Fundamentals of Producing Lift Forces

This book provides a detailed quantitative analysis of the physical phenomena related to various levitation or lift forces, being centered around magnetic levitation that is discussed in the final chapter. It covers a wide range of phenomena, from ships and aircrafts to ultrasonic and magnetic levitation, providing basic discussions with fundamental formulations. Updating an overview of the levitation/lift technologies could lead to another breakthrough for future vehicles and equipment. There are a variety of situations for floating, lifting, or levitating. Objects are suspended in water, air, sound-induced pressure fluctuations, optical beams, or electromagnetic forces. Some objects are made to float for processing in factories, balloons move through the air, ships and hovercrafts cruise on the water, drones, fixed-wing aircrafts, helicopters come and go in the sky, and magnetically levitated vehicles transport passengers at very high speeds with no sound other than the air rushing past it. The chapter of lifting by fixed wings clarifies the debate about the lift force mechanism of fixed-wing aircraft, which is still misunderstood even in some articles. Drones are now being applied in a variety of fields, and the chapter of rotating wings provides a detailed discussion of their dynamics. Ultrasonic levitation is a unique technique that levitates small objects or relatively heavy planar objects without using a container. The associated chapter introduces analytical methods and demonstrates its usefulness through numerical examples. Detailed and advanced discussions are given for electromagnetic levitation, beginning with determining the controller gains from a physical perspective to construct an electromagnetic levitation system. Regarding the electrodynamic levitation system, which is suitable for super-high-speed transportation, this book shows analytical approaches in detail to solve the advanced problems for eddy currents and electromagnetic forces. The detailed analysis of the electrodynamic levitation system results in some novel findings: the quantitative differences in levitation/drag ratios for various electrodynamic levitation configurations. The novel analytical approach is also given to the electromagnetic field produced by the Halbach array permanent magnets, which is applied to a small-scale electrodynamic levitation vehicle instead of using high-cost superconducting magnets.