CFD investigation was carried out to study the heat transfer enhancement characteristics of air flow inside a circular tube with a partially decaying and partly swirl flow. Four combinations of tube with twisted-tape inserts, the half-length upstream twisted-tape condition (HLUTT), the half-length downstream twisted-tape condition (HLDTT), the full-length twisted tape (FLTT), and the plain tube (PT) with three different twist parameters (, 0.27, and 0.38) have been investigated. 3D numerical simulation was performed for an analysis of heat transfer enhancement and fluid flow for turbulent regime. The results of CFD investigations of heat transfer and friction characteristics are presented for the FLTT, HLUTT, and the HLDTT in comparison with the PT case.

Recent trends in distributed sensing networks have generated significant interest in the design of scalable micro-power generators. One such device exploits the galloping oscillations of a prism to harness energy from a moving fluid. Performance of galloping harvester's depends on the flow patterns around the prism, which, in turn, depend on its geometry and the Reynolds number of the flow. In this letter, we demonstrate that the useful range of the galloping instability can be extended by attaching a rigid splitter plate to the rear face of the prism. The plate provides a secondary flow reattachment point, which serves to improve the oscillation amplitude and power output of the generator. Experimental results demonstrate as much as 67% power enhancement for some prism geometries and a significant reduction in the cut-in wind speed of the generator.

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