Author:
Quinn Daniel B.,Moored Keith W.,Dewey Peter A.,Smits Alexander J.
Abstract
AbstractExperimental and computational results are presented on an aerofoil undergoing pitch oscillations in ground effect, that is, close to a solid boundary. The time-averaged thrust is found to increase monotonically as the mean position of the aerofoil approaches the boundary while the propulsive efficiency stays relatively constant, showing that ground effect can enhance thrust at little extra cost for a pitching aerofoil. Vortices shed into the wake form pairs rather than vortex streets, so that in the mean a momentum jet is formed that angles away from the boundary. The time-averaged lift production is found to have two distinct regimes. When the pitching aerofoil is between 0.4 and 1 chord lengths from the ground, the lift force pulls the aerofoil towards the ground. In contrast, for wall proximities between 0.25 and 0.4 chord lengths, the lift force pushes the aerofoil away from the ground. Between these two regimes there is a stable equilibrium point where the time-averaged lift is zero and thrust is enhanced by approximately 40 %.
Publisher
Cambridge University Press (CUP)
Subject
Mechanical Engineering,Mechanics of Materials,Condensed Matter Physics
Reference33 articles.
1. Rajiform locomotion: three-dimensional kinematics of the pectoral fin surface during swimming by freshwater stingray Potamotrygon orbignyi
2. The effect of solid and porous channel walls on steady swimming of stealhead trout, Oncorhynchus mykiss;Webb;J. Expl Biol.,1993
3. Numerical Simulation of a Flapping Foil with Chordwise or Spanwise Flexibility
4. The significance of ground effect to the aerodynamic cost of flight and energetics of the black skimmer (Rhyncops nigra);Withers;J. Expl Biol.,1977
5. Asymptotic theory of an oscillating wing section in weak ground effect
Cited by
114 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献