Aerodynamics of a Lifting System in Extreme Ground Effect

Alexeyev, who was the first in the world to develop the largest ground effect machine - Ekranoplan. The term extreme ground effect, widely used through­ out the book, is associated with very small relative ground clearances of the order of 10% or less. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . This book describes a mathematical model of flow past a lifting system performing steady and unsteady motion in close proximity to the underlying solid surface (ground). The author considers various approximations based on the general method of matched asymptotic expansions applied to lifting flows. Particular importance is attached to the case of extreme ground effects describing very small relative ground clearances. Practitioners involved in the design of wing-in-ground effect vehicles will find in this book all the relevant formulae and calculated data for the prediction of aerodynamic characteristics in this important limiting case. More generally, this book is suitable for graduate students, researchers and engineers working or lecturing in the area of theoretical aerodynamics. This book is dedicated to the memory of a distinguished Russian engineer, Rostislav E. Alexeyev, who was the first in the world to develop the largest ground effect machine - Ekranoplan. One of Alexeyev's design concepts with the aerodynamic configuration of a jlying wing can be seen on the front page. The book presents a description of a mathematical model of flow past a lifting system, performing steady and unsteady motions in close proximity to the underlying solid surface (ground). This case is interesting for practical purposes because both the aerodynamic and the economic efficiency of the system near the ground are most pronounced. Use of the method of matched asymptotic expansions enables closed form solutions for the aerodynamic characteristics of the wings-in-ground effect. These can be used for design, identification, and processing of experimental data in the course of developing ground effect vehicles. The term extreme ground effect, widely used through­ out the book, is associated with very small relative ground clearances of the order of 10% or less. The theory of a lifting surface, moving in immediate proximity to the ground, represents one of the few limiting cases that can be treated analytically. The author would like to acknowledge that this work has been influenced by the ideas of Professor Sheila E. Widnall, who was the first to apply the matched asymptotics techniques to treat lifting flows with the ground effect. Saint Petersburg, Russia February 2000 Kirill V. Rozhdestvensky Contents 1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .