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Technical Paper

Surface Contamination Effects on CRM Wing Section Model

2019-06-10
2019-01-1976
The aerodynamic effects of Cold Soaked Fuel Frost have become increasingly significant as aircraft manufacturers have applied for to allow it during aircraft take-off. The Federal Aviation Administration and the Finnish Transport Safety Agency signed a Research Agreement in aircraft icing research in 2015 and started a research co-operation in frost formation studies, computational fluid dynamics for ground de/anti-icing fluids, and de/anti-icing fluids aerodynamic characteristics. The main effort has been so far on the formation and effects of CSFF. To investigate the effects a HL-CRM wing wind tunnel model, representing the wing of a modern jet aircraft, was built including a wing tank cooling system. Real frost was generated on the wing in a wind tunnel test section and the frost thickness was measured with an Elcometer gauge. Frost surface geometry was measured with laser scanning and photogrammetry.
Technical Paper

The North Dakota Citation Research Aircraft Measurement Platform

2019-06-10
2019-01-1990
The North Dakota Citation Research Aircraft is a Cessna Citation II twin-engine fan-jet aircraft modified to be an atmospheric research platform that has been used on many field projects since the 1970s. The typical sampling speed of the modified Citation II is 160 knots indicated air speed (IAS), with sampling at altitudes up to 12.1 km (40,000 ft). The Citation Research Aircraft was operated by the University of North Dakota (UND) for many years but is now operated by Weather Modification International (WMI) of Fargo, North Dakota. WMI and UND together provide a unique test facility that is capable of deploying a wide range of instrumentation. WMI has the experience to install the custom instrumentation required for a specific field project and the expertise to conduct the most demanding aircraft sampling, including thunderstorm in-situ measurements.
Technical Paper

An Explorative Study to Use Super-Hydrophilic/Super-Hydrophobic Hybrid Surfaces for Aircraft Icing Mitigation

2019-06-10
2019-01-1995
An explorative study was performed to demonstrate the feasibility of using a novel hybrid anti-/de-icing strategy for aircraft icing mitigation. The hybrid method was developed by combining the electro-thermal heating mechanism and specialized surfaces/coatings with different wettabilities. While an electrical film heater was utilized to provide thermal energy around the leading edge of a NACA0012 airfoil model, two different coating strategies, (i.e., (a). Superhydrophobic coating covering the entire airfoil surface to increase droplets bounce-off and accelerate surface water runback vs. (b). super-hydrophilic coating at the leading edge to increase evaporation area + superhydrophobic coating in downstream to prevent runback refreezing) were proposed and evaluated aiming at maximizing the anti-/de-icing efficiency of the hybrid method.
Technical Paper

Aerodynamic Comparison of Freezing Rain and Freezing Drizzle Conditions at the RTA Icing Wind Tunnel

2019-06-10
2019-01-2023
The simulation of icing conditions in icing wind tunnels (IWTs) is a significant element in the certification of aircraft components and offers unique possibilities for research purposes. Up to 2014 only the conditions defined in Appendix C of the EASA Certification Specification 25, respectively the FAA Code of Federal Regulations Title 14 Part 25 were used for the certification processes in IWTs. In addition, Appendix O was introduced in 2014 to cover the supercooled large droplet (SLD) icing conditions of freezing drizzle and freezing rain, which pose a potential risk for flight safety. The simulation of SLD icing in IWTs is, due to the different behavior of the large droplets, very challenging and not all required conditions have successfully been recreated yet. RTA Rail Tec Arsenal Fahrzeugversuchsanlage GmbH has focused on the simulation of in-flight icing conditions since 2012 and increased effort was put in the simulation of SLDs in recent years.
Technical Paper

Extension of a 2D Algorithm for Catch Efficiency Calculation to Three Dimensions

2019-06-10
2019-01-2013
Accurate calculation of the catch efficiency β is of paramount importance for any ice accretion calculation since β is the most important factor in determining the mass of ice accretion. A new scheme has been proposed recently in [1] for accurately calculating β on a discretized two-dimensional geometry based on the results of a Lagrangian droplet trajectory integrator (start and impact conditions). This paper proposes an extension to the algorithm in Ref. [1], which is applicable to three-dimensional surfaces with arbitrary surface discretization. The 3D algorithm maintains the positive attributes of the original 2D algorithm, namely mass conservation of the impinging water, capability to deal with overlapping impingement regions and with crossing trajectories, computational efficiency of the algorithm, and low number of trajectories required to reach good accuracy in catch efficiency.
Technical Paper

Summary of the High Ice Water Content (HIWC) RADAR Flight Campaigns

2019-06-10
2019-01-2027
NASA and the FAA conducted two flight campaigns to quantify onboard weather radar measurements with in-situ measurements of high concentrations of ice crystals found in deep convective storms. The ultimate goal of this research was to improve the understanding of high ice water content (HIWC) and develop onboard weather radar processing techniques to detect regions of HIWC ahead of an aircraft to enable tactical avoidance of the potentially hazardous conditions. Both HIWC RADAR campaigns utilized the NASA DC-8 Airborne Science Laboratory equipped with a Honeywell RDR-4000 weather radar and in-situ microphysical instruments to characterize the ice crystal clouds. The purpose of this paper is to summarize how these campaigns were conducted and highlight key results. The first campaign was conducted in August 2015 with a base of operations in Ft. Lauderdale, Florida.
Technical Paper

An Experimental Study on a Hot-Air-Based Anti-/De-Icing System for the Icing Protection of Aero-Engine Inlet Guide Vanes

2019-06-10
2019-01-2039
In the present study, an experimental investigation was conducted to characterize a hot-air-based anti-/de-icing system for the icing protection of aero-engine inlet guide vanes(IGVs). The experimental study was conducted in a unique icing research tunnel available at Iowa State University (i.e., ISU-IRT). A hollowed IGV model embedded with U-shaped hot-air flowing conduit was designed and manufactured for the experimental investigations. During the experiments, while a high-speed imaging system was used to record the dynamic ice accretion or anti-/de-icing process over the surface of the IGV model for the test cases without and with the hot-air supply system being turned on, the corresponding surface temperature distributions on the IGV model were measured quantitatively by using a row of embedded thermocouples.
Technical Paper

The Influence of SLD Drop Size Distributions on Ice Accretion in the NASA Icing Research Tunnel

2019-06-10
2019-01-2022
An ice shape database has been created to document ice accretions on a 21-inch chord NACA0012 model and a 72-inch chord NACA 23012 airfoil model resulting from an exposure to a Supercooled Large Drop (SLD) icing cloud with a bimodal drop size distribution. The ice shapes created were documented with photographs, laser scanned surface measurements over a section of the model span, and measurement of the ice mass over the same section of each accretion. The icing conditions used in the test matrix were based upon previously used conditions on the same models but with an alternate approach to evaluation of drop distribution effects. Ice shapes resulting from the bimodal distribution as well as from equivalent monomodal drop size distributions were obtained and compared.
Technical Paper

Blocked Force Determination on Thin Plate Structures Including Applications

2019-06-05
2019-01-1525
Transfer path analysis is commonly used to determine input forces indirectly utilizing measured responses and transfer functions. Though it is recommended that the source should be detached from the vibrating structure when measuring transfer functions, engineers and technicians frequently have a difficult time in doing so in practice. Recently, a substitute for inverse force determination via transfer path analysis has been suggested. The indirectly determined forces are termed blocked forces and are usable so long as the source and machine are not detached from one another. Blocked forces have the added advantage of being valid even if the machine structure is modified. In this research, a typical automotive engine cover is considered as a receiver structure and is bolted to a plastic source plate excited by an electromagnetic shaker.
Technical Paper

Broadband Membrane-Type Acoustic Metamaterial Structures with Polymorphic Anti-Resonance Modes

2019-06-05
2019-01-1574
The researches indicate that rational design of membrane-type acoustic metamaterial (MAM) can make it have a high sound transmission loss (STL) at the anti-resonant frequency. Based on the principle of local resonance of acoustic metamaterials, this paper studied the coupling interactions between sound field and vibration modes, and designed four lightweight MAM structural units with different distributed harmonic oscillators, and then the anti-resonant behaviors of different units within the low frequency were gradually analyzed. The regulation mechanism of continuous polymorphic anti-resonance modes on broadening STL bandwidth was further revealed, and the STL characteristics have been verified within the low-frequency range by numerical simulation and experiments. The results show that the design of a single cross-shaped resonator can increase the diversity of anti-resonance modes and eliminate the node-circular-type resonance mode, then ensure the wider STL bandwidth.
Standard

Guidelines for Implementation of Structural Health Monitoring on Fixed Wing Aircraft

2019-05-16
WIP
ARP6461A
This document is applicable to civil aerospace airframe structural applications where stakeholders are seeking guidance on the definition, development and certification of Structural Health Monitoring (SHM) technologies for aircraft health management applications. For the purpose of this document, SHM is defined as “the process of acquiring and analyzing data from on-board sensors to evaluate the health of a structure.” The suite of on-board sensors could include any presently installed aircraft sensors as well as new sensors to be defined in the future.
Magazine

Autonomous Vehicle Engineering: May 2019

2019-05-02
Editorial AVs, data and 'surveillance capitalism' SAE AV Activities SAE launches Office of Automation The Navigator Lessons from the 737 Max-8 debacle Scorecard Waymo, GM and Ford pegged as autonomous leaders Designs to Dye for: Autonomy's New-Materials Revolution From pineapples to bacteria, Envisage's research is focused on new-mobility's 'inside' story. Dining on Data Processing, in real-time, the enormous data stream that's flowing through AVs is increasingly the job of NVIDIA's mighty GPUs. Danny Shapiro relishes the feast. New Performance Metrics for Lidar Frame-rate measurement is so yesterday.
Journal Article

Comparison Study of Malaysian Driver Seating Position in SAEJ1517 Accommodation Model

2019-04-08
Abstract A key element in an ergonomically designed driver’s seat in a car is the correct identification of driver seating position and posture accommodation. Current practice by the automotive Original Equipment Manufacturer (OEM) is to utilize the Society of Automotive Engineering (SAE) J1517 standard practice as a reference. However, it was found that utilizing such guidelines, which were developed based on the American population, did not fit well with the anthropometry and stature of the Malaysian population. This research seeks to address this issue by comparing the SAE J1517 Model against Malaysian preferred driving position. A total of 62 respondents were involved for the driver seating position and accommodation study in the vehicle driver’s seat buck mockup survey and measurements. The results have shown that the Malaysian drivers prefer to sit forward as compared to the SAE J1517 Model and have shorter posture joint angle.
Technical Paper

Experimental Study on Impingement of Fuel Droplet on Substrates

2019-04-02
2019-01-0300
Within a gasoline direct injection (GDI) engine, the impingement of fuel droplet on substrates induces various problems such as particular matter emission, oil dilution and abnormal combustion. Therefore, in order to solve these problems, it is urgent to have a clear understanding of the impingement behavior of fuel droplet impacting on substrates. Most previous studies have focused on the impingement of either water droplet on dry solid surface or the impinging droplet on the liquid film of the same type of liquid, while little research has been conducted on the impingement of fuel droplet on relevant substrates existing in GDI engines. The impingement of fuel droplet with higher Weber number on dry surface, fuel film and oil film with different thickness and viscosity were investigated experimentally. Results show that fuel droplet impacting on dry wall is easy to be deposited to form a fuel film. The fuel film attached to the wall is the main reason for the splash.
Technical Paper

Control Synthesis for Distributed Vehicle Platoon Under Different Topological Communication Structures

2019-04-02
2019-01-0494
The wireless inter-vehicle communication provide a manner to achieve multi-vehicle cooperative driving, and the platoon of automotive vehicle can significantly improve traffic efficiency and ensure traffic safety. Previous researches mostly focus on the state of the proceeding vehicle, and transmit information from self to the succeeding vehicle. Nevertheless, this structure possesses high requirements for controller design and shows poor effect in system stability. In this paper, the state of vehicles is not only related to the information of neighbor vehicles, while V2V communication transmit information over a wide range of area. To begin with, the node dynamic model of vehicle is described by linear integrator with inertia delay and the space control strategy is proposed with different topological communication structures as BF, LBF, PBF, etc.
Technical Paper

Research on Technique for Correction of Running Resistance with Focus on Tire Temperature and Tire Thermal Balance Model

2019-04-02
2019-01-0623
At present, measurements of running resistance are conducted outdoors as a matter of course. Because of this, the ambient temperature at the time of the measurements has a considerable impact on the measurement data. The research discussed in this paper focused on the temperature characteristic of the tires and developed a new correction technique using a special rolling test apparatus. Specifically, using a tire rolling test apparatus that made it possible to vary the ambient temperature, measurements were conducted while varying the levels of factors other than temperature that affect rolling resistance (load, inflation pressure, and speed). Next, a regression analysis was applied to the data for each factor, and coefficients for a relational expression were derived, making it possible to derive a quadratic equation for the tire rolling resistance correction formula.
Technical Paper

Multi-Wavelengths Michelson Interferometer Based Spatial Phase Shift Shearography with Color Camera

2019-04-02
2019-01-1269
The paper describes the use of a color camera for spatial phase shift shearography according to the carrier frequency method, whereby the focus is on measurement stability and practical usability. The basics are derived from the simple and extremely robust Michelson interferometer setup with spatial aperture and quality criteria are formulated according to the achievable result quality. The state of research of Multi-Wavelengths application is shown in general as well as in a publication, which serves as a further basis for comparison. The use of three laser sources and a Bayer-Matrix RGB color camera is considered to be the most effective method for the following development. For this purpose, the 3 out-of-plane illumination arrangement is used, which provides the three separate results in the spatial directions in only one measurement (for shear direction in x).
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