Po-Wei Chen
(Advisor: Prof. Lakshmi Sankar]

will defend a doctoral thesis entitled

A PHYSICS-BASED MODEL FOR INFLOW CHARACTERISTICS OF

MULTI-ROTOR CONFIGURATIONS

On

Wednesday, August 4 at 9 a.m.

https://bluejeans.com/550894873

Abstract
A physics-based model for modeling helicopter and UAV rotor configurations, previously developed for isolated rotors and coaxial rotors in hover and forward flight has been extended to more general multi-rotor configurations. Simulations for coaxial, and tandem rotor configurations have been done for a number of low and high Reynolds number configurations, and comparisons with test data have been made.  The physics behind the rotor interactions has been explored through visualization and analysis of vortex wake trajectories and inflow velocity distributions.   

As part of this effort, a fast off-body velocity field analysis that employs GPU processors has been implemented. In addition to computation of inflow velocity field above or below the rotor disks, this approach is capable of rapidly computing and visualizing velocity field on any user specified plane. In many helicopters design studies, the adverse interactions caused by the main rotor wake should be considered in the placement of horizontal and vertical stabilizers, as well as the tail rotors and pusher-propulsors. This capability for rapid calculation and visualization of the off-body flow field would greatly aid the designers in the placement of these components.

A previously developed algebraic transition model that regulates the magnitude of the production term in the Spalart-Allmaras one-equation turbulence model has been independently implemented in the present solver, and in the commercial CFD solver ANSYS Fluent as a user-defined function. Previous validation of this model was limited to 2-D flow over airfoils in the transitional Reynolds number regime. In the present work, this model has been also validated for large scale rotors in hover.

Committee

• Prof. Lakshmi Sankar – School of Aerospace Engineering (advisor)
• Prof. Jechiel Jagoda – School of Aerospace Engineering
• Prof. JVR Prasad – School of Aerospace Engineering
• Professor Dan Schrage – School of Aerospace Engineering
• Dr. Xiaomeng  ZHAI – Lead Software Engineer, Cadence Design Systems Inc., Burlington, MA