Computational Simulations of Next-Generation Aircraft

Overview

NASA has several initiatives with strategic goals to reduce emissions, fuel burn, and noise levels for next-generation aircraft. These aircraft include the fuel-efficient transonic truss-braced wing (TTBW), the all-electric X-57 Maxwell, and the X-59 QueSST, designed with quiet supersonic technology. Researchers at NASA’s Ames Research Center are assessing next-generation technologies utilized in these designs, and validating results against experimental data. The Pleiades supercomputer is used to produce steady-state flow simulations required for each project team to better understand the performance of these highly complex vehicles.

Project Details

The Launch Ascent and Vehicle Aerodynamics (LAVA) group at NASA Ames performs computational fluid dynamics (CFD) analysis for a variety of cutting-edge aircraft concepts to support the agency’s aeronautics missions. The TTBW is one of five concepts for ultra-efficient subsonic transport design efforts aimed at maximizing fuel efficiency at transonic speeds. One of the main challenges in analyzing this design is accurately predicting aerodynamic loads that agree well with experimental data collected in wind tunnel tests.

Supporting the goal of environmentally friendly aviation, NASA’s X-57 concept plane utilizes electric propulsion. To achieve this, 12 battery-powered high-lift propellers are equally distributed across each wing, with two main propellers placed at the wing tips to provide the main thrust. This configuration utilizes distributed propulsion technology, which provides accelerated flow during takeoff and landing when higher lift is required over the wing. The LAVA team created an aerodynamic database that will fully characterize the aircraft’s performance.

The X-59 QueSST is being used to demonstrate the feasibility of a low-boom supersonic aircraft. Using advanced shaping of the plane and other techniques, the X-59 is designed to produce a lower sound signature that will not significantly disturb people on the ground. This will be tested by flying the aircraft over selected communities and gathering data from residents in the flight path. The biggest challenge associated with this project is accurate prediction of the sound profile produced by the vehicle in a variety of flight scenarios.

Results and Impact

The LAVA CFD results for these designs will reduce the risk and cost for each project. Through analysis on the TTBW, the LAVA team helped identify the sources of discrepancies between the CFD results and wind tunnel data. For the X-57, the aerodynamic database created by the team will be used to develop the flight controls. In addition, through CFD simulations, LAVA demonstrated that the X-59 design meets all noise requirements established by the project. All these simulations allow informed recommendations and insights to be shared with design teams, helping to ensure the success of these projects to advance air transportation technology for the next generation of aircraft.

Why HPC Matters

The steady-state flow simulations for each aircraft are run on the Pleiades and Electra supercomputers at the NASA Advanced Supercomputing facility. For the TTBW, calculations ranged from 14.5 million – 105 million grid points and 140 – 1,000 processors respectively, and ran for 8 hours of wall-time each. For the X-57, calculations ranged from 60.1 million – 426 million grid points, which required 720 to 2,400 processors respectively, and ran for 24 hours of wall-time each. For the X-59, calculations ranged from 32 million – 100 million cells, which required 1,800 to 5,600 processors respectively, and ran for 5 hours of wall-time each. All simulations are run on Intel Xeon Ivy Bridge or Skylake nodes.

More Information

• NASA’s Experimental Supersonic Aircraft Now Known as X-59 QueSST
• X-57 Maxwell
• See the poster for this demonstration (PDF, 1.8MB). As shown in the NASA booth at SC18.