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Aeroacoustics of Space Vehicles

AMS Seminar Series

Speaker: Jayanta Panda, Experimental Flow-Physics Branch, NASA Ames Research Center

Presentation

Seminar Slide Deck (PDF-10MB)

Abstract

While for airplanes the subject of aeroacoustics is associated with community noise, for space vehicles it is associated with vibro-acoustics and structural dynamics. Surface pressure fluctuations encountered during various launch events create intense vibro-acoustics environment for the payload, electronics and navigational equipment, and a large number of subsystems. All of these components have to be designed and tested for flight-certification. This presentation will cover all three major sources encountered in manned and unmanned space vehicles: launch acoustics, ascent acoustics and abort acoustics. Launch pads employ elaborate acoustic suppression systems to mitigate the ignition pressure waves and rocket plume generated noise during the early part of the liftoff. Recently we have used large microphone arrays to identify these sources and found that the standard model by Eldred and Jones (NASA SP-8072) to be grossly inadequate. As the vehicle speeds up and reaches transonic speed in relatively denser part of the atmosphere, various shock waves and flow separation events create unsteady pressure fluctuations that can lead to high vibration environment, and occasional coupling with the structural modes, which may lead to buffet. Examples of wind tunnel tests and computational simulations to optimize the outer mold line to quantify and reduce the surface pressure fluctuations will be presented. Finally, a manned space vehicle needs to be designed for crew safety during malfunctioning of the primary rocket vehicle. This brings the subject of the acoustic environment during abort. For NASA's Multi-Purpose Crew Vehicle (MPCV), abort will be performed by lighting rocket motors on the top of the crew module. The severe aeroacoustics environments during various abort scenarios were measured by using hot helium to simulate rocket plumes in the Ames unitary plan wind tunnels. Various considerations used for the helium simulation and the final confirmation from a flight test will be presented.

Biography

Photo of Jayanta Panda
Jayanta Panda did his B.E and M.E in India and his Ph.D. in Aerospace Engineering from the Pennsylvania State University in 1990. His thesis work was on the fundamental turbulence study and aeroacoustics of free jets. After graduation he joined NASA Glenn Research center as a NRC fellow and continued working through the Ohio Aerospace Institute for 18 years. He joined the Experimental Flow-Physics branch of NASA Ames in 2008. His 60+ research papers show contributions on a variety of subjects spanning fundamental physics of noise generation, to various aeronautical and space applications. Currently he has been working on the aeroacoustics issues of MPCV and SLS vehicles.