Modelling of conventionally neutral boundary layers with an explicit algebraic Reynolds stress model

An explicit algebraic Reynolds stress model (EARSM) is tested for the simulation of conventionally neutral boundary layers (CNBLs) with varying capping inversion strengths. Good agreement of first- and second-order statistics with reference large-eddy simulations (LESs) are obtained, and the model is also able to capture anisotropy of velocity variances and non-zero horizontal heat fluxes, which cannot be predicted with traditional eddy-viscosity models (EVMs). No further tuning was made to the EARSM, which demonstrates its generality. Some deviations between the EARSM and LES were observed for the horizontal heat fluxes and the half temperature variance in the capping inversion layer, and a detailed budget analysis of the latter revealed that this is related to the modelling of the half temperature variance dissipation.