流的不稳定性。Floquet指数（即振荡流扰动的复增长率）通过级数展开计算，以振荡流与定常流的速度幅值比为幂，计算定常流扰动的增长率值。结果表明，在稳定流动临界点附近的雷诺数和扰动波数以及施加振荡的频率大于稳定流动中性扰动频率的十分之一时，振荡流动比稳定流动更稳定。当施加振荡频率很高或很低时，非定常流的稳定性略低于定常流。这些结果至少适用于0·25以下的速度幅值。
The instability of oscillatory plane Poiseuille flow, in which the pressure gradient is time-periodically modulated, is investigated by a perturbation technique. The Floquet exponents (i.e. the complex growth rates of the disturbances to the oscillatory flow) are computed by series expansions, in powers of the oscillatory to steady flow velocity amplitude ratio, about the values of the growth rates of the disturbances of the steady flow. It is shown that the oscillatory flow is more stable than the steady flow for values of Reynolds number and disturbance wave number in the vicinity of the steady flow critical point and for values of frequencies of imposed oscillation greater than about one tenth of the frequency of the steady flow neutral disturbance. At very high and low values of imposed oscillation frequency, the unsteady flow is slightly less stable than the steady flow. These results hold for the values of the velocity amplitude ratio at least up to 0·25.