Dr. Vivek Ahuja, Research In Flight

FlightStream: Propulsion-airframe Interactions on Urban Air Mobility Electric Aircraft
October 9, 2020


The emergence of Distributed Electric Propulsion (DEP) and the Urban Air Mobility (UAM) application has added a new paradigm to the aircraft design problem. Distributed propulsion is also a common theme in the emerging V/STOL UAM concepts in the industry, where highly unconventional design configurations use larger numbers of propeller/rotor-based propulsors, often in conjunction with fixed or tilting wings. As such aerodynamics and propulsion analysis, control effector authority, gust/turbulence rejection or load alleviation, and occupant ride quality must be addressed in greater detail much earlier in the design process. FlightStream® has been developed by Research in Flight as a fast, accurate, flow solver based on surface-vorticity on the outer mold line of an aircraft. Aerodynamic loads are computed by shedding vorticity from the geometry. FlightStream® makes use of the resolved surface-vorticity to compute aerodynamic load distributions using the advanced Cartesian Hierarchical Fast Multipole Method and automatic vortex wake proximity avoidance algorithms. FlightStream® allows for non-linear aerodynamics, including unsteady-flow, prediction of the onset of stall, maximum lift coefficient prior to stall; and post-stall aerodynamics for subsonic flows. This allows FlightStream® to generate aerodynamic results in seconds and minutes for multi-rotor simulations.


Dr. Vivek Ahuja

Cofounder of Research in Flight and the Program Director for FlightStream® at Research in Flight. He holds a Ph.D. in Aerospace Engineering from Auburn University (2013). Dr. Ahuja has developed many innovations with surface vorticity for high-lift flow, primarily a novel vorticity strain-based flow separation theory that allows for the prediction of stall and post-stall aerodynamics using surface-bound vorticity. Other innovations include advanced formulations of viscous drag models using vorticity. He has authored 30+ technical papers on these topics at conferences and in journals. Dr. Ahuja has held CFD positions in both the oil-and-gas industry and in the commercial CFD industry. He is also the PI on many NASA SBIR, STTR, and TTT technical contracts in which the Research in Flight Company has developed advanced high-lift aerodynamic prediction capabilities using FlightStream®.