Imperial College London

ProfessorPeterSchmid

Faculty of Natural SciencesDepartment of Mathematics

Chair in Applied Mathematics
 
 
 
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Contact

 

peter.schmid

 
 
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Location

 

753Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Edstrand:2016:10.1017/jfm.2016.440,
author = {Edstrand, AM and Davis, TB and Schmid, PJ and Taira, K and Cattafesta, LN},
doi = {10.1017/jfm.2016.440},
journal = {Journal of Fluid Mechanics},
title = {On the mechanism of trailing vortex wandering},
url = {http://dx.doi.org/10.1017/jfm.2016.440},
volume = {801},
year = {2016}
}

RIS format (EndNote, RefMan)

TY  - JOUR
AB - The mechanism of trailing vortex wandering has long been debated and is often attributed to either wind-tunnel effects or an instability. Using particle image velocimetry data obtained in the wake of a NACA0012 airfoil, we remove the effect of wandering from the measured velocity field and, through a triple decomposition, recover the coherent wandering motion. Based on this wandering motion, the most energetic structures are computed using the proper orthogonal decomposition (POD) and exhibit a helical mode with an azimuthal wavenumber of |m|=1 whose kinetic energy grows monotonically in the downstream direction. To investigate the nature of the vortex wandering, we perform a spatial stability analysis of a matched Batchelor vortex. The primary stability mode is found to be marginally stable and nearly identical in both size and structure to the leading POD mode. The strikingly similar structure, coupled with the measured energy growth, supports the proposition that the vortex wandering is the result of an instability. We conclude that the cause of the wandering is the non-zero radial velocity of the |m|=1 mode on the vortex centreline, which acts to transversely displace the trailing vortex, as observed in experiments. However, the marginal nature of the stability mode prevents a definitive conclusion regarding the specific type of instability.
AU - Edstrand,AM
AU - Davis,TB
AU - Schmid,PJ
AU - Taira,K
AU - Cattafesta,LN
DO - 10.1017/jfm.2016.440
PY - 2016///
SN - 0022-1120
TI - On the mechanism of trailing vortex wandering
T2 - Journal of Fluid Mechanics
UR - http://dx.doi.org/10.1017/jfm.2016.440
UR - http://hdl.handle.net/10044/1/39077
VL - 801
ER -