NASA SBIR 00-II Solicitation


PROPOSAL NUMBER: 02.02-8624 (For NASA Use Only - Chron: 001377 )
PROPOSAL TITLE: Turbulence Framework for Jet Noise Prediction and Reduction

Practical jet noise prediction for realistic geometries requires accurate RANS-based inputs regarding mean and turbulent flow quantities. Such information is currently unavailable; our proposed innovation seeks to remedy this issue. Phase I results yielded a preliminary turbulence model (EASM/J) extensively tested against fundamental shear flow data and detailed 3D-PIV measurements for a cold jet. Highlights included demonstrating that jet turbulent anisotropy, which affects noise, has unexpected complex variations, particularly for separate flow nozzles with passive mixing. One task in Phase II will upgrade MGBK to account for these observations given advanced CFD inputs. Phase II work will also extend the baseline EASM/J to more accurately account for the effects of compressibility and hot jets on mean and turbulent flow structures (and hence noise). A unique aspect to our development approach is direct support from both PIV and LES for providing critical modeling details. Laser speckling will also be performed to resolve differences between time-averaged (measured) and Favre-averaged (modeled) quantities. This effort will also include investigating complex jets, including shocks and chevrons. The final product is an advanced CFD tool capable of supporting noise reduction studies, evaluating complex plume flowfields, and providing noise prediction information to an improved version of MGBK.

Commercial applications entail direct extension to existing work supporting DoD contractors for plume IR applications via: (1) software licensing of a specialized and validated propulsive code with increased accuracy; (2) consulting support; and (3) direct performance of very challenging plume-related problems. IR applications for conventional aircraft and missiles require accurate representation of only the mean flow structure. Via the advanced turbulence development proposed during Phase II, our scope of current commercial applications can be greatly expanded to include supporting:

(1) commercial and military aircraft noise reduction problems, which require details of the turbulent anisotropy;
(2) EM propagations (for target tracking and countermeasure scenarios) through hot plumes, which require details of the temperature variance;
(3) rotorcraft/VSTOL plumes, which have strong vortical interactions and require non-linear EASM, and plume impingement problems that current turbulence models cannot accurately represent.

All these additional applications can be addressed by implementing the new turbulence framework into our present, specialized jet/plume commercial code.

NAME AND ADDRESS OF PRINCIPAL INVESTIGATOR (Name, Organization Name, Mail Address, City/State/Zip)
Donald C. Kenzakowski, Jr.
Combustion Research and Flow Technology, Inc.
174 North Main Street, P.O. Box 1150
Dublin , PA   18917 - 2108

NAME AND ADDRESS OF OFFEROR (Firm Name, Mail Address, City/State/Zip)
Combustion Research and Flow Tech., Inc.
174 North Main Street, P.O. Box 1150
Dublin , PA   18917 - 2108

Form Printed on 08-21-01 18:06