NASA SBIR 2003 Solicitation


PROPOSAL NUMBER:03-A2.04-8581 (For NASA Use Only - Chron: 034424)
SUBTOPIC TITLE:Airframe Systems Noise Prediction and Reduction
PROPOSAL TITLE:High Order Wavelet-Based Multiresolution Technology for Airframe Noise Prediction

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
CFD Research Corp
215 Wynn Dr.
Huntsville ,AL 35805 - 1926
(256) 726 - 4800

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Essam F. Sheta
215 Wynn Dr.
Huntsville ,AL  35805 -1926
(256) 726 - 4800
U.S. Citizen or Legal Resident: Yes

An integrated framework is proposed for efficient prediction of rotorcraft and airframe noise. A novel wavelet-based multiresolution technique and high-order accurate WENO scheme is proposed for efficient capturing of noise sources and unsteady flowfield. A wavelet compression is used to store the flowfield as a multi-level representation in functional space. The primary solution progresses using a coarse grid. The regularity of the flow field data is used to identify regions of steep variation. These regions are selectively solved recursively in the finer grid-levels and accurate information is injected into the coarse grids to correctly represent all flow features.

In Phase I, a three-dimensional wavelet-based multiresolution algorithm, and an acoustic analogy module based on the Kirchhoff-Ffowcs Williams and Hawking methodology will be developed. The feasibility of the proposed technology will be demonstrated by prediction of three-dimensional noise source and acoustic waves of vortex-blade interaction problems. The proposed technology will provide 2-3 orders-of-magnitude reductions in CPU requirements over existing techniques. In Phase II, the wavelet compression methodology will be integrated into a high-fidelity CFD module. An efficient data structure will be developed to store and update the multiresolution data. The modules will be coupled with a nonlinear finite-element structure dynamic module for noise prediction of flexible structures.

The proposed framework will provide 2-3 orders-of-magnitude reductions in computational time for high-order accurate noise prediction and wake capturing. The framework will be directly applicable to several NASA's multidisciplinary noise and vibrations applications such as prediction of noise mechanisms and propagation for rotorcraft, propellers, and other airframes, and for analysis of wake/frame interaction induced noise and vibrations. The framework could also be used for other NASA's commercial applications such as flutter and buffet analysis of helicopter, fighter aircraft, nonlinear lift systems, analysis of active twist rotors.

The proposed technology provides a viable tool for several commercial applications such as wing-trailing vortex dynamics of large civil aircraft, analysis of noise generated by landing gears of civil aircraft. The multiresolution technology is also applicable to a wide range of applications that involve embedded flow features requiring high resolutions. Such applications include Turbomachinery, Cavitation, Biomedical, Electronic Cooling, and many others.