Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Engineering
Lifting-Line Predictions For Induced Drag And Lift In Ground Effect, W. F. Phillips, Doug F. Hunsaker
Lifting-Line Predictions For Induced Drag And Lift In Ground Effect, W. F. Phillips, Doug F. Hunsaker
Mechanical and Aerospace Engineering Faculty Publications
Closed-form relations are presented for estimating ratios of the induced-drag and lift coefficients acting on a wing in ground effect to those acting on the same wing outside the influence of ground effect. The closed-form relations for these ground-effect influence ratios were developed by correlating results obtained from numerical solutions to Prandtl's lifting-line theory. Results show that these influence ratios are not unique functions of the ratio of wing height to wingspan, as is sometimes suggested in the literature. These ground-effect influence ratios also depend on the wing planform, aspect ratio, and lift coefficient.
Decomposed Lifting-Line Predictions And Optimization For Propulsive Efficiency Of Flapping Wings, W. F. Phillips, R. A. Miller, Doug F. Hunsaker
Decomposed Lifting-Line Predictions And Optimization For Propulsive Efficiency Of Flapping Wings, W. F. Phillips, R. A. Miller, Doug F. Hunsaker
Mechanical and Aerospace Engineering Faculty Publications
A decomposed Fourier series solution to Prandtl's classical lifting-line theory is used to predict the lift, induced-thrust, and power coefficients developed by a flapping wing. A significant advantage of this quasi-steady analytical solution over commonly used numerical methods is the utility provided for optimizing wing flapping cycles. The analytical solution involves five time-dependent functions that could all be optimized to maximize thrust, propulsive efficiency, and/or other performance measures. Results show that by optimizing only two of these five functions, propulsive efficiencies exceeding 97% can be obtained. Results are presented for untwisted rectangular wings in pure plunging, rectangular wings with linear …