A Critical Review of the Measurement of Ice Adhesion to Solid Substrates

Ice adhesion is an issue spanning a wide range of technical fields. In the aerospace industry, ice accretion has led to a large number of casualties and costs the industry billions of dollars every year. To design effective anti-/de-icing systems, the adhesion of ice to surfaces must be understood. In this review paper, the authors surveyed for papers providing methods for the measurement of ice adhesion. 113 papers were identified for comparison, with data being extracted from 58 papers with common test surfaces (aluminum, steel, Teflon (Chemours), and polyurethane). The methods used were categorized and data were compared based on their precision and the trends they demonstrated. Conceptual problems were identified with the tests used in the literature and discussed, and open questions relevant to testing the adhesion of ice were identified. Several key parameters affecting ice adhesion identified from the literature were temperature, surface roughness, strain rate, and impact velocity. Their effects on adhesion strength were discussed. While researching this topic, it was discovered that many papers did not report the strain rate in their tests, and the vast majority of papers did not correct their data for stress concentrations on the surface, either of which has been shown to cause variation in the data by one order of magnitude. Data compared from the literature typically spanned one to three orders of magnitude. The causes of these variations were discussed

Laminar-Turbulent Transition of a Low Reynolds Number Rigid or Flexible Airfoil

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76325/1/AIAA-25812-306.pd

Aerodynamics of Low Reynolds Number Plunging Airfoil Under Gusty Environment

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77398/1/AIAA-2007-71-738.pd

Reliability-Based Design Optimization of a Transonic Compressor

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77181/1/AIAA-16262-571.pd

Comparative Study of Pitch-Plunge Airfoil Aerodynamics at Transitional Reynolds Number

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76128/1/AIAA-2008-652-591.pd

Experimental Study of the Dynamics of Water Film on an Aluminum Substrate under Wind Shear

This document is the Accepted Manuscript version of a paper presented at the 9th AIAA Atmospheric and Space Environments Conference, 5-9 June 2017, Denver, Colorado. Content in the UH Research Archive is made available for personal research, educational, and non-commercial purposes only. Unless otherwise stated, all content is protected by copyright, and in the absence of an open license, permissions for further re-use should be sought from the publisher, the author, or other copyright holder.Aircraft icing poses a serious threat to flight safety. Unfrozen parts of impinging water on the surface of the aircraft will run back under the effect of high-speed airflow, altering liquid distribution and heat transfer characteristics. In this paper we conducted a series of experiments over a wide range of wind speed (Ua = 17.8~52.2 m/s), film Reynolds number (Ref = 26~128) and inclined angle (α = 0°, ±30°, ±45°) to investigate the dynamics of thin water film on an Aluminum substrate. The superficial morphology of the water film were investigated by high-speed camera, and the instantaneous film thicknesses were measured by a laser focus displacement meter based on a confocal chromatic technique. The interface between the gas and liquid phases consisted of underlying thin film and multiple scaled fluctuations. The measured time-averaged filim thickness data agrees with previous model predictions. Based on the experimental results, a relationship between the film thickness and the wind speed, film Reynolds number, inclined angle was proposed. A new correlation to calculate the interfacial shear stress and superficial roughness on the wavy surface is also suggested

Aerostructural Optimization of a Transonic Compressor Rotor

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77121/1/AIAA-15397-760.pd

Multi-Objective Optimization of Transonic Compressor Blade Using Evolutionary Algorithm

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77106/1/AIAA-14667-294.pd

Computational Aerodynamics of Low Reynolds Number Plunging, Pitching and Flexible Wings for MAV Applications

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76136/1/AIAA-2008-523-190.pd

Ultrafast Photoinduced Band Splitting and Carrier Dynamics in Chiral Tellurium Nanosheets

Trigonal tellurium (Te) is a chiral semiconductor that lacks both mirror and inversion symmetries, resulting in complex band structures with Weyl crossings and unique spin textures. Detailed time-resolved polarized reflectance spectroscopy is used to investigate its band structure and carrier dynamics. The polarized transient spectra reveal optical transitions between the uppermost spin-split H4 and H5 and the degenerate H6 valence bands (VB) and the lowest degenerate H6 conduction band (CB) as well as a higher energy transition at the L-point. Surprisingly, the degeneracy of the H6 CB (a proposed Weyl node) is lifted and the spin-split VB gap is reduced upon photoexcitation before relaxing to equilibrium as the carriers decay. Using ab initio density functional theory (DFT) calculations we conclude that the dynamic band structure is caused by a photoinduced shear strain in the Te film that breaks the screw symmetry of the crystal. The band-edge anisotropy is also reflected in the hot carrier decay rate, which is a factor of two slower along c-axis than perpendicular to it. The majority of photoexcited carriers near the band-edge are seen to recombine within 30 ps while higher lying transitions observed near 1.2 eV appear to have substantially longer lifetimes, potentially due to contributions of intervalley processes in the recombination rate. These new findings shed light on the strong correlation between photoinduced carriers and electronic structure in anisotropic crystals, which opens a potential pathway for designing novel Te-based devices that take advantage of the topological structures as well as strong spin-related properties.Comment: 42 pages, 13 figure