Heaving Inverted Wing in Extreme Ground Effect

Abstract

An inverted single element was subjected to a sinusoidal heaving motion in both free flight and extreme ground effect, with the ground-effect simulations oscillating in various states of interaction with the peak lift ride height of the wing. Peak negative lift during the heaving cycle was greater than the static values at the same ground clearances, time, and ensemble averaging showed an overall reduction in the lift coefficient of 10–22%. An analytical model combining potential flow lift predictions and a new variation of the Goman–Khrabrov state-space model predicts the lift behavior of the wing-in-ground effect based on reduced frequency and ground clearance.