AbstractA description is given of a numerical model which has been used to simulate the steady baroclinic waves which may be observed in a fluid rotating about a vertical axis and subjected to a radial temperature gradient. the model is designed to provide accurate simulations of the observed flow without recourse to parametrization of small eddies. the model is verified by comparing the results of integrations with observed flows; many of the differences between the simulated and observed flows may be ascribed to the limited resolution of the model. the numerical model is used to provide data on the non‐linear interactions between different scales of motion present in the steady flows. It is demonstrated that the predominant non‐linear interaction, in the numerical model, involving the sidebands of the dominant wave is an interaction with the first harmonic of the dominant wave; this contrasts with an interaction with the long wave which was suggested by earlier workers. Experimental evidence is advanced to show that the sidebands may be enhanced by weak asymmetrical forcing and this sensitivity has been verified through the results the further numerical integrati