From the South Pole, microthermal turbulence within a narrow surface boundary layer some 200 m thick provides the dominant contribution to the astronomical seeing. We present results for the seeing at a wavelength of 2.4µm. The narrow turbulence layer above the site, confined close to the surface, provides greatly superior conditions for adaptive optics correction than do temperate latitude sit...

We define turbulent-turbulent spot as a local concentration of vortices with high level of swirling strength originating from hairpin packet in a turbulent boundary layer. We also define bypass transition in the narrow sense as the breakdown of the Blasius boundary layer beneath freestream homogeneous isotropic turbulence with an initial amplitude of 1 to 4 percent. We present evidence for the ...

This study investigates the role of topography-induced turbulence, generated by an idealized urban region, in transport firebrands and risk spotting. Flight dispersion, deposition, smoldering state tens thousands individual mass size-changing were investigated atmospheric boundary layer which was obtained using Large-eddy simulations. Firebrands assumed to be spherical particles Stokes numbers ...

This paper extends previous large-eddy simulations of the convective boundary layer over a surface with a spatially varying sensible heat flux. The heat flux variations are sinusoidal and onedimensional. The wavelength is 1500 or 4500 m (corresponding to 1.3 and 3.8 times the boundarylayer depth. respectively) and the wind speed is 0. 1 or 2 m sI. In every case the heat flux variation drives a ...

Eddy-resolved simulation of external flow usually requires inflow boundary conditions representing a turbulent layer (TBL) flow, and the quality fluctuation directly impact accuracy cost simulation. The present study proposes new method to generate TBL turbulence, i.e., equivalent (EBL) model. Based on open-channel model, EBL approximates at given Reynolds number by recovering mean momentum bal...