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Flexible launch vehicle stability analysis using steady and unsteady computational fluid dynamics
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Bartels, Robert E. |
| Copyright Year | 2012 |
| Description | Launch vehicles frequently experience a reduced stability margin through the transonic Mach number range. This reduced stability margin can be caused by the aerodynamic undamping one of the lower-frequency flexible or rigid body modes. Analysis of the behavior of a flexible vehicle is routinely performed with quasi-steady aerodynamic line loads derived from steady rigid aerodynamics. However, a quasi-steady aeroelastic stability analysis can be unconservative at the critical Mach numbers, where experiment or unsteady computational aeroelastic analysis show a reduced or even negative aerodynamic damping.Amethod of enhancing the quasi-steady aeroelastic stability analysis of a launch vehicle with unsteady aerodynamics is developed that uses unsteady computational fluid dynamics to compute the response of selected lower-frequency modes. The response is contained in a time history of the vehicle line loads. A proper orthogonal decomposition of the unsteady aerodynamic line-load response is used to reduce the scale of data volume and system identification is used to derive the aerodynamic stiffness, damping, and mass matrices. The results are compared with the damping and frequency computed from unsteady computational aeroelasticity and from a quasi-steady analysis. The results show that incorporating unsteady aerodynamics in this way brings the enhanced quasi-steady aeroelastic stability analysis into close agreement with the unsteady computational aeroelastic results. |
| File Size | 1350348 |
| Page Count | 7 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20120013662 |
| Archival Resource Key | ark:/13960/t48q1109r |
| Language | English |
| Publisher Date | 2012-08-01 |
| Access Restriction | Open |
| Subject Keyword | Fluid Mechanics And Thermodynamics Stability Tests Flexible Bodies Approximation Computational Fluid Dynamics Steady Flow Ares 1 Launch Vehicle Quasi-steady States Navier-stokes Equation Launch Vehicles Flow Distribution Unsteady Aerodynamics Frequency Distribution Aeroelasticity Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
