Unable to log in or get member pricing? Having trouble changing your password?

Please review our Frequently Asked Questions for complete information on these and other common situations.
 

Vertical Flight Library & Store

Experimental and Computational Investigation of a Stacked RotorWith Unequal Radii

Chloe Johnson, Vasha Sedlacek, Jayant Sirohi, University of Texas at Austin
George Jacobellis, DEVCOM ARL

https://doi.org/10.4050/F-0079-2023-18063

Abstract:
The loads and acoustics of a coaxial, co-rotating, or stacked, rotor with unequal upper and lower rotor radii were explored through measurements and simulations. The upper and lower rotor radii were both set to the nominal radius of 1.108 m, as well as the upper rotor radius to 90% nominal radius and the lower rotor radius to 90% nominal radius, with an axial spacing of 5.27% nominal radius. Simulations of the rotor system were made using the Rotorcraft Comprehensive Analysis System (RCAS) viscous vortex particle method and acoustic predictions were made coupling RCAS with the PSU-WOPWOP and ANOPP2. The simulations were validated with the NASA ideal twist rotor. The most accurate simulations of the stacked rotor were observed using PSU-WOPWOP's tonal noise predictions and the Brooks, Pope, and Marcolini method implemented in ANOPP2 with a maximum sectional Reynolds number to apply untripped conditions. Flow visualization and blade tip vortex tracking revealed that vortex interactions on the upper surface of the lower rotor blade resulted in adverse broadband noise generation. Therefore, the radius of one rotor was decreased to avoid tip vortex interactions, and subsequent measurements and simulations were made at constant thrust conditions of 150 lbf. Total rotor noise was reduced by 4.5 dB with minimal power increases by shortening the lower rotor to 90% nominal radius. This noise reduction was not captured by the simulations, as the vortex interaction with the rotor blade's boundary layer is not incorporated in current broadband models.


Experimental and Computational Investigation of a Stacked RotorWith Unequal Radii

  • Presented at Forum 79
  • 17 pages
  • SKU # : F-0079-2023-18063
  • Electric VTOL

  • Your Price : $30.00
  • Join or log in to receive the member price of $20.00!


VFS member?
Don't add this to your cart just yet!
Be sure to log in first to receive the member price of $20.00!

 
Add To Cart

Add to Wish List

Reward Value:
(60) Member Points

Experimental and Computational Investigation of a Stacked RotorWith Unequal Radii

Authors / Details:
Chloe Johnson, Vasha Sedlacek, Jayant Sirohi, University of Texas at Austin
George Jacobellis, DEVCOM ARL