Abstract
The dimensionless dissipation coefficient β=εL/U3, whereεis the dissipation rate, U the rootmeansquare velocity andLthe characteristic scale of the largest flow structures, isan important characteristic of statistically stationary homogeneous turbulence. In studies of β, the external force is typically isotropic and large scale, and its helicity Hf either zero or not measured. Here, we study the dependence of β on Hf and find that it decreases β by up to 10% for both isotropic forces and shear flows. The numerical finding is supportedby static and dynamical upper bound theory. Both show a relative reduction similar tothe numerical results. That is, the qualitative and quantitative dependence ofβon thehelicity of the force is well captured by upper bound theory. Consequences for the valueof the Kolmogorov constant and theoretical aspects of turbulence control and modellingare discussed in connection with the properties of the external force. In particular, the eddy viscosity in large eddysimulations of homogeneous turbulence should be decreased by at least 10% in the case of strongly helical forcing.
Original language  English 

Pages (fromto)  79102 
Number of pages  24 
Journal  Journal of Fluid Mechanics 
Volume  856 
Early online date  28 Sep 2018 
DOIs  
Publication status  Published  10 Dec 2018 
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Moritz Linkmann
 School of Mathematics  Lectureship/Readership in Applied and Computational Mathemat
Person: Academic: Research Active (Teaching)