This study investigates the energy harvesting prospects of self-sustained flow oscillations emanating from grazing flow over a rectangular cavity by employing experimental and computational methods. Two cavity geometries with length-to-depth ratios of 2 and 3, exposed to an incoming flow of 30 m/s, were selected for the purpose. The power spectral density of the baseline cavity flows showed the presence of high-amplitude peaks whose frequencies agreed to those estimated from Rossiter’s feedback model. For energy harvesting, a piezoelectric beam was placed perpendicular to the aft wall and its natural frequency tuned to match closely with the dominant frequencies of the cavity flow oscillations. From the experiments, an average and maximum instantaneous power of 21.11 and 284.18 µW was recorded for the cavity with L/D = 2 whereas for the cavity with L/D = 3 the corresponding values were 32.16 and 403.46 µW respectively. Time-frequency analysis showed the forcing of the beam at the cavity oscillation frequency and the substantial increase in the amplitude of beam vibrations when this frequency was close to the natural frequency of the beam.

这项研究通过实验和计算方法研究了掠过矩形腔体上的水流而产生的自持式水流振荡的能量收集前景。为此，选择了两个腔室几何结构，它们的长深比为2和3，暴露于30 m / s的进入流量。基线腔流的功率谱密度显示存在高振幅峰，其频率与从罗西特的反馈模型估计的频率一致。为了收集能量，将压电束垂直于后壁放置，并将其固有频率调整为与腔体流动振荡的主频率紧密匹配。从实验中可以看出，具有L的腔的平均瞬时最大功率和最大瞬时功率为21.11和284.18 µW。/ D  = 2，而对于L / D  = 3的腔，相应的值分别为32.16和403.46 µW。时频分析表明，在谐振腔振荡频率处，梁受到强迫，当该频率接近梁的固有频率时，梁的振动幅度会大大增加。