Dynamic Delegated Corridors and 4D Required Navigation Performance for Urban Air Mobility (UAM) Airspace Integration

Increased traffic congestion on urban road networks has impacted the travel time for commuters in highly populated urban centers. Urban Air Mobility (UAM) is recognized as a system that transports the passenger and air cargo from any location to any destination within a metropolitan area. UAM may offer a solution to the problematic issue of automobile urban surface transportation congestion. However, the predicted significant growth in the demand for integration of UAM operations into the existing airspace system in the next 20 years and beyond may exceed the capacity of current air traffic control (ATC) system resources, particularly the ATC workload. Many organizations in the aviation industry, academia, and government have conducted extensive studies on the issue of UAM airspace integration. Many of these proposed solutions involve high-level frameworks for managing UAM operations. In this paper, the combination of the Dynamic Delegated Corridors (DDCs) and full four-dimensional (4D) Required Navigation Performance (RNP) trajectories are proposed to enable UAM aircraft to integrate into the existing airspace system. Experiments will be conducted to measure and compare the ATC workload before and after the installation of DDCs and 4D RNP trajectories in the terminal control area (TCA) of an airport. The proposed approach in this paper is expected to help reduce the workload of ATC dramatically and contribute to the viability of UAM airspace integration into the existing airspace system to operate at low altitudes in the terminal controlled airspace together with other airspace users safely and efficiently

Unmanned Aerial Systems (UAS) Integration into the National Airspace System (NAS)

NASA's Unmanned Aerial Systems (UAS) integration into the National Air Space (NAS) project has been working closely with the FAA and RTCA Special Committee 228 to identify and break down barriers to UAS integration. A focus of this work is on detect and avoid (DAA) technologies. A pilot has responsibility to see and avoid other aircraft and to remain "well clear," using their best judgment (Federal Aviation Regulations (FAR) Sec. 91.113). For UAS to perform this function, the see function is replaced by sensors to detect the other aircraft. Secondly, the pilot judgment of well clear has to be replaced by a mathematical expression. For Phase 1 of this effort, a well clear violation was defined if all three of these conditions are true: a) the horizontal clearance is less than 4000 ft., and b) the vertical clearance is less than 450 ft., and c) the time to loss of well clear is less than 35 seconds. This definition was developed with a great deal of community input and testing to ensure interoperability with Air Traffic Control (ATC) and pilots of manned aircraft. Appropriate guidance, alerting and displays were developed to allow UAS, with the appropriate sensors, to effectively maintain well clear. This work contributed to FAA Technical Standard Orders: TSO-C211, Detect and Avoid and TSO-C212, ATAR for Traffic Surveillance. Phase 2 of this work extends the operational environment to include the terminal area and lesser capable aircraft that might not have the payload capability to carry the RADAR defined in Phase 1. This session reports on work from Phase 1 and initial work in Phase 2

Steady and Unsteady compressible Reduced-Order Models of a Zero-Net Mass-Flux Synthetic Jet Actuator

International audienceIn the framework of an optimization study of a Zero-Net-Mass-Flux fluidic, synthetic jet actuator, based on a multi-objective optimization formulation, the consideration of optimization parameters such as the actuator location and the outlet design implies a re-meshing procedure that adds complexity. It is still the case even if the actuator is modeled with simple boundary conditions at the jet orifice exit since, locally, the re-mesh is still required. This strongly impacts the global computational cost, in particular if the considered geometry is complex. In a previous study, we proposed an alternative method to model Zero-Net Mass Flux synthetic jet actuators through the implementation of volumetric reduced-order models (ROM) as additional source terms. The previous reduced-order model consisted in a simplified ROM model where a constant-in-space momentum quantity was imposed in the ROM formulation and the compressible effects were neglected. In this paper, we propose to extend the previous work in an attempt to apply this ROM strategy to higher Mach number flows, where compressibility effects at the outlet of the pulsed jets can no more be neglected, while improving the early interaction of the pulsed jet with the surrounding flow by considering the starting jet influence when the actuators are operated in a pulsed manner

Distributed Electric Propulsion : a Technology requiring Multi-Disciplinary Aircraft Design

Performance enhancement of Distributed Electric Propulsion for transport aircraft is discussed through an example case study: the reduction of vertical tail, replaced by additional control offered by differential thrust. The multidisciplinary aspects of this design and the means to treat them are presented

Temporal Stabilisation of Flux Reconstruction on Linear Problems

Filtering is often used in Large Eddy Simulation with a global filter width, instead here a filter width in the reference domain of high order Flux Reconstruction is considered. It is shown via Von Neumann analysis how filtering effects the dispersion and dissipation of the scheme when spatially and temporally discretised. With it being shown that filtering stabilises the scheme temporally by upto $25\%$ for forth order FR. The impact of filtering on error production is calculated, highlighting the reduction in convective velocity caused and showing numerically the impact on order of accuracy. Finally, the turbulent Taylor-Green case is used to understand the effect of reference domain filtering on the transition to turbulence, and a filter Reynolds number is defined that is shown to be useful in understanding the effect of filtering on simulations.Comment: AIAA Aviation Forum June 201

A Machine Learning Approach Towards Analyzing Impact of Surface Weather on Expect Departure Clearance Times in Aviation

Commercial air travel in the United States has grown significantly in the past decade. While the reasons for air traffic delays can vary, the weather is the largest cause of flight cancellations and delays in the United States. Air Traffic Control centers utilize Traffic Management Initiatives such as Ground Stops and Expect Departure Clearance Times (EDCT) to manage traffic into and out of affected airports. Airline dispatchers and pilots monitor EDCTs to adjust flight blocks and flight schedules to reduce the impact on the airline’s operating network. The use of time-series data mining can be used to assess and quantify the impact of surface weather variables on EDCTs. A major hub airport in the United States, Charlotte Douglas International Airport, was chosen for the model development and assessment, and Vector Autoregression and Recurrent Neural Network models were developed. While both models were assessed to have demonstrated acceptable performance for the assessment, the Vector Autoregression outperformed the Recurrent Neural Network model. Weather variables up to six hours before the prediction time period were used to develop the proposed lasso regularized Vector Autoregression equation. Precipitation values were assessed to be the most significant predictors for EDCT values by the Vector Autoregression and Recurrent Neural Network models

Steady and Unsteady compressible Reduced-Order Models of a Zero-Net Mass-Flux Synthetic Jet Actuator

In the framework of an optimization study of a Zero-Net-Mass-Flux fluidic, synthetic jet actuator, based on a multi-objective optimization formulation, the consideration of optimization parameters such as the actuator location and the outlet design implies a re-meshing procedure that adds complexity. It is still the case even if the actuator is modeled with simple boundary conditions at the jet orifice exit since, locally, the re-mesh is still required. This strongly impacts the global computational cost, in particular if the considered geometry is complex. In a previous study, we proposed an alternative method to model Zero-Net Mass Flux synthetic jet actuators through the implementation of volumetric reduced-order models (ROM) as additional source terms. The previous reduced-order model consisted in a simplified ROM model where a constant-in-space momentum quantity was imposed in the ROM formulation and the compressible effects were neglected. In this paper, we propose to extend the previous work in an attempt to apply this ROM strategy to higher Mach number flows, where compressibility effects at the outlet of the pulsed jets can no more be neglected, while improving the early interaction of the pulsed jet with the surrounding flow by considering the starting jet influence when the actuators are operated in a pulsed manner