The Spectral Shape of Flow Noise, Turbulence and Wall Pressure Fluctuations and Interrelation.
Abstract
An elementary model of how a turbulent boundary layer (b.l.) generates noise is analyzed. Two similarity hypotheses are given which relate b.l. turbulence to flow noise. Dynamic pressures come from the forces created by the interaction of eddies on the viscous sublayer where velocity components normal to the wall are brought to rest; and The forces are proportional to the second power of the eddy velocities and the distribution of separation distance between pressure points on the wall is the same as the distribution of eddy sizes. It is concluded that flow noise, wall pressure fluctuations and b.l. turbulence all have the same spectral shape in frequency space. Data on wall pressures fluctuations generally have a f to the -11/3 power form due to spatial averaging by the pressure sensor. Corrections for pressure sensor averaging are given and experimental data is given to demonstrate the validity of the correction.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 16, 1978
- Accession Number
- ADA056291
Entities
People
- J. P. Clay
Organizations
- Pennsylvania State University