The effect of vortex generators on helicopter drag was investigated in a wind tunnel test. An array of counterrotating vortex generators was mounted on the rear ramp of a heavy-class helicopter model, slightly downstream of the fuselage upsweep. The wind tunnel campaign also included tests with a radome positioned upstream of the vortex generators to evaluate the robustness of the vortex generators. At cruise angle of attack, a drag reduction of about 2% with respect to the complete helicopter configuration was measured for the baseline fuselage configuration with the vortex generator array installed. The range of angles of attack and sideslip where the vortex generators were effective for drag reduction was established. The addition of a radome mounted upstream on the fuselage lower side renders the vortex generators ineffective. However, for the model attitudes where the vortex generators were ineffective, the vortex generators did not increase helicopter drag. Steady and unsteady pressures measured on the fuselage rear ramp revealed the flow behavior due to the presence of the vortex generators.

Robustness and limits of vortex generator effectiveness in helicopter drag reduction

ZANOTTI, ALEX;DROANDI, GIOVANNI;AUTERI, FRANCO;GIBERTINI, GIUSEPPE;
2016-01-01

Abstract

The effect of vortex generators on helicopter drag was investigated in a wind tunnel test. An array of counterrotating vortex generators was mounted on the rear ramp of a heavy-class helicopter model, slightly downstream of the fuselage upsweep. The wind tunnel campaign also included tests with a radome positioned upstream of the vortex generators to evaluate the robustness of the vortex generators. At cruise angle of attack, a drag reduction of about 2% with respect to the complete helicopter configuration was measured for the baseline fuselage configuration with the vortex generator array installed. The range of angles of attack and sideslip where the vortex generators were effective for drag reduction was established. The addition of a radome mounted upstream on the fuselage lower side renders the vortex generators ineffective. However, for the model attitudes where the vortex generators were ineffective, the vortex generators did not increase helicopter drag. Steady and unsteady pressures measured on the fuselage rear ramp revealed the flow behavior due to the presence of the vortex generators.
2016
Aerospace Engineering; Materials Science (all); Mechanical Engineering; Mechanics of Materials
File in questo prodotto:
File Dimensione Formato  
ZANOA03-16.pdf

Accesso riservato

Descrizione: Paper
: Publisher’s version
Dimensione 1.38 MB
Formato Adobe PDF
1.38 MB Adobe PDF   Visualizza/Apri
ZANOA_OA_01-16.pdf

Open Access dal 02/04/2018

Descrizione: Paper open access
: Post-Print (DRAFT o Author’s Accepted Manuscript-AAM)
Dimensione 1.22 MB
Formato Adobe PDF
1.22 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/997739
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 5
  • ???jsp.display-item.citation.isi??? 3
social impact