Loading...
Please wait, while we are loading the content...
Similar Documents
Broadband noise prediction when turbulence simulation is available - derivation of formulation 2b and its statistical analysis
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Farassat, Fereidoun Casper, Jay H. |
| Copyright Year | 2012 |
| Description | We show that a simple modification of Formulation 1 of Farassat results in a new analytic expression that is highly suitable for broadband noise prediction when extensive turbulence simulation is available. This result satisfies all the stringent requirements, such as permitting the use of the exact geometry and kinematics of the moving body, that we have set as our goal in the derivation of useful acoustic formulas for the prediction of rotating blade and airframe noise. We also derive a simple analytic expression for the autocorrelation of the acoustic pressure that is valid in the near and far fields. Our analysis is based on the time integral of the acoustic pressure that can easily be obtained at any resolution for any observer time interval and digitally analyzed for broadband noise prediction. We have named this result as Formulation 2B of Farassat. One significant consequence of Formulation 2B is the derivation of the acoustic velocity potential for the thickness and loading terms of the Ffowcs Williams-Hawkings (FW-H) equation. This will greatly enhance the usefulness of the Fast Scattering Code (FSC) by providing a high fidelity boundary condition input for scattering predictions. |
| File Size | 1397016 |
| Page Count | 10 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20120008645 |
| Archival Resource Key | ark:/13960/t9v171j6h |
| Language | English |
| Publisher Date | 2012-01-01 |
| Access Restriction | Open |
| Subject Keyword | Acoustics Turbulence Statistical Analysis Broadband Aerodynamic Noise Rotor Blades Rotor Dynamics Semiempirical Equations Numerical Analysis Ffowcs Williams-hawkings Equation Simulation Far Fields Near Fields Aeroacoustics Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
