Flowfield Downstream of Circular Cylinders Immersed Within Thick Boundary Layers
| Autor: | Peter J. Disimile, John M. Davis, Norman Toy |
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| Rok vydání: | 2009 |
| Předmět: | |
| Zdroj: | AIAA Journal. 47:1461-1469 |
| ISSN: | 1533-385X 0001-1452 |
| DOI: | 10.2514/1.36085 |
| Popis: | With little data currently available, designers of physical models of aircraft engine nacelles have little basis to determine the size of geometric detail required to provide a sufficient representation of the actual specimen. The current study presents an experimental investigation into the minimum geometry size required for accurate aircraft engine simulator design by measuring the turbulent shear flow downstream of two-dimensional surface-mounted circular cylinders of various sizes. Cylinder diameters D of 5,10, 20, and 40 mm were individually flush-mounted on the test-section floor of a wind tunnel specifically designed to simulate an aircraft engine nacelle, which operated at a freestream velocity and turbulence intensity of 8.4 m/s and 1%, respectively. The turbulent boundary layer approaching each cylinder had a thickness δ 99 of 39 mm, yielding examined δ 99 /D ratios of 0.98,1.97, 3.93, and 7.86. Velocity profiles were measured using hot-wire anemometry at several locations downstream of each cylinder. The results showed that the separated shear-layer location was observed to significantly differ from that reported for sharp-edged obstructions, with the shear layer maintaining a constant height for δ 99 /D ratios of 3.93 and 7.86. |
| Databáze: | OpenAIRE |
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