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International Journal of Rotating Machinery
Volume 2012 (2012), Article ID 543096, 12 pages
Research Article

Predicting Unsteady Loads in Marine Propulsor Crashback Using Large Eddy Simulation

Department of Aerospace Engineering and Mechanics, University of Minnesota, Minneapolis, MN 55455, USA

Received 15 January 2012; Accepted 17 May 2012

Academic Editor: Jules W. Lindau

Copyright © 2012 Hyunchul Jang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Propulsor crashback is an off-design operating condition where a propulsor rotates in the reverse direction to yield negative thrust. Crashback is characterized by the interaction of the free stream with the reverse flow generated by propulsor rotation. This causes a highly unsteady vortex ring which leads to flow separation and unsteady forces and moments on the blades. Large eddy simulation (LES) is performed for marine propulsors in crashback for various configurations and advance ratios and validated against experiments. The predictive capability of LES as a tool for propulsor crashback is demonstrated on an open propulsor, open propulsor with a submarine hull, and ducted propulsor with and without stator blades. LES is in good agreement with experiments for the mean and RMS levels, and spectra of the unsteady loads on the propulsors.