Helicopter and tilt-rotor blades produce complex
vortical flow fields that interact with the nacelles,
wings, fuselage, and the ground. Rotorcraft designers
need an efficient computational tool that can model
these vortical flow fields and accurately predict the
aerodynamic performance of rotary-wing vehicles.
The purpose of this project is to develop a computational
tool with which to model the complex flow
fields around rotors and bodies. In an industry design
environment, turnaround time must be reduced to a
level at which design cycles can be conducted within
schedule and cost. Therefore, the computational tool
must be efficient and easy to use.
With Ames' funding, Sukra Helitek Inc. developed
a software tool called Rot3DC, which simulates
the flow field around rotary-wing vehicles. The
method employs a graphical user interface to model
either isolated rotors or rotor and fuselage problems,
including ground interference. Rot3DC solves the
Navier-Stokes equations on unstructured grids with a
simple, but effective, momentum-source representation
for the rotor blades. This momentum-source
rotor-blade model allows for highly efficient solutions
of rotor flow fields.
Figure 1 shows a sample aerodynamic solution
from the Rot3DC code for a V-22 tilt-rotor landing on
the deck of an aircraft carrier. This figure demonstrates
the complicated interactions between the rotor
downwash, the wings of the V-22, and the deck of
the ship. Despite these complex flow-field features,
the Rot3DC code can model these solutions in a
matter of hours on a high-end personal computer.
This rapid turnaround and simplified problem setup
make Rot3DC well-suited for helicopter design
applications. Indeed, the Boeing Company has
licensed Rot3DC and is using it to model the
Comanche helicopter and V-22 tilt rotor.
Sukra Helitek Inc. plans to upgrade the Rot3DC
computer code to include a higher-fidelity unsteady
rotor model and solution-adaptive grids for improved
modeling of rotor wakes. These modifications should
improve the overall analytical accuracy while
retaining the ease of use and rapid turnaround of the
original Rot3DC software package.
Point of Contact: R. Strawn
(650) 604-4510
rstrawn@mail.arc.nasa.gov
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