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Fourier functional analysis for unsteady aerodynamic modeling
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Chin, Suei Lan, C. Edward |
| Copyright Year | 1991 |
| Description | A method based on Fourier analysis is developed to analyze the force and moment data obtained in large amplitude forced oscillation tests at high angles of attack. The aerodynamic models for normal force, lift, drag, and pitching moment coefficients are built up from a set of aerodynamic responses to harmonic motions at different frequencies. Based on the aerodynamic models of harmonic data, the indicial responses are formed. The final expressions for the models involve time integrals of the indicial type advocated by Tobak and Schiff. Results from linear two- and three-dimensional unsteady aerodynamic theories as well as test data for a 70-degree delta wing are used to verify the models. It is shown that the present modeling method is accurate in producing the aerodynamic responses to harmonic motions and the ramp type motions. The model also produces correct trend for a 70-degree delta wing in harmonic motion with different mean angles-of-attack. However, the current model cannot be used to extrapolate data to higher angles-of-attack than that of the harmonic motions which form the aerodynamic model. For linear ramp motions, a special method is used to calculate the corresponding frequency and phase angle at a given time. The calculated results from modeling show a higher lift peak for linear ramp motion than for harmonic ramp motion. The current model also shows reasonably good results for the lift responses at different angles of attack. |
| File Size | 2180630 |
| Page Count | 101 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19910008751 |
| Archival Resource Key | ark:/13960/t3fz26448 |
| Language | English |
| Publisher Date | 1991-02-01 |
| Access Restriction | Open |
| Subject Keyword | Aerodynamics Dynamic Response Aerodynamic Drag Pitching Moments Forced Vibration Fourier Analysis Functional Analysis Lift Aircraft Models Moment Distribution Delta Wings Unsteady Aerodynamics Mathematical Models Harmonic Motion Angle of Attack Aerodynamic Characteristics Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
