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How Thunderbolt 4 Helps Bring Fault-Tolerant, Distributed Systems to Market Delivering Operational Energy to Enhance Warfighter Capability Optoelectronic Analog Signal Transmission Takes Center Stage Amidst Aerospace and Defense Innovation Shaking Outside the Box to Advance Flight Research An Introduction to Quantum Computing How Laser Communications Innovation is Finally Coming of Age and Driving Innovation in Defense Spatial Calibration for Accurate Long Distance Measurement Using Infrared Cameras A new spatial calibration procedure has been introduced for infrared optical systems developed for cases where camera systems are required to be focused at distances beyond 100 meters. Towards Greater Sensitivity: A Brief FTIR and Infrared-Based Cavity Ring Down Spectroscopy Comparative Study A presentation of work comparing efficacy of a traditional IR method used as a standard within the U.S.

An introduction to Archer Aviation and perspectives on urban air mobility certification.

If an Unmanned Aerial Systems (UAS) encounters icing conditions during flight, those conditions might result in degraded aerodynamic performance of the overall UAS. If the UAS is not reacting appropriately, safety critical situations can quickly arise. ...The experimental tests featured various rotors which were exposed to icing conditions without any protective measures to better understand the influence of ice accretion on the aerodynamic performance. In addition, possible technical solutions in form of an electrothermal and chemical anti-/de-icing system, as well as an ice-repellent surface coating were investigated.

Data gathering included the delta-pressure across the IBF, static pressures at the Aerodynamic Interface Plane (AIP), engine parameters, high-speed camera imagery, and 3-D scans of the critical ice shapes.

The results are analyzed to identify the dynamics of the electrical, mechanical, and aerodynamic subsystems of the propulsion system. Moreover, the parameters of the identified models are presented, making it possible to analyze their sensitivity to ice accretion on the propeller blades.

The UAV’s aerodynamic stability is also considered by meeting lift requirements, producing enough thrust, and having battery capacity left.

In-flight icing can result in severe aerodynamic performance penalties for unmanned aerial vehicles. It is therefore important to understand to which extent ice will build up on fixed-wing unmanned aerial vehicles wings and empennages, namely rudder and elevator, and how this ice will impact the aerodynamic performance and limits the flight envelope. ...It is therefore important to understand to which extent ice will build up on fixed-wing unmanned aerial vehicles wings and empennages, namely rudder and elevator, and how this ice will impact the aerodynamic performance and limits the flight envelope. This work investigates numerically icing effects on wing and empennage over a wide range of icing parameters. ...The results of the simulations are used to calculate the change in the lift coefficient cl, the drag coefficient cd and the momentum coefficient cm, and an estimate of the total accreted ice mass. The aerodynamic performance penalties are strongly dependant on the environmental conditions. For both icing envelopes, two different worst case conditions are identified.

Three Reynolds number and Mach number combinations were tested over a range of angles of attack. Aerodynamic forces and moments were acquired from the tunnel balance and surface pressures and oil flow visualizations were acquired. ...Additional surface roughness was added to simulate large-droplet ice accretion aft of the highly three-dimensional primary ice shape, and it had little effect on the wing aerodynamic performance. Spanwise ridge simulations produced large increases in drag and small increases in maximum lift in most cases. ...Studies of a partial-span ridge simulating a residual icing case and additional simple horn cases to supplement SWIP data are also presented. The aerodynamic performance results from the simple horn ice cases are consistent with the previously identified trends in earlier studies with a more limited range of horn angles.

Relevant aspects include sizing of the main aerodynamic surfaces, provision of anti-icing systems, and setting of operational restrictions. ...This paper describes a CFD-based investigation of the effects of sweep on the aerodynamic performance of a novel forward-swept horizontal stabilizer concept in icing conditions. ...In-flight ice accretion was calculated, using Ansys FENSAP-ICE, on 10°, 15° and 20° (low, intermediate, and high) sweep horizontal stabilizers, with the tail as attached to the full-scale aircraft, for a 45-minute holding pattern. The aerodynamic analyses of the iced tails were carried out using Ansys Fluent Aero with angle of attacks from 0° to -15°.

Ice horns formed at temperatures close to freezing and the flow separation aft of the ice led to significant aerodynamic penalties. The 3D ice accretion simulation of the 80-inch rotor shows discrepancies with the 2D results as it does not predict ice accretion at the outer region of the blades at – 15 °C. ...The performance degradation simulations show that ice accretion causes significant aerodynamic penalties, especially in cases where horn ice accretion forms. Finally, the anti-icing loads required to mitigate ice accretion thermally were calculated.

Various icing incidents occurred due to severe degradation of aerodynamic performance, and engine rollbacks. As in-flight icing can occur over a broad range of atmospheric and flight conditions, design of effective ice protection mechanisms on aero-components is essential.

Rollback, surge and stall events are known to have been instigated through such accretions due to aerodynamic losses related to ice growth, damage and flameout due to ice shedding. The prevalence of these events has led to a change in certification requirements for icing conditions.

Therefore, performing sensitivity analysis (SA) or uncertainty quantification (UQ) studies is not only essential to determine the influence of uncertainties on the ice shape and aerodynamic performance but also crucial to identify the most significant icing parameter uncertainty.

Wind turbines in cold climates are likely to suffer from icing events, deteriorating the aerodynamic performances of the blades and decreasing their power output. Continuous ice accretion causes an increase in the ice mass and, consequently, in the centrifugal force to which the ice shape is subjected.

Predicting the aerodynamic performance of an aircraft in icing conditions is critical as failures in an aircraft’s ice protection system can compromise flight safety. ...Predicting the aerodynamic performance of an aircraft in icing conditions is critical as failures in an aircraft’s ice protection system can compromise flight safety. Aerodynamic effects of icing have typically relied on RANS modeling, which usually struggles to predict stall behavior, including those induced by surface roughness.

For this purpose, a method for ice accretion prediction on a selected airfoil, NACA 22112, is proposed in this study with different surrogate models that will later be used for fast prediction in 6DOF simulations to directly evaluate its effects on aerodynamic performance during flight. The required datasets in order to train for clean and iced airfoils are based on numerical analysis results obtained through the FENSAP-ICE 2022 R1 commercial tool with a multi-shot technique.

The in-flight ice accretion simulations are typically performed using a quasi-steady formulation through a multi-step approach. As the ice grows, the geometry changes, and an adaptation of the fluid volume mesh used by the airflow and droplet-trajectory solver is required. Re-meshing or mesh deformation are generally employed to do that. The geometries formed are often complex ice shapes increasing the difficulty of the re-meshing process, especially in three-dimensional simulations. Consequently, difficulties are encountered when trying to automate the process. Contrary to the usual body-fitted mesh approach, the use of immersed boundary methods (IBMs) allows solving, or greatly reducing, this problem by removing the mesh update, facilitating the global automation of the simulation. In the following paper, an approach to perform the airflow and droplet trajectory calculations for three-dimensional simulations is presented. This framework utilizes only immersed boundary methods.

The stresses internal to the ice shapes when subjected to the aerodynamic loads are compared with the mechanical properties of ice such as the tensile and adhesion strength.