Predicting blade vortex interaction, airloads and acoustics using the vorticity transport model

Mary E. Kelly, Karthikeyan Duraisamy, Richard Brown

Research output: Contribution to conferencePaper

30 Citations (Scopus)

Abstract

Interactions between the blades and vortical structures within the wake of a helicopter rotor are a significant source of impulsive loading and noise, particularly in descending flight. Advances in the prediction and understanding of such blade vortex interactions have been aided in recent years by the extensive experimental dataset made available through the HART test programme. Brown's Vorticity Transport Model was used to predict the rotor blade loading, the resultant wake system and the acoustic noise radiation for the HART II rotor. The vorticity conserving properties of the Vorticity Transport Model allow the detailed wake features that are associated with blade vortex interactions to be resolved. The experimental airload data, in particular the higher harmonic loading associated with blade vortex interactions, is matched well by the computations. The computed vorticity distribution in the wake also shows good correlation with the experimentally measured vortex positions. Including a representation of the fuselage within the computation yields marked improvement in the prediction of the vortex positions compared to similar calculations with an isolated rotor. An accoustic analysis, based on a Ffowcs-Williams Hawkings approach, is able to predict accurately the locations of the sound pressure maxima and the upstream attenuation of the sound radiated by the rotor. The principal discrepancies in airload, vortex position and acoustic prediction are confined almost exclusively to the rear of the advancing side of the rotor and, if errors in measuring the blade deflection can be discounted, may be due to minor inaccuracies in modelling the roll-up of the wake.

Conference

Conference9th American Helicopter Society Aeromechanics Specialists' Meeting
CitySan Francisco, California
Period23/01/0825/01/08

Fingerprint

Vorticity
Blade
Rotor
Wake
Vortex
Acoustics
Vortex flow
Rotors
Interaction
Turbomachine blades
Prediction
Acoustic waves
Model
Predict
Helicopter rotors
Fuselages
Helicopter
Acoustic noise
Attenuation
Deflection

Keywords

  • blade vortex interaction
  • vorticity transport model
  • HART test programme
  • acoustic noise radiation
  • rotor blade loading
  • accoustic analysis

Cite this

Kelly, M. E., Duraisamy, K., & Brown, R. (2008). Predicting blade vortex interaction, airloads and acoustics using the vorticity transport model. Paper presented at 9th American Helicopter Society Aeromechanics Specialists' Meeting, San Francisco, California, .
Kelly, Mary E. ; Duraisamy, Karthikeyan ; Brown, Richard. / Predicting blade vortex interaction, airloads and acoustics using the vorticity transport model. Paper presented at 9th American Helicopter Society Aeromechanics Specialists' Meeting, San Francisco, California, .19 p.
@conference{0ce620897b6149f5a893eebeeb77b60b,
title = "Predicting blade vortex interaction, airloads and acoustics using the vorticity transport model",
abstract = "Interactions between the blades and vortical structures within the wake of a helicopter rotor are a significant source of impulsive loading and noise, particularly in descending flight. Advances in the prediction and understanding of such blade vortex interactions have been aided in recent years by the extensive experimental dataset made available through the HART test programme. Brown's Vorticity Transport Model was used to predict the rotor blade loading, the resultant wake system and the acoustic noise radiation for the HART II rotor. The vorticity conserving properties of the Vorticity Transport Model allow the detailed wake features that are associated with blade vortex interactions to be resolved. The experimental airload data, in particular the higher harmonic loading associated with blade vortex interactions, is matched well by the computations. The computed vorticity distribution in the wake also shows good correlation with the experimentally measured vortex positions. Including a representation of the fuselage within the computation yields marked improvement in the prediction of the vortex positions compared to similar calculations with an isolated rotor. An accoustic analysis, based on a Ffowcs-Williams Hawkings approach, is able to predict accurately the locations of the sound pressure maxima and the upstream attenuation of the sound radiated by the rotor. The principal discrepancies in airload, vortex position and acoustic prediction are confined almost exclusively to the rear of the advancing side of the rotor and, if errors in measuring the blade deflection can be discounted, may be due to minor inaccuracies in modelling the roll-up of the wake.",
keywords = "blade vortex interaction, vorticity transport model, HART test programme, acoustic noise radiation, rotor blade loading, accoustic analysis",
author = "Kelly, {Mary E.} and Karthikeyan Duraisamy and Richard Brown",
year = "2008",
month = "1",
day = "23",
language = "English",
note = "9th American Helicopter Society Aeromechanics Specialists' Meeting ; Conference date: 23-01-2008 Through 25-01-2008",

}

Kelly, ME, Duraisamy, K & Brown, R 2008, 'Predicting blade vortex interaction, airloads and acoustics using the vorticity transport model' Paper presented at 9th American Helicopter Society Aeromechanics Specialists' Meeting, San Francisco, California, 23/01/08 - 25/01/08, .

Predicting blade vortex interaction, airloads and acoustics using the vorticity transport model. / Kelly, Mary E.; Duraisamy, Karthikeyan; Brown, Richard.

2008. Paper presented at 9th American Helicopter Society Aeromechanics Specialists' Meeting, San Francisco, California, .

Research output: Contribution to conferencePaper

TY - CONF

T1 - Predicting blade vortex interaction, airloads and acoustics using the vorticity transport model

AU - Kelly, Mary E.

AU - Duraisamy, Karthikeyan

AU - Brown, Richard

PY - 2008/1/23

Y1 - 2008/1/23

N2 - Interactions between the blades and vortical structures within the wake of a helicopter rotor are a significant source of impulsive loading and noise, particularly in descending flight. Advances in the prediction and understanding of such blade vortex interactions have been aided in recent years by the extensive experimental dataset made available through the HART test programme. Brown's Vorticity Transport Model was used to predict the rotor blade loading, the resultant wake system and the acoustic noise radiation for the HART II rotor. The vorticity conserving properties of the Vorticity Transport Model allow the detailed wake features that are associated with blade vortex interactions to be resolved. The experimental airload data, in particular the higher harmonic loading associated with blade vortex interactions, is matched well by the computations. The computed vorticity distribution in the wake also shows good correlation with the experimentally measured vortex positions. Including a representation of the fuselage within the computation yields marked improvement in the prediction of the vortex positions compared to similar calculations with an isolated rotor. An accoustic analysis, based on a Ffowcs-Williams Hawkings approach, is able to predict accurately the locations of the sound pressure maxima and the upstream attenuation of the sound radiated by the rotor. The principal discrepancies in airload, vortex position and acoustic prediction are confined almost exclusively to the rear of the advancing side of the rotor and, if errors in measuring the blade deflection can be discounted, may be due to minor inaccuracies in modelling the roll-up of the wake.

AB - Interactions between the blades and vortical structures within the wake of a helicopter rotor are a significant source of impulsive loading and noise, particularly in descending flight. Advances in the prediction and understanding of such blade vortex interactions have been aided in recent years by the extensive experimental dataset made available through the HART test programme. Brown's Vorticity Transport Model was used to predict the rotor blade loading, the resultant wake system and the acoustic noise radiation for the HART II rotor. The vorticity conserving properties of the Vorticity Transport Model allow the detailed wake features that are associated with blade vortex interactions to be resolved. The experimental airload data, in particular the higher harmonic loading associated with blade vortex interactions, is matched well by the computations. The computed vorticity distribution in the wake also shows good correlation with the experimentally measured vortex positions. Including a representation of the fuselage within the computation yields marked improvement in the prediction of the vortex positions compared to similar calculations with an isolated rotor. An accoustic analysis, based on a Ffowcs-Williams Hawkings approach, is able to predict accurately the locations of the sound pressure maxima and the upstream attenuation of the sound radiated by the rotor. The principal discrepancies in airload, vortex position and acoustic prediction are confined almost exclusively to the rear of the advancing side of the rotor and, if errors in measuring the blade deflection can be discounted, may be due to minor inaccuracies in modelling the roll-up of the wake.

KW - blade vortex interaction

KW - vorticity transport model

KW - HART test programme

KW - acoustic noise radiation

KW - rotor blade loading

KW - accoustic analysis

UR - http://www.vtol.org/index.html

UR - http://www.vtol.org/pdf/jan08_aeromechanicsProgram.pdf

M3 - Paper

ER -

Kelly ME, Duraisamy K, Brown R. Predicting blade vortex interaction, airloads and acoustics using the vorticity transport model. 2008. Paper presented at 9th American Helicopter Society Aeromechanics Specialists' Meeting, San Francisco, California, .