Non-isothermal turbulent flows in an enclosed rotorstator cavity are here investigated using large eddy simulation (LES). Besides their fundamental importance as three-dimensional prototype flows, such flows arise in many industrial applications and especially in turbomachineries. The LES is performed using a Spectral Vanishing Viscosity technique, which is shown leading to stable discretizations without sacrificing the formal accuracy of the spectral approximation. The LES results have been favorably compared to velocity measurements in the isothermal case. The Boussinesq approximation is then used to take into account the centrifugal-buoyancy effects. The thermal effects have been examined for Re equal to 1 million in a rotor-stator cavity of aspect ratio G=(b-a)/h=5 and curvature parameter Rm=(b-a)/(b+a)=1.8 (a, b the inner and outer radii of the rotor and h the interdisk spacing) and for Rayleigh numbers up to Ra=108. These LES results provide accurate, instantaneous quantities which are of interest in understanding the physics of turbulent flows and heat transfers in an interdisk cavity. The averaged results show small effects of density variation on the mean and turbulent fields.