The effect of flow separation and turbulence on the performance of a jet pump in oscillatory flows is investigated. A jet pump is a static device whose shape induces asymmetric hydrodynamic end effects when placed in an oscillatory flow. This will result in a time-averaged pressure drop which can be used to suppress acoustic streaming in closed-loop thermoacoustic devices. An experimental setup is used to measure the time-averaged pressure drop as well as the acoustic power dissipation across two different jet pump geometries in a pure oscillatory flow. The results are compared against published numerical results where flow separation was found to have a negative effect on the jet pump performance in a laminar flow. Using hot-wire anemometry the onset of flow separation is determined experimentally and the applicability of a critical Reynolds number for oscillatory pipe flows is confirmed for jet pump applications. It is found that turbulence can lead to a reduction of flow separation and hence, to an improvement in jet pump performance compared to laminar oscillatory flows.

中文翻译：

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热声应用喷射泵中的流动分离和湍流

研究了流动分离和湍流对振荡流中喷射泵性能的影响。喷射泵是一种静态装置，当置于振荡流中时，其形状会引起不对称的流体动力学末端效应。这将导致时间平均压降，可用于抑制闭环热声设备中的声流。实验装置用于测量纯振荡流中两种不同喷射泵几何形状的时间平均压降以及声功率耗散。将结果与已发表的数值结果进行比较，发现流动分离对层流中的喷射泵性能有负面影响。使用热线风速测量法通过实验确定流动分离的开始，并且确认了振荡管流的临界雷诺数适用于喷射泵应用。研究发现，与层流振荡流相比，湍流会导致流动分离的减少，从而提高喷射泵的性能。