On new hyperbolic moment models for the Boltzmann equation

The Boltzmann equation can be used to model flows in the transition or kinetic regime. However,standard moment methods like Grad’s approach lack hyperbolicity. Based on recent developments in this field, we have derived a quadrature-based moment method leading to globally hyperbolic and rotationally invariant moment equations. The method is presented as one example of a newly developed operator projection framework. We discuss a special case of the model equations and compare the new model to standard models by analyzing the structure of the equations.