On the different contributions of coherent structures to the spectra of a turbulent round jet and a turbulent boundary layer. (English) Zbl 0995.76033

Nickels, T. B.; Marusic, Ivan

J. Fluid Mech. 448, 367-385 (2001).

Summary: This paper examines and compares spectral measurements for a turbulent round jet and for a turbulent boundary layer. The conjecture that is examined is that both flows consist of coherent structures immersed in a background of isotropic turbulence. In the case of jet, a single size of coherent structure is considered, whereas in the boundary layer there are a range of sizes of geometrically similar structures. The conjecture is examined by comparing experimental measurements of spectra for the two flows with the spectra calculated using models based on simple vortex structures. The universality of small scales is considered by comparing high-wavenumber experimental spectra. It is shown that these simple structural models give a good account of the turbulent flows.

MSC:

76F40	Turbulent boundary layers
76-05	Experimental work for problems pertaining to fluid mechanics

Keywords:

turbulent round jet; turbulent boundary layer; coherent structures; high-wavenumber experimental spectra