Multipolar viscous fluids

Faraday’s Instability for Viscous Fluids

We derive an exact equation which is nonlocal in time for the linear evolution of the surface of a viscous fluid, and show that this equation becomes local and of second order in an interesting limit. We use our local equation to study Faraday’s instability in a strongly dissipative regime and find a new scenario which is the analog of the Rayleigh-Taylor instability. Analytic and numerical cal...

Transport in Viscous Rotating Fluids

We consider a uniformly rotating viscous incompressible fluid and estimate particle transport in the vertical direction (parallel to the rotation axis). We prove that for short time and regular initial data, strong rotation suppresses the vertical gradient of flow maps. The proof uses a diffusive Lagrangian formalism, and the suppression of the vertical gradient is a natural and direct byproduc...

Potential Flow of Viscous Fluids: Historical Notes

A purely irrotational theory of the effect of viscosity on the decay of free gravity waves is derived and shown to be in excellent agreement with Lamb’s (1932) exact solution. The agreement is achieved for all waves numbers k excluding a small interval around a critical k=kc where progressive waves change to monotonic decay. Very detailed comparisons are made between the purely irrotational and...

Microcantilever mechanics in flowing viscous fluids

Implicit Formulation for SPH-based Viscous Fluids

We propose a stable and efficient particle-based method for simulating highly viscous fluids that can generate coiling and buckling phenomena and handle variable viscosity. In contrast to previous methods that use explicit integration, our method uses an implicit formulation to improve the robustness of viscosity integration, therefore enabling use of larger time steps and higher viscosities. W...