[aerosjc]

I use an in-house CFD code to simulate the flow over Idealized Side Mirror. The reference paper is Caraeni2011. To compare with the reference paper, I obtain the pressure history at the monitor points. By subtracting the mean of the pressure history, the fluctuation pressure is obtained.

Sound Pressure Level is defined as follows,



Now, my question is: is the fluctuation pressure the same as the sound pressure? Can I directly use my fluctuation pressure to calculate the SPL?

I know SPL is a single value and it requires Root Mean Square of the pressure history. What I want to calculate is actually the spectra of SPL. Just like the following pic. The unit of frequency is dB, and I guess it's typo.



In order to get the spectra of SPL, I apply FFT on the fluctuation pressure history and then feed the absolute value of the FFT result as input into the SPL formula to get the spectra of SPL.




[Caraeni2011]: Caraeni, M., Aybay, O., & Holst, S. (2011). Tandem Cylinder and Idealized Side Mirror Far-Field Noise Predictions Using DES and An Efficient Implementation of FW-H Equation. In 17th AIAA/CEAS Aeroacoustics Conference (32nd AIAA Aeroacoustics Conference) (pp. 5–8). Reston, Virigina: American Institute of Aeronautics and Astronautics. https://doi.org/10.2514/6.2011-2843