Methods for Obtaining Desired Helicopter Stability Characteristics and Procedures for Stability Predictions


Book Description

Part 1 of this report presents a brief review of methods available to the helicopter designer for obtaining desired stability characteristics by modifications to the airframe design. The discussion is based on modifications made during the establishment of flying-qualities criteria and includes sample results of theoretical studies of additional methods. The conclusion is reached that it is now feasible to utilize combinations of methods whereby stability-parameter values are realized which in turn provide the desired stability characteristics. Part 2 reviews some of the methods of predicting rotor stability derivatives. The procedures by which these rotor derivatives are employed to estimate helicopter stability characteristics have been summarized.










Twenty-Second Symposium on Naval Hydrodynamics


Book Description

The Twenty-Second Symposium on Naval Hydrodynamics was held in Washington, D.C., from August 9-14, 1998. It coincided with the 100th anniversary of the David Taylor Model Basin. This international symposium was organized jointly by the Office of Naval Research (Mechanics and Energy Conversion S&T Division), the National Research Council (Naval Studies Board), and the Naval Surface Warfare Center, Carderock Division (David Taylor Model Basin). This biennial symposium promotes the technical exchange of naval research developments of common interest to all the countries of the world. The forum encourages both formal and informal discussion of the presented papers, and the occasion provides an opportunity for direct communication between international peers.




NASA SP.


Book Description




Low-Speed Wind Tunnel Testing


Book Description

A brand-new edition of the classic guide on low-speed wind tunnel testing While great advances in theoretical and computational methods have been made in recent years, low-speed wind tunnel testing remains essential for obtaining the full range of data needed to guide detailed design decisions for many practical engineering problems. This long-awaited Third Edition of William H. Rae, Jr.'s landmark reference brings together essential information on all aspects of low-speed wind tunnel design, analysis, testing, and instrumentation in one easy-to-use resource. Written by authors who are among the most respected wind tunnel engineers in the world, this edition has been updated to address current topics and applications, and includes coverage of digital electronics, new instrumentation, video and photographic methods, pressure-sensitive paint, and liquid crystal-based measurement methods. The book is organized for quick access to topics of interest, and examines basic test techniques and objectives of modeling and testing aircraft designs in low-speed wind tunnels, as well as applications to fluid motion analysis, automobiles, marine vessels, buildings, bridges, and other structures subject to wind loading. Supplemented with real-world examples throughout, Low-Speed Wind Tunnel Testing, Third Edition is an indispensable resource for aerospace engineering students and professionals, engineers and researchers in the automotive industries, wind tunnel designers, architects, and others who need to get the most from low-speed wind tunnel technology and experiments in their work.




Three-Dimensional Flow in the Root Region of Wind Turbine Rotors


Book Description

This book presents the state of the art in the analyses of three-dimensional flow over rotating wind turbine blades. Systematic studies for wind turbine rotors with different sizes were carried out numerically employing three different simulation approaches, namely the Euler, URANS and DDES methods. The main mechanisms of the lift augmentation in the blade inboard region are described in detail. The physical relations between the inviscid and viscous effects are presented and evaluated, emphasizing the influence of the flow curvature on the resulting pressure distributions. Detailed studies concerning the lift augmentation for large wind turbine rotors are considered as thick inboard airfoils characterized by massive separation are desired to stronger contribute to power production. Special attention is given to the analyses of wind turbine loads and flow field that can be helpful for the interpretation of the occurring physical phenomena. The book is aimed at students, researchers, engineers and physicists dealing with wind engineering problems, but also for a wider audience involved in flow computations.