I have acoustic pressure fluctuations from Ansys Fluent LES. I understand that Prms with required multiplications give OASPL directly. Fluent also does the same when we do acoustic analysis.
Integrating SPL with frequency gives me a 10 dB lesser value than the OASPL calc based on Prms. Why is this difference?
In short, anybody can help me how to get OASPL (dB) from PSD data of pressure signals ?
Hello all
Following are the answers to my own question.
1. From pressure fluctuations, we can get OASPL by 20*log10(Prms/Pref) ; Prms is in Pa.
2. We calculate Power spectral density of pressure signals, which is denoted by Spp ; (Pa^2/Hz).
Let 'df' be the frequency interval associated with the psd conversion.
OASPL can be obtained from psd data.
ie, OASPL = 10*log10(df*sum(Spp)/Pref^2). ; df*Spp ; unit is Pa^2.
3. Both methods shall be used to calculate OASPL and both methods should give you same OASPL (dB). This can be used as a cross check.
4.I was getting lower OASPL value because I missed out multiplication with 'df'.
- Badges
- Science topic