Predicting the wake structure of the HART II rotor using the vorticity transport model

Mary E. Kelly, Richard Brown

Research output: Contribution to conferencePaper

4 Citations (Scopus)

Abstract

Brown's Vorticity Transport Model has been used to predict the wake structure and resultant blade loading of the rotor that was studied during the HART II experimental programme. The descending flight condition of the experiment yields significant high-frequency content to the blade loading due to the presence of blade-vortex interactions. PIV images of the wake structure were compared against numerical predictions of the detailed geometry of the rotor wake using three different computational resolutions of the flow. This was done to investigate the origin of inaccuracies exposed in an earlier study of the system in capturing the effects of blade vortex interactions on the loading on the rotor. The predicted positions of the vortex cores agree with measured data to within a fraction of the blade chord, and the strength of the vortices is preserved to well downstream of the rotor, essentially independently of the resolution of the calculation. Nevertheless the amplitude of the loading impulses induced on the blade by vortex interaction are strongly influenced by the resolution of the calculation through the effect of cell density on the minimum vortex core size that can be supported. It would appear thus that the inaccuracies in predicting the high-frequency loading on the rotor are not due to any inherent deficiency in the representation of the wake, although viscous effects may need to be considered in future in order to decouple the vortex core size from the cell size, but rather due to the inherent deficiencies of the lifting line approach used to model the blade aerodynamics.
LanguageEnglish
Number of pages17
Publication statusPublished - 16 Sep 2008
Event34th European Rotorcraft Forum - Liverpool, UK
Duration: 16 Sep 200819 Sep 2008

Conference

Conference34th European Rotorcraft Forum
CityLiverpool, UK
Period16/09/0819/09/08

Fingerprint

Wake
Vorticity
Blade
Rotor
Vortex flow
Rotors
Vortex
Turbomachine blades
Model
Interaction
Cell Size
Aerodynamics
Chord or secant line
Impulse
Geometry
Predict
Line
Prediction
Cell
Experiments

Keywords

  • vorticity transport model
  • wake structure
  • hart II rotor
  • blade-vortex interactions
  • bvi
  • computational fluid dynamics
  • cfd

Cite this

Kelly, M. E., & Brown, R. (2008). Predicting the wake structure of the HART II rotor using the vorticity transport model. Paper presented at 34th European Rotorcraft Forum, Liverpool, UK, .
Kelly, Mary E. ; Brown, Richard. / Predicting the wake structure of the HART II rotor using the vorticity transport model. Paper presented at 34th European Rotorcraft Forum, Liverpool, UK, .17 p.
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abstract = "Brown's Vorticity Transport Model has been used to predict the wake structure and resultant blade loading of the rotor that was studied during the HART II experimental programme. The descending flight condition of the experiment yields significant high-frequency content to the blade loading due to the presence of blade-vortex interactions. PIV images of the wake structure were compared against numerical predictions of the detailed geometry of the rotor wake using three different computational resolutions of the flow. This was done to investigate the origin of inaccuracies exposed in an earlier study of the system in capturing the effects of blade vortex interactions on the loading on the rotor. The predicted positions of the vortex cores agree with measured data to within a fraction of the blade chord, and the strength of the vortices is preserved to well downstream of the rotor, essentially independently of the resolution of the calculation. Nevertheless the amplitude of the loading impulses induced on the blade by vortex interaction are strongly influenced by the resolution of the calculation through the effect of cell density on the minimum vortex core size that can be supported. It would appear thus that the inaccuracies in predicting the high-frequency loading on the rotor are not due to any inherent deficiency in the representation of the wake, although viscous effects may need to be considered in future in order to decouple the vortex core size from the cell size, but rather due to the inherent deficiencies of the lifting line approach used to model the blade aerodynamics.",
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Kelly, ME & Brown, R 2008, 'Predicting the wake structure of the HART II rotor using the vorticity transport model' Paper presented at 34th European Rotorcraft Forum, Liverpool, UK, 16/09/08 - 19/09/08, .

Predicting the wake structure of the HART II rotor using the vorticity transport model. / Kelly, Mary E.; Brown, Richard.

2008. Paper presented at 34th European Rotorcraft Forum, Liverpool, UK, .

Research output: Contribution to conferencePaper

TY - CONF

T1 - Predicting the wake structure of the HART II rotor using the vorticity transport model

AU - Kelly, Mary E.

AU - Brown, Richard

PY - 2008/9/16

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N2 - Brown's Vorticity Transport Model has been used to predict the wake structure and resultant blade loading of the rotor that was studied during the HART II experimental programme. The descending flight condition of the experiment yields significant high-frequency content to the blade loading due to the presence of blade-vortex interactions. PIV images of the wake structure were compared against numerical predictions of the detailed geometry of the rotor wake using three different computational resolutions of the flow. This was done to investigate the origin of inaccuracies exposed in an earlier study of the system in capturing the effects of blade vortex interactions on the loading on the rotor. The predicted positions of the vortex cores agree with measured data to within a fraction of the blade chord, and the strength of the vortices is preserved to well downstream of the rotor, essentially independently of the resolution of the calculation. Nevertheless the amplitude of the loading impulses induced on the blade by vortex interaction are strongly influenced by the resolution of the calculation through the effect of cell density on the minimum vortex core size that can be supported. It would appear thus that the inaccuracies in predicting the high-frequency loading on the rotor are not due to any inherent deficiency in the representation of the wake, although viscous effects may need to be considered in future in order to decouple the vortex core size from the cell size, but rather due to the inherent deficiencies of the lifting line approach used to model the blade aerodynamics.

AB - Brown's Vorticity Transport Model has been used to predict the wake structure and resultant blade loading of the rotor that was studied during the HART II experimental programme. The descending flight condition of the experiment yields significant high-frequency content to the blade loading due to the presence of blade-vortex interactions. PIV images of the wake structure were compared against numerical predictions of the detailed geometry of the rotor wake using three different computational resolutions of the flow. This was done to investigate the origin of inaccuracies exposed in an earlier study of the system in capturing the effects of blade vortex interactions on the loading on the rotor. The predicted positions of the vortex cores agree with measured data to within a fraction of the blade chord, and the strength of the vortices is preserved to well downstream of the rotor, essentially independently of the resolution of the calculation. Nevertheless the amplitude of the loading impulses induced on the blade by vortex interaction are strongly influenced by the resolution of the calculation through the effect of cell density on the minimum vortex core size that can be supported. It would appear thus that the inaccuracies in predicting the high-frequency loading on the rotor are not due to any inherent deficiency in the representation of the wake, although viscous effects may need to be considered in future in order to decouple the vortex core size from the cell size, but rather due to the inherent deficiencies of the lifting line approach used to model the blade aerodynamics.

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Kelly ME, Brown R. Predicting the wake structure of the HART II rotor using the vorticity transport model. 2008. Paper presented at 34th European Rotorcraft Forum, Liverpool, UK, .