Taylor-Couette Instability in General Manifolds: A Lattice Kinetic Approach

We present a new lattice kinetic method to simulate fluid dynamics in curvilinear geometries. A suitable discrete Boltzmann equation is solved in contravariant coordinates, and the equilibrium distribution function is obtained by a Hermite polynomials expansion of the Maxwell-Boltzmann distribution, expressed in terms of the contravariant coordinates and the metric tensor. To validate the model, we calculate the critical Reynolds number for the onset of the Taylor-Couette instability between two concentric cylinders, obtaining excellent agreement with the theory. In order to extend this study to more general geometries, we also calculate the critical Reynolds number for the case of two concentric spheres, finding good agreement with experimental data. In the case of two concentric tori, we have found that the critical Reynolds is about 10% larger than the respective value for the two concentric cylinders.