TY - GEN
T1 - Experimental investigation of flows with three-dimensional separation
AU - Balthazar, Michael
AU - Gross, Andreas
AU - Fasel, Hermann F.
N1 - Publisher Copyright:
© 2015 American Institute of Aeronautics and Astronautics Inc. All rights reserved.
PY - 2014
Y1 - 2014
N2 - The mean flow topology for flows with three-dimensional separation can be highly complex and the unsteady fluid dynamics are largely unexplored. Water tunnel experiments and direct numerical simulations were carried out to obtain insight into the three-dimensional separation topology for submarine-like geometries. Particle image velocimetry was employed for obtaining quantitative mean flow data. A hemisphere-cylinder model and a model of the Virginia Tech “ellipsoid” geometry were developed for investigating three-dimensional separation. At 10 degrees angle of attack, a large laminar separation bubble developed on the nose of the hemisphere-cylinder model. The bubble was shedding intermittently. When the angle of attack was increased to 30 degrees two leeward vortices were generated and the bubble shedding was reduced. The “ellipsoid” model did not exhibit a laminar nose separation bubble at angle of attack. However, for combined roll and yaw angles or, alternatively, angle-of-attack/side-slip angle combinations highly asymmetric configurations of the leeward vortices were obtained. This asymmetry may explain the static roll-instability observed in earlier experiments at Virginia Tech for mixed roll/yaw maneuvers.
AB - The mean flow topology for flows with three-dimensional separation can be highly complex and the unsteady fluid dynamics are largely unexplored. Water tunnel experiments and direct numerical simulations were carried out to obtain insight into the three-dimensional separation topology for submarine-like geometries. Particle image velocimetry was employed for obtaining quantitative mean flow data. A hemisphere-cylinder model and a model of the Virginia Tech “ellipsoid” geometry were developed for investigating three-dimensional separation. At 10 degrees angle of attack, a large laminar separation bubble developed on the nose of the hemisphere-cylinder model. The bubble was shedding intermittently. When the angle of attack was increased to 30 degrees two leeward vortices were generated and the bubble shedding was reduced. The “ellipsoid” model did not exhibit a laminar nose separation bubble at angle of attack. However, for combined roll and yaw angles or, alternatively, angle-of-attack/side-slip angle combinations highly asymmetric configurations of the leeward vortices were obtained. This asymmetry may explain the static roll-instability observed in earlier experiments at Virginia Tech for mixed roll/yaw maneuvers.
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M3 - Conference contribution
AN - SCOPUS:84938243831
T3 - 52nd Aerospace Sciences Meeting
BT - 52nd Aerospace Sciences Meeting
PB - American Institute of Aeronautics and Astronautics Inc.
T2 - 52nd Aerospace Sciences Meeting 2014
Y2 - 13 January 2014 through 17 January 2014
ER -