Statistical behavior of UMZs and shear layers under an FPG

Uniform momentum zones are large scale regions of uniform momentum which have been an area of interest in the field of turbulent boundary layers for the past few decades. These regions are bounded by regions of high localized shear called shear layers. The behavior of these structures is understood well in ZPGs. This talk discusses the behavior of UMZs and shear layers in a spatially varying FPG (Agrawal & Saxton-Fox, SCITECH 2025). The talk will focus on how the number, strength, and thickness of shear layers and UMZs vary with pressure gradient. PIV data collected at a friction Reynolds number of approximately 950 under 3 different rapidly varying FPGs (and a ZPG) will be used to inform this analysis. A novel histogram characterization analysis will be used to analyze the strength and thickness of shear layers and UMZs. The talk will discuss the reduction in turbulence production in FPGs and its correlation with regions of high shear.