Ice Accretions and Icing Effects for Modern Airfoils


Book Description

Icing tests were conducted to document ice shapes formed on three different two-dimensional airfoils and to study the effects of the accreted ice on aerodynamic performance. The models tested were representative of airfoil designs in current use for each of the commercial transport, business jet, and general aviation categories of aircraft. The models were subjected to a range of icing conditions in an icing wind tunnel. The conditions were selected primarily from the Federal Aviation Administration's Federal Aviation Regulations 25 Appendix C atmospheric icing conditions. A few large droplet icing conditions were included. To verify the aerodynamic performance measurements, molds were made of selected ice shapes formed in the icing tunnel. Castings of the ice were made from the molds and placed on a model in a dry, low-turbulence wind tunnel where precision aerodynamic performance measurements were made. Documentation of all the ice shapes and the aerodynamic performance measurements made during the icing tunnel tests is included in this report. Results from the dry, low-turbulence wind tunnel tests are also presented.







Ice Cap Strains and Some Effects on Engineering Structures


Book Description

The components of strain for the upper layers of ice sheets are given in terms of ice flow velocity and snow accumulation rate. Methods of estimating the components of strain rate which are necessary for design of engineering structures are outlined, and representative measured values are given. The relation between observed structural deformation and ice cap straining is discussed. (Author).




Control-Surface Deflection Effects on the Innovative Control Effectors (ICE 101) Design


Book Description

A static wind tunnel test of the Innovative Controls Effectors (ICE 101) conceptual aircraft configuration was conducted in the Air Force Research Laboratory's Vertical Wind Tunnel. This entry characterized the increments to the aerodynamic loading provided by the various control surfaces while using a more finely-resolved test matrix in angle of attack and sideslip than typically seen in wind tunnel testing. The purpose for obtaining these data was to determine the effect which control surface deflection had on critical state locations in preparation for the test of a second ICE model built with remotely- actuated control surfaces. (Critical states are discrete flight mechanical states where the aerodynamic response looses its analytic dependence on one or more state variables.) These data demonstrate that the aerodynamic increments are in many cases at minimum nonlinear functions of the surface deflection angle, and strongly suggest that some critical states do shift in angle of attack and/or sideslip with changing deflection angle.




Women on Ice


Book Description

Methamphetamine (ice, speed, crystal, shard) has been called epidemic in the United States. Yet few communities were ready for increased use of methamphetamine by suburban women. Women on Ice is the first book to study exclusively the lives of women who use the drug and its effects on their families. In-depth interviews with women in the suburban counties of one of the largest metropolitan areas in the U.S. chronicle the details of their initiation into methamphetamine, the turning points into problematic drug use, and for a few, their escape from lives veering out of control. Their life course and drug careers are analyzed in relation to the intersecting influences of social roles, relationships, social/political structures, and political trends. Examining the effects of punitive drug policy, inadequate social services, and looming public health risks, including HIV/AIDS and hepatitis C, the book gives voice to women silenced by shame. Boeri introduces new and developing concepts in the field of addiction studies and proposes policy changes to more broadly implement initiatives that address the problems these women face. She asserts that if we are concerned that the war on drugs is a war on drug users, this book will alert us that it is also a war on suburban families.




Ice Adhesion


Book Description

This unique book presents ways to mitigate the disastrous effects of snow/ice accumulation and discusses the mechanisms of new coatings deicing technologies. The strategies currently used to combat ice accumulation problems involve chemical, mechanical or electrical approaches. These are expensive and labor intensive, and the use of chemicals raises serious environmental concerns. The availability of truly icephobic surfaces or coatings will be a big boon in preventing the devastating effects of ice accumulation. Currently, there is tremendous interest in harnessing nanotechnology in rendering surfaces icephobic or in devising icephobic surface materials and coatings, and all signals indicate that such interest will continue unabated in the future. As the key issue regarding icephobic materials or coatings is their durability, much effort is being spent in developing surface materials or coatings which can be effective over a long period. With the tremendous activity in this arena, there is strong hope that in the not too distant future, durable surface materials or coatings will come to fruition. This book contains 20 chapters by subject matter experts and is divided into three parts— Part 1: Fundamentals of Ice Formation and Characterization; Part 2: Ice Adhesion and Its Measurement; and Part 3: Methods to Mitigate Ice Adhesion. The topics covered include: factors influencing the formation, adhesion and friction of ice; ice nucleation on solid surfaces; physics of ice nucleation and growth on a surface; condensation frosting; defrosting properties of structured surfaces; relationship between surface free energy and ice adhesion to surfaces; metrology of ice adhesion; test methods for quantifying ice adhesion strength to surfaces; interlaboratory studies of ice adhesion strength; mechanisms of surface icing and deicing technologies; icephobicities of superhydrophobic surfaces; anti-icing using microstructured surfaces; icephobic surfaces: features and challenges; bio-inspired anti-icing surface materials; durability of anti-icing coatings; durability of icephobic coatings; bio-inspired icephobic coatings; protection from ice accretion on aircraft; and numerical modeling and its application to inflight icing.




Effects of Numbers, Sizes and Crystal Structures on Measurements of Ice Hydrometeors


Book Description

Simulated measurements of assumed ice hydrometeor environments generate number-size distributions similar to those from in situ measurements even to the point of reproducing several inconsistencies often found in actual data. This report describes the computer fabrication of ice hydrometeors composed of single columns and combinations of columns with random spatial orientation and the simulated measuring of those particles by PMS 1-D instruments. Varying effects on distribution shapes are demonstrated by using different assumptions of particle number and sizes. Efforts were concentrated on exploring the problems of deficient number counts in the first or first few classes of precipitation probe data, non-compatible number concentrations from the cloud and precipitation probes, and the apparent existence of a few large particles that are not consistent with the rest of the distribution. This investigation indicates that the numbers, sizes, crystalline structures, and spatial positioning of hydrometeors may be the cause of these effects.




Ice in Streams


Book Description







Air-Ice-Ocean Interaction


Book Description

At a time when the polar regions are undergoing rapid and unprecedented change, understanding exchanges of momentum, heat and salt at the ice-ocean interface is critical for realistically predicting the future state of sea ice. By offering a measurement platform largely unaffected by surface waves, drifting sea ice provides a unique laboratory for studying aspects of geophysical boundary layer flows that are extremely difficult to measure elsewhere. This book draws on both extensive observations and theoretical principles to develop a concise description of the impact of stress, rotation, and buoyancy on the turbulence scales that control exchanges between the atmosphere and underlying ocean when sea ice is present. Several interesting and unique observational data sets are used to illustrate different aspects of ice-ocean interaction ranging from the impact of salt on melting in the Greenland Sea marginal ice zone, to how nonlinearities in the equation of state for seawater affect mixing in the Weddell Sea. The book’s content, developed from a series of lectures, may be appropriate additional material for upper-level undergraduates and first-year graduate students studying the geophysics of sea ice and planetary boundary layers.