Student Name: Michelle Ku

Advisor: Dr. Lakshmi Sankar

Milestone: PhD Thesis Proposal

Degree Program: Aerospace Engineering

Title: Roughness Tolerant Airfoil Design for Rotor and Propeller Applications

Abstract: A technique for rapidly designing roughness tolerant low drag airfoils has been developed. Airfoils of varying thickness to chord ratio, ranging from 10% to 22% have been designed. A target pressure distribution is specified by the designer for a notional lift coefficient, Reynolds number, and Mach number. The specified pressure distribution is first analyzed using classical integral boundary layer analyses and empirical transition criteria for smooth and rough airfoils to ensure laminar flow over much of the airfoil under design conditions. The resulting airfoil is subsequently analyzed under natural transition, and forced transition caused by the tripping of the boundary layer due to roughness near the leading edge. It is found that the present approach performs well for a broad range of lift coefficients. An in-house propeller design and analysis tool has been used to examine the impact of the low drag airfoil on the pusher propeller performance designed for a fixed wing UAV drone configuration. The present airfoils have been found to improve hover performance of legacy rotors (e.g. rotors used on S76, UH-60A) for a broad range of thrust settings. Additional work has been proposed towards improved roughness tolerant airfoils, assessment of new airfoils for applications in drone and eVTOL propeller applications, and assessment of the new airfoils in the tip region of legacy helicopters in high speed forward flight.

Date and time: 2026-03-06, 1pm-2pm

Location: MK 317 and on Teams meeting (Microsoft Teams meeting Join: https://teams.microsoft.com/meet/2915085768745?p=4dGpogkKP01oA3qrAi Meeting ID: 291 508 576 874 5 Passcode: 2pw72mi6)

Committee:
Dr. Lakshmi Sankar (advisor), School of Aerospace Engineering
Dr. Brian German, School of Aerospace Engineering
Dr. Graeme Kennedy, School of Aerospace Engineering
Dr. Juergen Rauleder, School of Aerospace Engineering
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