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In a new, rapidly evolving domain like eVTOL, simulation plays a vital role. Manufacturers are focused not just on training pilots, but also on using simulators in aircraft design, maintenance, and air traffic management.
Companies with interests in the aerospace and defense simulator domain are turning their attention to eVTOLs in the expectation of significant market growth over the coming decade. For example, Dassault Systèmes expects the platforms “to continue to gain traction and become the next medium for urban mobility,” said Francesco Polidoro, director – Simulia Aerospace and Defense at the company.
Simulia is Dassault Systèmes’ specialist simulation brand, developing software for multiple vehicle types and sectors within the broader aerospace and defense domains and beyond. Polidoro said the company has focused on the potential for its Simulia PowerFLOW in the design of air taxis, and has seen “a lot of traction” in the market over the past two years. While he could not provide further details, he said that Dassault Systèmes Simulia works with both startups and large aerospace companies in the U.S., Europe, and China.
The software is used to predict the aeroacoustics of the vehicle and its rotors, with the simulation allowing manufacturers to understand how the noise is generated and how it propagates to the interior of the cabin or the ground. Noise is key to eVTOLs, Polidoro said, and will have a major impact on when — or even if — the systems are accepted by the public. In traditional aviation platforms, Polidoro said, noise is often considered at the end of the development cycle, with the aim of meeting a particular regulatory requirement. For eVTOLs, however, noise is one of the main focus areas, and a major challenge in designing simulations in the area.
That challenge could deepen if and when the vehicles become autonomous, Polidoro said. While piloted platforms can choose different trajectories to minimize noise over certain parts of an urban landscape, autonomous systems would have to be taught to recognize such trajectories. PowerFLOW can be used to build databases of noise emissions that can serve as the foundation of autonomous trajectory planning, allowing the system to anticipate noise emissions in real time based on particular flight conditions and account for this.
“While other aviation platforms can rely on years of know-how and experience, these new concepts use simulation as the way to verify design choices and accelerate the vehicle development,” said Polidoro.
The company hopes its aeroacoustics simulations “help engineers to understand and visualize the noise sources and improve designs efficiently,” allowing them to include noise as a design parameter from the start of the development process, when prototypes are not available. Using simulations can help improve the design while reducing development costs, he added.
Bell is using simulators to gather data for its Future Flight Controls program, which will produce fly-by-wire controls for eVTOL platforms like the company’s Nexus, along with next-generation helicopters more broadly. Simulators are being deployed in research and development for the controls, said Jim Gibson, who is the lead of Future Flight Controls. Prospective eVTOL pilots use the simulators in various maneuvers, with Bell using the data collected along with other information to determine the most effective designs for the controls.
Bell also uses simulators in a range of other areas related to eVTOL, Gibson said. For example, he said there is a large role for simulators in training mechanics. Normally they will interact with onboard computers via the cockpit, searching through different menus to find the status of different types of equipment and so on; simulators can be used to teach them how to do this. Gibson also highlighted simulators’ capacity to incorporate both virtual reality and augmented reality to allow maintainers to look at the equipment and components of the aircraft.
“Simulators are a great way to teach them all the procedures they need to know to find and download that information and ultimately service the aircraft,” he said.
Even if eVTOL are eventually fully autonomous, there will still be a need to train the personnel who will oversee the UAS traffic management systems (UTM) in urban landscapes. This is another important focus area for simulators, Gibson said, allowing them to practice controlling the movement of aircraft in and out of high-density areas.
In general, simulators in eVTOL offer significant practical benefits, Gibson said; for example, they allow users to easily reset a particular maneuver, rather than land the aircraft and begin again, saving time.
“Not only can you do effective training, but you can reduce the time required to achieve the same training,” he added.
UBER Elevate and aircraft development partners Aurora, Bell, Karem and Embraer among many others use Continuum Dynamics, Inc.’s CHARM software for fast mid-fidelity analysis of the aerodynamics of eVTOL air-taxi concepts. An automated coupling between CHARM and The Pennsylvania State University PSU-WOPWOP code allows fast, accurate acoustic predictions for eVTOL aircraft including key interactional aerodynamics effects. The eVTOL aircraft aeroacoustic modeling capabilities of CHARM and PSU-WOPWOP are continually being enhanced through NASA, DoD and FAA-funded R&D.
Looking for an opensource high-fidelity aerodynamics and aeroacoustics solver for maneuvering eVTOL simulations? Check out FLOWUnsteady https://github.com/byuflowlab/FLOWUnsteady
FLOWUnsteady is a mixed-fidelity simulation framework based on the viscous vortex particle method (VPM) for maneuvering multirotor aircraft without the prohibitive computational cost of conventional CFD methods. The viscous VPM is a mesh-free CFD method for the numerical solution of the Navier-Stokes
equations in their vorticity form, which is especially well fitted for resolving wake dynamics. This approach is a direct numerical simulation that efficiently preserves vortical structures in a Lagrangian scheme, eliminates the complexities of mesh generation, is absent of the numerical dissipation associated with mesh-based CFD,
and is about two orders of magnitude faster than conventional CFD methods. In our framework, wings and rotating blades are modeled through a combination of panel, lifting line, and blade elements, while
wake dynamics are solved through VPM, accurately capturing rotor-rotor, rotor-wing, and wing-wing aerodynamic interactions, while coupling with PSU-WOPWOP for noise analysis.
Any thought on how weather will be integrated into the overall simulation activities you outlined. As an example for the last several days we have had freezing weather in the Dallas area. Any e VTOL platform not geared for that type of environment would find its rotors quickly encrusted in ice and falling like a rock. Weather will play a key role in the success or failure of eVTOL acceptance
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