Pressure Fluctuations in a High-Reynolds-Number Turbulent Boundary Layer Flow over Rough Surfaces

Boundary layer flow interaction with a permeable wall

“…As reviewed above, despite a large body of the literature on the interaction of flow on rough permeable surfaces, there are only a few studies on the pressure fluctuations for boundary layers over rough [26][27][28][29] and porous 5 surfaces, which are of great importance for understanding the noise and vibration generation from such structures. Blake 26 studied the pressure fluctuations for turbulent boundary layers over smooth and different rough walls.…”

“…It was also confirmed that the friction velocity obtained in the case of rough-wall boundary layers is always less than the conventional friction velocity found for a smooth-wall boundary layer and confirmed that the boundary layer parameters and the wall pressure spectrum are nearly independent of the surface roughness for the conditions considered in the study. Building on the work of Meyers, Joseph et al 29 have investigated rough walls with two fetches of hemispherical roughness elements with two different spacing ratios. It has been demonstrated that the pressure spectral shape changes at mid frequencies with the roughness density, and it was speculated that the spectral changes are not due to the changes in the turbulence structure but rather due to the displacement of the pressure fluctuations over the roughness elements.…”

Characteristics of the pressure fluctuations generated in turbulent boundary layers over rough surfaces

“…The experimental arrangement was replicated from the work of Meyers et al. (2015) and is further detailed by Joseph (2017). The test section, with coordinate system, is presented in figure 1.…”

“…The complete specifications of the CTA module and NI-9239 cDAQ modules used for data acquisition are detailed by Joseph (2017). Quadwire data were validated by a Auspex AHWU-100 constant-temperature single hot-wire probe and a flattened Pitot probe, which are also fully described by Joseph (2017). These two probes were similarly arranged in tandem to acquire data simultaneously, as shown in figure 6( b ).…”

“…(1992) found that smooth- and rough-wall turbulent boundary layers show deviations over a significant portion of the layer, not just within the near-wall region. Most recently, the experiments of Joseph (2017) did not show proof of wall similarity, despite exceeding both qualifying criteria.…”