NASA's Glenn Research Center has laid out its toolbox of engine-noise prediction software, and engineers can request copies through NASA's Software Catalog. The codes help designers estimate how loud a new jet or fan will be before anyone builds hardware.
The page is a catalog, not a launch announcement, and it gives no release date or new version number. We can only describe what NASA says the tools do.
Jet noise: JeNo and MGBK
JeNo predicts the far-field sound from axisymmetric (round, symmetrical) jets at an observer position and frequency range the user picks. NASA says it has been validated for subsonic and low supersonic jets that are unheated. It rests on Lilley's Acoustic Analogy plus airflow solutions from a RANS code, a fast type of fluid simulation. NASA notes that this approach gives quicker answers than Large-Eddy Simulation or Direct Numerical Simulation, so the quality of the airflow prediction decides the quality of the noise prediction.
MGBK came before JeNo. Glenn researchers used it to predict noise trends for complicated exhaust nozzles, including the chevrons, the serrated edges seen on many airliner engines today.
Fan noise: from quick estimates to 3-D
V072 uses simple fan models to study the tone noise from rotor and stator interaction. NASA says it can guide choices such as blade and vane counts, spacing, and stator sweep and lean. TFaNS goes further, accounting for how sound is transmitted and reflected between blade rows and carrying the tones to the far field. Like V072, it runs quickly and suits early design.
When those are too simple, Linflux handles realistic 3-D flows and blade shapes, at a much higher computing cost. BFANS covers broadband noise from turbulence hitting blade and vane edges. NASA says paired with wind tunnel data, such as from Glenn's 9 by 15 foot Low Speed Wind Tunnel, it can help find the noisiest parts of a fan stage.
NASA says all software from the Glenn Acoustics Branch has been rigorously validated against experimental data. That is the agency's own claim, and we have not seen the validation results.
What to watch
Do you think quieter engines will come from better software or from better hardware?
Sources
- 1.Software - NASA · NASA
Reported by the WattsUpNext desk from the sources linked below. Spot an error? Tell us at corrections@wattsupnext.com.
The WattsUpNext Brief
Get stories like this in your inbox.
One email each weekday, only the topics you choose. Real news, sourced, no fluff. Unsubscribe in one click.
