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Crosswind shear gradient affect on wake vortices
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Ahmad, Nashat N. Proctor, Fred H. |
| Copyright Year | 2011 |
| Description | Parametric simulations with a Large Eddy Simulation (LES) model are used to explore the influence of crosswind shear on aircraft wake vortices. Previous studies based on field measurements, laboratory experiments, as well as LES, have shown that the vertical gradient of crosswind shear, i.e. the second vertical derivative of the environmental crosswind, can influence wake vortex transport. The presence of nonlinear vertical shear of the crosswind velocity can reduce the descent rate, causing a wake vortex pair to tilt and change in its lateral separation. The LES parametric studies confirm that the vertical gradient of crosswind shear does influence vortex trajectories. The parametric results also show that vortex decay from the effects of shear are complex since the crosswind shear, along with the vertical gradient of crosswind shear, can affect whether the lateral separation between wake vortices is increased or decreased. If the separation is decreased, the vortex linking time is decreased, and a more rapid decay of wake vortex circulation occurs. If the separation is increased, the time to link is increased, and at least one of the vortices of the vortex pair may have a longer life time than in the case without shear. In some cases, the wake vortices may never link. |
| File Size | 950332 |
| Page Count | 8 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20110013647 |
| Archival Resource Key | ark:/13960/t2b907x2h |
| Language | English |
| Publisher Date | 2011-06-27 |
| Access Restriction | Open |
| Subject Keyword | Aerodynamics Wind Direction Attitude Inclination Large Eddy Simulation Vortices Derivation Wakes Nonlinearity Trajectories Gradients Descent Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
