Assessment of anisotropy in the decay term of the dissipation equation for Reynolds stress transport models*

In a recent study, Homan et al. (DFD-A43.00005, 2023) showed that states of turbulence anisotropy can be accessed in a triply periodic domain using the volumetric forcing scheme of Dhandapani et al. 2019. Using their simulation data, they proposed a new model for the decay terms of the Reynolds stress transport (RST) equations. However, their model assumes the kinetic energy dissipation rate as a given time resolved quantity. In this study, we build on the same methodology by examining the decay rate of the dissipation field itself. For homogeneous flows and in the absence of mean velocity gradients, dissipation decay is the only active closure. Based on our assessment, we identify anisotropies that should be included in the dissipation decay under such conditions.