caa a22 4500 60619911X CHVBK 20210128100937.0 cr unu---uuuuu 210128e20151101xx s 000 0 eng 10.1007/s00348-015-2079-3 doi (NATIONALLICENCE)springer-10.1007/s00348-015-2079-3 On the transient dynamics of the wake and trajectory of free falling cones with various apex angles [Elektronische Daten] [Ali Hamed, Yaqing Jin, Leonardo Chamorro] The early free fall stages of cones with a density ratio 1.18 and apex angles of $$30^{\circ }$$ 30 ∘ , $$45^{\circ }$$ 45 ∘ , $$60^{\circ }$$ 60 ∘ , and $$90^{\circ }$$ 90 ∘ were studied using a wireless 3-axis gyroscope and accelerometer to describe the cone 3D motions, while particle image velocimetry was used to capture the induced flow in the near wake. The Reynolds number based on the cones diameter and the velocity at which the cone reaches the first local velocity maximum is found to consistently set the limit between two distinctive states. Relatively rapid growth in the cone nutation and departure from the vertical axis is observed after this Re is reached. Sequences of vertical velocity, swirling strength, LES-decomposed velocity, and pressure fields show the formation and growth of a large and initially symmetric recirculation bubble at the cone base. Those also highlight the presence of a symmetric 3D vortex rollup dominating the near wake in the early stages of the fall. A shear layer develops at the edge of the wake and manifests in the periodic shedding of Kelvin-Helmholtz vortices that, due to the nature of the recirculation bubble, reorganize to constitute a part of the rollup. Later in the fall, the wake loses symmetry and shows high population of vortical structures leading to turbulence. The asymmetric wake leads to strong interactions between the flow field and the cone evidenced by the shedding of a part of the 3D large-scale vortex rollup. This shedding process along with the cone rotation around its own axis provides a possible explanation of the helical wake structure observed in other studies. Springer-Verlag Berlin Heidelberg, 2015 Hamed Ali Department of Mechanical Science and Engineering, University of Illinois, 61801, Urbana, IL, USA aut Jin Yaqing Department of Mechanical Science and Engineering, University of Illinois, 61801, Urbana, IL, USA aut Chamorro Leonardo Department of Mechanical Science and Engineering, University of Illinois, 61801, Urbana, IL, USA aut Experiments in Fluids Springer Berlin Heidelberg 56/11(2015-11-01), 1-10 0723-4864 56:11<1 2015 56 348 https://doi.org/10.1007/s00348-015-2079-3 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00348-015-2079-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hamed Ali Department of Mechanical Science and Engineering, University of Illinois, 61801, Urbana, IL, USA aut NATIONALLICENCE 700 1- Jin Yaqing Department of Mechanical Science and Engineering, University of Illinois, 61801, Urbana, IL, USA aut NATIONALLICENCE 700 1- Chamorro Leonardo Department of Mechanical Science and Engineering, University of Illinois, 61801, Urbana, IL, USA aut NATIONALLICENCE 773 0- Experiments in Fluids Springer Berlin Heidelberg 56/11(2015-11-01), 1-10 0723-4864 56:11<1 2015 56 348