Instability mechanisms in meandering streamwise vortex pairs of upswept afterbody wakes
نویسندگان
چکیده
Wakes of upswept afterbodies are often characterized by counter-rotating streamwise vortex pairs which meander in space. One application concerns aft regions cargo aircraft, a relatively flat base. Here we consider canonical configuration comprised cylinder with basal surface. The resulting longitudinal vortices, much closer to each other than wing-tip can adversely influence paratrooper and drop operations as well trailing aircraft. unsteady dynamics these vortices examined using spatio-temporally resolved Large-Eddy Simulations (LES) stability considerations. Emphasis is placed on understanding the potential instability responsible for meandering, was observed, quantified at representative location downstream body. then successfully mapped matched Batchelor pair, spatial temporal analyses performed both computational domain. Both reveal dipole structures associated |m|=1 elliptic modes dominant afterbody vortices. A short-wave mode found dominate meandering motion pair; this stable case an isolated vortex. Further, strain due axial velocity plays key role therefore breakdown. low frequency unstable (Strouhal number StD≃0.3 based diameter) consistent spectral analysis LES. Stability very low-wavenumber do not exhibit any suggesting absence Crow instability.
منابع مشابه
Global Mode Behavior of the Streamwise Velocity in Wakes
We characterize experimentally and numerically the two-dimensional structure of the global mode of the longitudinal component of the velocity in flow behind obstacles of different geometrical shapes. Measurements in a low velocity water tunnel and numerical simulations of
متن کاملStreamwise vortex structure in plane mixing layers
The development of three-dimensional motions in a plane mixing layer was investigated experimentally. It is shown that superimposed on the primary, spanwise vortex structure there is a secondary, steamwise vortex structure. Three aspects of this secondary structure were studied. First, the spanwise vortex instability that generates the secondary structure was characterized by measurements of th...
متن کاملTransient Growth for Streak-Streamwise Vortex Interactions
We analyze transient growth due to the linear interaction between streaks and streamwise vortices. We obtain initial perturbations which give optimal initial and total energy growth, characterize the dependence of the dynamics on the initial distribution of perturbation energy, and compare with results from pseudospectra analysis.
متن کاملSTREAMWISE VORTEX INSTABILITY AND HYPERSONIC BOUNDARY-LAYER TRANSITION ON THE HYPER-2000 A Thesis
Matsumura, Shin. Master of Science in Aeronautics and Astronautics, Purdue University, December, 2003. Streamwise Vortex Instability and Hypersonic BoundaryLayer Transition on the Hyper-2000. Major Professor: Steven P. Schneider. Despite the closely coupled multidisciplinary design of hypersonic airbreathing vehicles, the boundary layer transition mechanisms that are important on the forebody a...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: European Journal of Mechanics B-fluids
سال: 2022
ISSN: ['1873-7390', '0997-7546']
DOI: https://doi.org/10.1016/j.euromechflu.2022.07.006