A Note on Equilibrium Turbulent Boundary Layer Wall Pressure Models

Turbulent boundary layers are a significant source of vibration and noise for vehicles moving through a fluid medium. Describing the forcing function for this noise source is an active area of research. Empirical models are commonly used in system noise models. Two common models as discussed by Mellen [1, 2] are separable and non-separable models. The separable models are in a class generally known as Corcos models [3]. The separable models postulate that the wall pressure space time statistics are a function of time times a function of downstream separation times a function of cross stream separation. The non-separable models postulate that the space time statistics are a function of time times a function of space with the downstream and cross stream separation being coupled. Two examples of the non-separable models are Chase [4, 5] and Smol'yakov-Tkachenko [6].

These models were used to compare to existing data from the MIT Low-Noise/Low-Turbulence Wind Tunnel as reported by Martini [7]. Martini made an effort to make low wavenumber measurements using both microphone arrays and plate structures similar to Martin [8] and Jameson [9]. The performance of the separable and non-separable models are compared and contrasted.