The empirical data is from multiple flow velocities, pipe diameters, and noise sources. The noise sources investigated include mitered bends, radius bends, straight pipes, valves, and tees. The method is only applicable to steel pipes and gas flow.
Data from tests was converted to non-dimensional curves representing the internal pressure spectrum and converted to strouhal numbers and wall pressure spectra – see Figure 4-2 below. The Strouhal number is calculated using pipe diameter and internal flow speed, using the measured response frequency, based