NASA SBIR 2003 Solicitation


PROPOSAL NUMBER: 03- II A2.04-8581
SUBTOPIC TITLE: Airframe Systems Noise Prediction and Reduction
PROPOSAL TITLE: High Order Wavelet-Based Multiresolution Technology for Airframe Noise Prediction

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Essam F. Sheta
215 Wynn Dr., 5th Floor
Huntsville, AL 35805-1926
U.S. Citizen or Legal Resident: Yes

We propose to develop a novel, high-accuracy, high-fidelity, multiresolution (MRES), wavelet-based framework for efficient prediction of airframe noise sources and acoustic propagation. In Phase I, 2D and 3D models of MRES methodology were developed. An acoustic analogy module based on Ffowcs Williams and Hawking technique was developed to accurately propagate the near-field acoustic signals to far field with minimal dissipation and dispersion. An innovative Runge-Kutta temporal update was developed to advance all grid levels independently. The feasibility and accuracy of the MRES technology was demonstrated by predicting noise sources and acoustic waves generated by vortex shedding. The Phase I results indicate that the proposed technology will provide up to two orders-of-magnitude reductions in CPU time over existing techniques.

In Phase II, we propose to improve the 3D MRES software to handle multi-block, curvilinear, viscous and massively parallel applications. An efficient data structure will be developed and implemented to store and update the multiresolution data to improve the cost-saving factor. Unsteady turbulence models based on DES and PANS will be implemented to better resolve the sources of noise. The acoustic module will be improved to account for surface motions and quadrupole source terms. The developed modules will then be coupled to a large-scale CFD code to expand the application base of the technology. The technology will be demonstrated and validated using typical aeroacoustic applications such as Energy Efficient Transport (EET) airfoils and landing gear models.

The proposed technology provides a viable tool for several commercial applications such as wing-trailing vortex dynamics, noise generated by landing gear, blade vortex interaction (BVI), and BVI induced noise. The multiresolution technology is needed in a wide range of applications that involve unsteady and embedded flow features requiring high resolutions. Such applications include combustion instabilities, chemical and biological plume dispersion, missile plume signatures, turbo-machinery, micro-fluidic systems, cavitations, biomedical, electronic cooling, and many others. The MRES technology has recently received the attention of several aerospace companies. In particular, Lockheed Martin has expressed its interest in utilizing the MRES capabilities in their computational aeroelasticity framework.

The proposed technology provides substantial reductions in computational time for complex, unsteady computations. This is extremely beneficial to several NASA multidisciplinary noise and vibrations applications such as noise source identification on Energy Efficient Transport (EET) high lift vehicles, landing gears, advanced rotor tip shapes, jet noise, rotorcraft and propellers. The framework could also be used for other NASA applications, such as flow control via jet blowing, suction, or synthetic jets, flutter and buffet analysis of helicopters and fighter aircraft, nonlinear lift systems, active twist rotors, missile plume signatures, and micro air-vehicles analysis.