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Wall pressure unsteadiness and side loads in overexpanded rocket nozzles
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Baars, Woutijn J. McDaniels, David M. Tinney, Charles E. Brown, Andrew M. Ruf, Joseph H. |
| Copyright Year | 2012 |
| Description | Surveys of both the static and dynamic wall pressure signatures on the interior surface of a sub-scale, cold-flow and thrust optimized parabolic nozzle are conducted during fixed nozzle pressure ratios corresponding to FSS and RSS states. The motive is to develop a better understanding for the sources of off-axis loads during the transient start-up of overexpanded rocket nozzles. During FSS state, pressure spectra reveal frequency content resembling SWTBLI. Presumably, when the internal flow is in RSS state, separation bubbles are trapped by shocks and expansion waves; interactions between the separated flow regions and the waves produce asymmetric pressure distributions. An analysis of the azimuthal modes reveals how the breathing mode encompasses most of the resolved energy and that the side load inducing mode is coherent with the response moment measured by strain gauges mounted upstream of the nozzle on a flexible tube. Finally, the unsteady pressure is locally more energetic during RSS, albeit direct measurements of the response moments indicate higher side load activity when in FSS state. It is postulated that these discrepancies are attributed to cancellation effects between annular separation bubbles. |
| File Size | 9812294 |
| Page Count | 30 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20120014182 |
| Archival Resource Key | ark:/13960/t1bk6c68d |
| Language | English |
| Publisher Date | 2012-01-01 |
| Access Restriction | Open |
| Subject Keyword | Spacecraft Propulsion And Power Rocket Nozzles Static Pressure Wall Pressure Internal Flow Pressure Distribution Pressure Ratio Strain Gages Elastic Waves Frequencies Separated Flow Loads Forces Dynamic Pressure Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
