The response of small-scale shear layers to perturbations in turbulence cs
The response of small-scale shear layers to perturbations in turbulence T. Watanabe and K. Nagata Journal of Fluid Mechanics, 963 A31 2023 (Open Access) This article may be found at https://doi.org/10.1017/jfm.2023.316. The article is also available here . Abstract The perturbation response of small-scale shear layers in turbulence is investigated with direct numerical simulations (DNS). The analysis of shear layers in isotropic turbulence suggests that the typical layer thickness is about four times the Kolmogorov scale η. Response for sinusoidal perturbations is investigated for an isolated shear layer, which models a mean flow around the shear layers in turbulence. The vortex formation in the shear layer is optimally promoted by the perturbation whose wavelength divided by the layer thickness is about 7. These results indicate that the small-scale shear instability in turbulence is efficiently promoted by velocity fluctuations with a wavelength of about 30η. Furthermore, DNS