A sheet of porous material is suspended in air at a distance of 1/4 wavelength in front of a rigid wall. For the frequency of interest, the mass of sheet is high enough not to move significantly under the influence of a sound wave. When a constant frequency plane wave is normally incident on the sheet, a microphone behind it at the wall surface registers an rms value of 0.2 Pa.
What is the specific flow resistance of the sheet?
Vfront-Vsheet=Vback-Vsheet= (1/Rf) x (Pfront-Pback)
Pback=0.2 Pa (Given)
We need to find Rf=specific flow resistance.
The Attempt at a Solution
I think that Vsheet=0 since the pressure is not enough to move the sheet.
we dont know Pfront.