Onset and Prediction of Orbital Motions of Streamwise Vortices
Abstract
Wing tips and aircraft appendages generate streamwise oriented vortices that are an unavoidable consequence of lifting flight and a source of induced drag for aircraft in isolation. Should these vortices be generated upstream of an aircraft, their close interaction with or impingement upon downstream wings may improve their lift and drag characteristics by negating the adverse effects of trailing vortex generation. However, in this scenario vortex wing interactions may also lead to unsteady aerodynamic loads, which can arise from dramatic changes to the vortex structure due to the destabilizing upstream influence of the solid body. In addition to stability considerations associated with the placement of the body relative to the incoming vortex, streamwise vortices can exhibit meandering spiral motions that grow in amplitude as they advect downstream, which could potentially negate any aerodynamic benefit on the downstream wing or body and become a source of unsteady buffeting. The root mechanism of this vortex meandering remains incompletely understood and is a point of controversy in the comparison of wind tunnel measurements against computational fluid dynamics simulations. Spiraling vortex structures can also occur in unbounded flows in the case of trailing vortices generated by moving wings, where transverse vortex distortions initiated by wing tip oscillations may transition into an orbital rotation. The current lack of insight into the varied effects of vortex displacements, variations in the vortex core structure along its axis, and solid boundaries motivates the present theoretical investigation into the stability and motion of finite core streamwise vortices and their orbital motions. Fundamental modeling insight into the inception of orbital vortex motions and their downstream evolution may offer the means to reconcile existing experimental and numerical investigations, as well as suggest the basis for a physics based control strategy.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 14, 2022
- Source ID
- FA95501910095
Entities
People
- Justin W Jaworski
Organizations
- Air Force Office of Scientific Research
- Lehigh University
- United States Air Force