Statistical modelling for prediction of axis-switching in rectangular jets
| dc.contributor.author | Tipnis, T. J. | - |
| dc.contributor.author | Knowles, Kevin | - |
| dc.contributor.author | Bray, Derek | - |
| dc.date.accessioned | 2014-01-23T05:01:18Z | |
| dc.date.available | 2014-01-23T05:01:18Z | |
| dc.date.issued | 2013-08-01T00:00:00Z | - |
| dc.description.abstract | Rectangular nozzles are increasingly used for modern military aircraft propulsion installations, including the roll nozzles on the F-35B vertical/short take-off and landing strike fighter. A peculiar phenomenon known as axis-switching is generally observed in such non-axisymmetric nozzle flows during which the jet spreads faster along the minor axis compared to the major axis. This might affect the under-wing stores and aircraft structure. A computational fluid dynamics study was performed to understand the effects of changing the upstream nozzle geometry on a rectangular free jet. A method is proposed, involving the formulation of an equation based upon a statistical model for a rectangular nozzle with an exit aspect ratio (ARe) of 4; the variables under consideration (for a constant nozzle pressure ratio (NPR)) being inlet aspect ratio (ARi) and length of the contraction section. The jet development was characterised using two parameters: location of the cross-over point (Xc) and the difference in the jet half-velocity widths along the major and minor axes (ΔB30). Based on the observed results, two statistical models were formulated for the prediction of axis-switching; the first model gives the location of the cross-over point, while the second model indicates the occurrence of axis-switching for the given configuration. | en_UK |
| dc.identifier.citation | Tipnis TJ, Knowles K, Bray D. (2013) Statistical modelling for prediction of axis-switching in rectangular jets. Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering. Volume 227, Issue 8, August 2013, pp. 1325-37 | |
| dc.identifier.issn | 0954-4100 | - |
| dc.identifier.uri | http://dx.doi.org/10.1177/0954410012456511 | - |
| dc.identifier.uri | http://dspace.lib.cranfield.ac.uk/handle/1826/8089 | |
| dc.language.iso | en_UK | - |
| dc.publisher | Professional Engineering Publishing | en_UK |
| dc.title | Statistical modelling for prediction of axis-switching in rectangular jets | en_UK |
| dc.type | Article | - |