Transonic Shock And Multidimensional Flows

Mathematics Research Center Symposium: Transonic, Shock, and Multidimensional Flows: Advances in Scientific Computing covers the lectures presented at a Symposium on Transonic, Shock, and Multidimensional Flows, held in Madison on May 13-15, 1981, under the auspices of the Mathematics Research Center of the University of Wisconsin. The book focuses on the advancements in the scientific computation of high-speed aerodynamic phenomena and related fluid motions. The selection first elaborates on computational fluid dynamics of airfoils and wings; shock-free configurations in two- and three-dimensional transonic flow; and steady-state solution of the Euler equations for transonic flow. Discussions focus on boundary conditions, convergence acceleration, indirect design of airfoils, and trailing edge and the boundary layer. The text then examines the calculation of transonic potential flow past three-dimensional configurations and remarks on the numerical solution of Tricomi-type equations. The manuscript ponders on the design and numerical analysis of vortex methods, shock calculations and the numerical solution of singular perturbation problems, tracking of interfaces for fluid flow, and transonic flows with viscous effects. Topics include numerical algorithm, difference approximation for scalar equations, boundary conditions, transonic flow in a tube, and governing equations. The selection is a dependable reference for researchers interested in transonic, shock, and multidimensional flows.

The author's approach is one of continuum models of the aerodynamic flow interacting with a flexible structure whose behavior is governed by partial differential equations. Both linear and nonlinear models are considered although much of the book is concerned with the former while keeping the latter clearly in view. A complete chapter is also devoted to nonlinear theory. The author has provided new insights into the classical inviscid aerodynamics and raises novel and interesting questions on fundamental issues that have too often been neglected or forgotten in the development of the early history of the subject. The author contrasts his approach with discrete models for the unsteady aerodynamic flow and the finite element model for the structure. Much of the aeroelasticity has been developed with applications formerly in mind because of its enormous consequences for the safety of aircraft. Aeroelastic instabilities such as divergence and flutter and aeroelastic responses to gusts can pose a significant hazard to the aircraft and impact its performance. Yet, it is now recognized that there are many other physical phenomena that have similar characteristics ranging from flows around flexible tall buildings and long span bridges, alternate energy sources such as electric power generation by smart structures to flows internal to the human body. From the foreword: "For the theorist and applied mathematician who wishes an introduction to this fascinating subject as well as for the experienced aeroelastician who is open to new challenges and a fresh viewpoint, this book and its author have much to offer the reader." Earl Dowell, Duke University, USA

This book is aimed to make careful analysis to various mathematical problems derived from shock reflection by using the theory of partial differential equations. The occurrence, propagation and reflection of shock waves are important phenomena in fluid dynamics. Comparing the plenty of studies of physical experiments and numerical simulations on this subject, this book makes main efforts to develop the related theory of mathematical analysis, which is rather incomplete so far. The book first introduces some basic knowledge on the system of compressible flow and shock waves, then presents the concept of shock polar and its properties, particularly the properties of the shock polar for potential flow equation, which are first systematically presented and proved in this book. Mathematical analysis of regular reflection and Mach reflection in steady and unsteady flow are the most essential parts of this book. To give challenges in future research, some long-standing open problems are listed in the end. This book is attractive to researchers in the fields of partial differential equations, system of conservation laws, fluid dynamics, and shock theory.

This book offers a survey of recent developments in the analysis of shock reflection-diffraction, a detailed presentation of original mathematical proofs of von Neumann's conjectures for potential flow, and a collection of related results and new techniques in the analysis of partial differential equations (PDEs), as well as a set of fundamental open problems for further development. Shock waves are fundamental in nature. They are governed by the Euler equations or their variants, generally in the form of nonlinear conservation laws—PDEs of divergence form. When a shock hits an obstacle, shock reflection-diffraction configurations take shape. To understand the fundamental issues involved, such as the structure and transition criteria of different configuration patterns, it is essential to establish the global existence, regularity, and structural stability of shock reflection-diffraction solutions. This involves dealing with several core difficulties in the analysis of nonlinear PDEs—mixed type, free boundaries, and corner singularities—that also arise in fundamental problems in diverse areas such as continuum mechanics, differential geometry, mathematical physics, and materials science. Presenting recently developed approaches and techniques, which will be useful for solving problems with similar difficulties, this book opens up new research opportunities.

From the preface: Fluid dynamics is an excellent example of how recent advances in computational tools and techniques permit the rapid advance of basic and applied science. The development of computational fluid dynamics (CFD) has opened new areas of research and has significantly supplemented information available from experimental measurements. Scientific computing is directly responsible for such recent developments as the secondary instability theory of transition to turbulence, dynamical systems analyses of routes to chaos, ideas on the geometry of turbulence, direct simulations of turbulence, three-dimensional full-aircraft flow analyses, and so on. We believe that CFD has already achieved a status in the tool-kit of fluid mechanicians equal to that of the classical scientific techniques of mathematical analysis and laboratory experiment.

Numerical methods are indispensable tools in the analysis of complex fluid flows. This book focuses on computational techniques for high-speed gas flows, especially gas flows containing shocks and other steep gradients. The book decomposes complicated numerical methods into simple modular parts, showing how each part fits and how each method relates to or differs from others. The text begins with a review of gasdynamics and computational techniques. Next come basic principles of computational gasdynamics. The last two parts cover basic techniques and advanced techniques. Senior and graduate level students, especially in aerospace engineering, as well as researchers and practising engineers, will find a wealth of invaluable information on high-speed gas flows in this text.

This volume contains revised and edited forms of papers presented at the Symposium on Numerical and Physical Aspects of Aerodynamic Flows, held at the California State University from 19 to 21 January 1981. The Symposium was organized to bring together leading research workers in those aspects of aerodynamic flows represented by the five parts and to fulfill the following purposes : first, to allow the presentation of technical papers which provide a basis for research workers to assess the present status of the subject and to formulate priorities for the future; and second, to promote informal discussion and thereby to assist the communication and develop ment of novel concepts. The format ofthe content ofthe volume is similar to that ofthe Symposium and addresses, in separate parts: Numerical Fluid Dynamics, Interactive Steady Boundary Layers, Singularities in Unsteady Boundary Layers, Transonic Flows, and Experimental Fluid Dynamics. The motivation for most of the work described relates to the internal and extern al aerodynamics of aircraft and to the development and appraisal of design methods based on numerical solutions to conservation equations in differential forms, for corresponding components. The chapters concerned with numerical fluid dynamics can, perhaps, be interpreted in a more general context, but the emphasis on boundary-Iayer flows and the special consideration oftransonic flows reflects the interest in external flows and the recent advances which have allowed the calculation methods to encompass transonic regions.