Engineering Papers⌕ Search

Engineering topics

Cadieux, Francois

Publications and source records attributed to Cadieux, Francois.

18 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

Predicting Quadcopter Drone Noise Using the Lattice Boltzmann Method

The market for new vertical takeoff and landing vehicles, including autonomous urban air taxis and drones for applications such as package delivery, imaging, and surveillance, is growing rapidly. However, aerodynamic noise continues to be the biggest roadblock to community acceptance and adoption. To predict the aerodynamic noise generated by an isolated quadcopter drone, derived from from first principles, we used the Lattice Boltzmann flow solver within NASA’s Launch Ascent and Vehicle Aerodynamics (LAVA) solver framework. The solver’s computational efficiency, and the complete absence of labor-intensive manual volume mesh generation in the workflow, are key to making routine aeroacoustic analysis of urban air taxis and drones from first principles possible.

Cadieux, Francois↗
NASA NTRS2018

High-Resolution Launch Environment Simulations

After many years of harsh rocket launches, the Main Flame Deflector (MFD) at Kennedy Space Center has been upgraded in anticipation of flights of NASA’s next generation Space Launch System. The new MFD has a much easier to maintain shingled steel surface.

Launch↗
NASA NTRS2018

Wall-Modeled Lattice Boltzmann and Navier-Stokes Approaches for Separated Flows

Lattice Boltzmann (LB) and hybrid Reynolds-averaged Navier-Stokes/large eddy simulation (RANS/LES) methods within the Launch Ascent and Vehicle Aerodynamics (LAVA) solver framework are applied to NASA's Revolutionary Computational Aerosciences (RCA) standard test cases for separated flows. A detailed comparison between the performance and accuracy of the two emerging numerical methodologies for turbulence resolving simulations, i.e. the LB and hybrid RANS/LES methods will be presented. This contribution addresses the RCA technical challenge to identify and down-select critical turbulence, transition, and numerical method technologies for 40% reduction in predictive error for standard turbulence separated flow test cases. Results for the 2D NASA wall-mounted hump and the axisymmetric transonic bump including time-averaged pressure coefficient, skin friction, and velocity pro les, as well as resolved and modeled Reynolds stresses for both numerical approaches will be presented and differences between LB and hybrid RANS/LES will be discussed.

Lattice Boltzmann↗
NASA NTRS2018

Aerodynamic Shape Optimization of the STARC-ABL Concept for Minimal Inlet Distortion

The NASA single-aisle turboelectric aircraft with an aft boundary layer propulsor (STARC-ABL) concept utilizes a novel electrically driven aft fan that ingests the fuselage boundary-layer for increased propulsive efficiency. In this paper we examine how aerodynamic shaping of the fuselage diffuser and nacelle inlet can reduce the flow distortion at the aft fan. Adjoint-based aerodynamic shape optimization with the ARP1420 distortion metric objective is used to automatically determine the optimal shapes for minimal fan-face distortion. Single and multipoint optimizations are carried out for simplified body-duct and wing-body-duct configurations. These two configurations highlight the importance of including the wing downwash effects when designing the propulsor. The optimizations showed the body-duct configuration can obtain cruise distortion values of approximately 1% while the wing-body-duct configuration can obtain distortion values of just over 2%.

Kenway, Gaetan K. W.↗