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Enhanced viscous flow drag reduction using acoustic excitation
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Nagel, Robert T. |
| Copyright Year | 1987 |
| Description | Proper acoustic excitation of a single large-eddy break-up device can increase the resulting drag reduction and, after approximately 40 to 50 delta downstream, provide net drag reduction. Precise optimization of the input time delay, amplitude and response threshold is difficult but possible to achieve. Drag reduction is improved with optimized conditions. The possibility of optimized processing strongly suggests a mechanism which involves interaction of the acoustic waves and large eddies at the trailing edge of the large eddy break-up device. Although the mechanism for spreading of this phenomenon is unknown, it is apparent that the drag reduction effect does tend to spread spanwise as the flow convects downstream. The phenomenon is not unique to a particular blade configuration or flow velocity, although all data have been obtained at relatively low Reynolds numbers. The general repeatibility of the results for small configuration changes serves as verification of the phenomenon. |
| File Size | 712831 |
| Page Count | 21 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19870017694 |
| Archival Resource Key | ark:/13960/t7dr7r56x |
| Language | English |
| Publisher Date | 1987-01-20 |
| Access Restriction | Open |
| Subject Keyword | Fluid Mechanics And Heat Transfer Augmentation Low Reynolds Number Viscous Drag Acoustic Excitation Turbine Blades Aerodynamic Configurations Drag Reduction Vortices Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
