Preferential spectral transport by irrotational straining

The addition of an extra term to the conventional approximate transport equation for the turbulence energy dissipation rate is recommended. The term may be viewed as emphasizing the role of irrotational deformations in promoting energy transfer across the spectrum or, equivalently, as augmenting the influence of normal strains. Calculations including the new term are reported for the plane and round jet and for several turbulent boundary layers. In the cases considered the addition of the new term significantly improves agreement with experimental data.