Aerodynamic interaction between propellers and wings

Abstract

A combined experimental and computational investigation of the aerodynamic interaction between propellers and wings has been conducted at the Purdue University Aerospace Sciences Laboratory. This study's primary objective was the determination of the time averaged performance of a propeller and wing in a tractor configuration. A wind tunnel test was performed using an untapered, semispan wing and a Purdue Model propeller mounted in a tractor arrangement, All tests were conducted at low subsonic speeds, M = 0.1, and a Reynolds Number of 470,000 based on the wing chord of 8 inches. Wing angle of attack was varied from 0 to +13 degrees and prop advance ratio ranged frcm 2.4 (windmill) to 1.1 (maximum power).A computational analysis utilizing two individual methods was performed. A semi-empirical model which calculated wing performance for a predetermined steady -prop wake velocity distribution was formulated.The second method was a vortex lattice simulation of both the propeller and wing. Since the propeller and wing circulation distributions are solved simultaneously in this method, calculation of quasi-steady loading is possible.The results of the experiment and the computational analysis showed good agreement and indicated a significant steady state performance improvement for the tractor configuration, including a reduction in wing induced drag and increases in propeller efficiency and wing lift curve slope. The quasi-steady results of the computational analysis provided insight into the time dependent loadings on both the propeller and wing.

A Surrogate-Based Multi-Disciplinary Design Optimization Framework Exploiting Wing-Propeller Interaction

“…The physical ground for such effect is schematically represented by figures 1.2 and 1.3 by Witkowski [2], and can be explained as follows. [2] It is commonly known how wing induced drag can be seen as the result of a backward tilting of the lift vector, due to a decrease in local angle of attack induced by the wing down-wash.…”

“…The physical ground for such effect is schematically represented by figures 1.2 and 1.3 by Witkowski [2], and can be explained as follows. [2] It is commonly known how wing induced drag can be seen as the result of a backward tilting of the lift vector, due to a decrease in local angle of attack induced by the wing down-wash. Following the same rationale, it is easy to grasp how the increased local angle of attack at the wing region blown by the propeller up-wash will entail a forward tilting of the lift vector, while the opposite will occur at the down-wash side.…”

“…INTRODUCTION reduction in induced drag, which may as well be seen as a side effect of the wing capability of reducing the swirl imparted by the propeller to the flow, thus recovering part of the otherwise wasted rotational kinetic energy. Many authors, among which Kroo [9], Miranda & Brennan [10], Witkowski [2] and Veldhuis [16] have proven either theoretically or experimentally that a proper integration between propeller slipstream and wing yields a reduction in induced drag.…”

“…Witkoswki [2] developed a quasi steady full interaction analysis, modeling both wing and propeller with VLM, along with a fixed wake analysis. Strip theory based on experimental 2D airfoil data was adopted as well in his work to evaluate viscous drag.…”

Unsteady Numerical Simulation of the Mutual Disturbance between Propeller and Wing

“…Such mechanism has seen its application in the design of contrarotating propellers and ducted propellers with stators. 20) However, wing rectifying will definitely bring about change in the aerodynamic performance of the wing, as discussed before. Secondly, in the rear-mounted configuration, the propeller is subjected to the low-speed wake flow of the wing, resulting in changing the working condition of the propeller.…”