Fundamentals Of Modern Unsteady Aerodynamics

In this book, the author introduces the concept of unsteady aerodynamics and its underlying principles. He provides the readers with a comprehensive review of the fundamental physics of free and forced unsteadiness, the terminology and basic equations of aerodynamics ranging from incompressible flow to hypersonics. The book also covers modern topics related to the developments made in recent years, especially in relation to wing flapping for propulsion. The book is written for graduate and senior year undergraduate students in aerodynamics and also serves as a reference for experienced researchers. Each chapter includes ample examples, questions, problems and relevant references. The treatment of these modern topics has been completely revised end expanded for the new edition. It now includes new numerical examples, a section on the ground effect, and state-space representation.

In this textbook, the author introduces the concept of unsteady aerodynamics and its underlying principles. He provides the readers with a full review of fundamental physics of the free and the forced unsteadines, the terminology and basic equations of aerodynamics ranging from incompressible flow to hypersonics. The book also covers the modern topics concerning the developments made during the last years, especially in relation to wing flappings for propulsion. The book is written for graduate and senior year undergraduate students in Aerodynamics, and it serves as a reference for experienced researchers. Each chapter includes ample examples, questions, problems and relevant references.

Unsteady Aerodynamics A comprehensive overview of unsteady aerodynamics and its applications The study of unsteady aerodynamics goes back a century and has only become more significant as aircraft become increasingly sophisticated, fly faster, and their structures are lighter and more flexible. Progress in the understanding of flow physics, computing power and techniques, and modelling technologies has led to corresponding progress in unsteady aerodynamics, with a wide range of methods currently used to predict the performance of engineering structures under unsteady conditions. Unsteady Aerodynamics offers a comprehensive and systematic overview of the application of potential and vortex methods to the subject. Beginning with an introduction to the fundamentals of unsteady flow, it then discusses the modelling of attached and separated, incompressible and compressible flows around two-dimensional and three-dimensional bodies. The result is an essential resource for design and simulation in aerospace engineering. Unsteady Aerodynamics readers will also find: MATLAB examples and exercises throughout, with codes and solutions on an accompanying website Detailed discussion of most classes of unsteady phenomena, including flapping flight, transonic flow, dynamic stall, flow around bluff bodies and more Validation of theoretical and numerical predictions using comparisons to experimental data from the literature Unsteady Aerodynamics is ideal for researchers, engineers, and advanced students in aerospace engineering.

Aeroelasticity is an essential discipline for the design of airplanes, unmanned systems, and innovative configurations. This book introduces the subject of unsteady aerodynamics and dynamic aeroelasticity by presenting industry-standard techniques, such as the Doublet Lattice Method for nonplanar wing systems. “Introduction to Unsteady Aerodynamics and Dynamic Aeroelasticity'' is a useful reference for aerospace engineers and users of NASTRAN and ZAERO but is also an excellent complementary textbook for senior undergraduate and graduate students. The theoretical material includes: · Fundamental equations of aerodynamics. · Concepts of Velocity and Acceleration Potentials. · Theory of small perturbations. · Virtual displacements and work, Hamilton's Principle, and Lagrange's Equations. · Aeroelastic equations expressed in the time, Laplace, and Fourier domains. · Concept of Generalized Aerodynamic Force Matrix. · Complete derivation of the nonplanar kernel for unsteady aerodynamic analyses. · Detailed derivation of the Doublet Lattice Method. · Linear Time-Invariant systems and stability analysis. · Rational function approximation for the generalized aerodynamic force matrix. · Fluid-structure boundary conditions and splining. · Root locus technique. · Techniques to find the flutter point: k, k-E, p-k, non-iterative p-k, g, second-order g, GAAM, p, p-L, p-p, and CV methods.

This book opens with a discussion of the vorticity-dynamic formulation of the low Mach number viscous flow problem. It examines the physical aspects of the velocity and the vorticity fields, their instantaneous relationship, and the transport of vorticity in viscous fluids for steady and unsteady flows. Subsequently, using classical analyses it explores the mathematical aspects of vorticity dynamics and issues of initial and boundary conditions for the viscous flow problem. It also includes the evolution of the vorticity field which surrounds and trails behind airfoils and wings, generalizations of Helmholtz’ vortex theorems and the Biot-Savart Law. The book introduces a theorem that relates the aerodynamic force to the vorticity moment and reviews the applications of the theorem. Further, it presents interpretations of the Kutta-Joukowski theorem and Prandtl’s lifting line theory for vorticity dynamics and discusses wake integral methods. The virtual-mass effect is shown to be the seminal event in unsteady aerodynamics and a simple approach for evaluating virtual-mass forces on the basis of vorticity dynamics is presented. The book presents a modern viewpoint on vorticity dynamics as the framework for understanding and establishing the fundamental principles of viscous and unsteady aerodynamics. It is intended for graduate-level students of classical aerodynamics and researchers exploring the frontiers of fully unsteady and non-streamlined aerodynamics.

Aeroelasticity is the study of flexible structures situated in a flowing fluid. Its modern origins are in the field of aerospace engineering, but it has now expanded to include phenomena arising in other fields such as bioengineering, civil engineering, mechanical engineering and nuclear engineering. The present volume is a teaching text for a first, and possibly second, course in aeroelasticity. It will also be useful as a reference source on the fundamentals of the subject for practitioners. In this third edition, several chapters have been revised and three new chapters added. The latter include a brief introduction to `Experimental Aeroelasticity', an overview of a frontier of research `Nonlinear Aeroelasticity', and the first connected, authoritative account of `Aeroelastic Control' in book form. The authors are drawn from a range of fields including aerospace engineering, civil engineering, mechanical engineering, rotorcraft and turbomachinery. Each author is a leading expert in the subject of his chapter and has many years of experience in consulting, research and teaching.

Currently, the use of computational fluid dynamics (CFD) solutions is considered as the state-of-the-art in the modeling of unsteady nonlinear flow physics and offers an early and improved understanding of air vehicle aerodynamics and stability and control characteristics. This Special Issue covers recent computational efforts on simulation of aerospace vehicles including fighter aircraft, rotorcraft, propeller driven vehicles, unmanned vehicle, projectiles, and air drop configurations. The complex flow physics of these configurations pose significant challenges in CFD modeling. Some of these challenges include prediction of vortical flows and shock waves, rapid maneuvering aircraft with fast moving control surfaces, and interactions between propellers and wing, fluid and structure, boundary layer and shock waves. Additional topic of interest in this Special Issue is the use of CFD tools in aircraft design and flight mechanics. The problem with these applications is the computational cost involved, particularly if this is viewed as a brute-force calculation of vehicle’s aerodynamics through its flight envelope. To make progress in routinely using of CFD in aircraft design, methods based on sampling, model updating and system identification should be considered.