On the Lundgren–Townsend model of turbulent fine scales

D. I. Pullin, P. G. Saffman
1993 Physics of Fluids A Fluid Dynamics  
The strained-spiral vortex model of turbulent fines scales given by Lundgren [Phys. Fluids 25, 2193 ( 1982 ] is used to calculate vorticity and velocity-derivative moments for homogeneous isotropic turbulence. A specific form of the relaxing spiral vortex is proposed modeled by a rolling-up vortex layer embedded in a background containing opposite signed vorticity and with zero total circulation at infinity. The numerical values of two dimensionless groups are fixed in order to give a
more » ... constant and skewness which are within the range of experiment. This gives the result that the ratio of the ensemble average hyperskewness S'++ t = (au/&c) QJ+ '/[(&/ax) 2](2P+ 1)'2 to the hyperflatness F2p'(d~/d~)'P/[(d~/d~)2] P, p=2,3,.
doi:10.1063/1.858798 fatcat:kydnpqjom5eunpmvr3iya3n5gm