| Popis: |
Wingtip vortices are an important phenomenon in fluid dynamics due to their complex and negative impacts. Despite numerous studies, the current understanding of the inner vortex is very limited, thus a basis for the design of effective wingtip geometry and vortex manipulation is narrow. This work examines the structure of the trailing vortex shed from a swept-tapered wing; analogous to a commercial aircraft topology. Stereoscopic particle imaging velocimetry (sPIV) has been utilised to compare the vortex structure and development through several angles of attack at various downstream stations for a fixed Reynolds number (Re = 1.5 × 106). After correcting for vortex meander, through helicity-based spatial localisation of the vortex core, relationships between the vortex core velocity/vorticity fields, core shape, and turbulent properties have been examined. Subsequently, the vortex is found to exhibit a layered structure with slow linear rates of dissipation indicative of laminar diffusion mechanisms: despite being a turbulent vortex. The turbulent kinetic energy distribution in the vortex signals that relaminarisation of the inner core occurs. Consideration of the streamline curvature around the core, via examination of the local Richardson number, indicated that a laminar core structure had formed within which large scale turbulent eddies could not contribute to the turbulent diffusion of vorticity away from the core. The normalised circulation within the vortex core has been shown to exhibit self-similar behaviour typical of fully developed axisymmetric vortices. |
