Streamwise fluctuations of vortex breakdown at high Reynolds numbers
Connelly, Jonathan S.
MetadataShow full item record
This thesis deals with the characterization of the dependence on the flow geometry of the streamwise fluctuations of the stagnation point of vortex breakdown in axisymmetric tubes and over delta wing aircraft. The statistical analysis presented herein shows that in an axisymmetric tube the 'darting' about the mean stagnation point are distributed normally for the two Reynolds numbers: ReD = 230,000 and 300,000 (independently of the Reynolds number in the range noted). The darting over a delta wing is not only non-Gaussian but also exhibits rather large localized fluctuations (Strouhal numbers ranging from 0.04 to 0.1), presumably due to the strong influence of the surrounding flow and the geometrical conditions: increase of circulation along the trailing edge, the abrupt separation of flow at the base of the delta wing, and other protuberances that emerge from the upper and lower surfaces of the wing (support elements in laboratory and stabilizers on delta wing aircraft). It is concluded that the behavior of vortex breakdown is strongly dependent on the surrounding geometry and that only experiments in axisymmetric tubes can provide the purest form of vortex breakdown for numerical simulations and analytical studies towards the understanding of the internal turbulence and its spectrum within the breakdown bubble for theoretical and industrial purposes.
Showing items related by title, author, creator and subject.
Sarpkaya, Turgut (Monterey, California. Naval Postgraduate School, 1970-07-30); NPS-59SL007IAThe results of an experimental investigation of the characteristics of stationary and travelling vortex breakdowns in swirling flow in a diverging cylindrical tube are presented and discussed. Basically, three types of ...
Novak, Francis G. (Monterey, California. Naval Postgraduate School, 1998-09);This thesis deals with non-cavitating swirling flows with vortex breakdown in various tubes. Phenomenological and quantitative investigations were carried out at Reynolds numbers as high as 300,000. It was shown that a ...
Abarca, Sergio F.; Montgomery, Michael T. (American Meteorological Society, 2014-10);Departures from axisymmetric balance dynamics are quantified during a case of secondary eyewall formation. The case occurred in a three-dimensional mesoscale convection-permitting numerical simulation of a tropical ...