We present the Moving Eulerian-Lagrangian Particles (MELP), a novel mesh-free method for simulating incompressible fluid on thin films and foams. Employing a bi-layer particle structure, MELP jointly simulates detailed, vigorous flow and large surface deformation at high stability and efficiency. In addition, we design multi-MELP: a mechanism that facilitates the physically-based interaction between multiple MELP systems, to simulate bubble clusters and foams with non-manifold topological evolution. We showcase the efficacy of our method with a broad range of challenging thin film phenomena, including the Rayleigh-Taylor instability across double-bubbles, foam fragmentation with rim surface tension, recovery of the Plateau borders, Newton black films, as well as cyclones on bubble clusters.

We propose a particle-based method to simulate thin-film fluid that jointly facilitates aggressive surface deformation and vigorous tangential flows. We build our dynamics model from the surface tension driven Navier-Stokes equation with the dimensionality reduced using the asymptotic lubrication theory and customize a set of differential operators based on the weakly compressible Smoothed Particle Hydrodynamics (SPH) for evolving pointset surfaces. The key insight is that the compressible nature of SPH, which is unfavorable in its typical usage, is helpful in our application to co-evolve the thickness, calculate the surface tension, and enforce the fluid incompressibility on a thin film. In this way, we are able to two-way couple the surface deformation with the in-plane flows in a physically based manner. We can simulate complex vortical swirls, fingering effects due to Rayleigh-Taylor instability, capillary waves, Newton's interference fringes, and the Marangoni effect on liberally deforming surfaces by presenting both realistic visual results and numerical validations. The particle-based nature of our system also enables it to conveniently handle topology changes and codimension transitions, allowing us to marry the thin-film simulation with a wide gamut of 3D phenomena, such as pinch-off of unstable catenoids, dripping under gravity, merging of droplets, as well as bubble rupture.

Software-defined networking (SDN) is an emerging network architecture and OpenFlow is one of the representative works in SDN. As a possible approach towards future network, it has been introduced into a lot of application scenarios. Although SDN/OpenFlow have a lot of advantages, it is still debatable that whether they can manipulate a significant amount of real-life traffic when they are deployed in a large-scale ISP (Internet Service Provider) network. However, there are few studies of performance evaluation of SDN/OpenFlow system with real-life traffic. In this paper we present OFSim, an event-driven OpenFlow simulator that supports the performance evaluation of OpenFlow system with packet-level real-life traffic traces. We use OFSim to perform evaluations with real-life ISP traffic and experimental results show that: (i) Current OpenFlow switch implementations cannot meet the need of real-life ISP traffic; (ii) Although the issue of controller scalability exists, greater performance bottleneck may be located in the current OpenFlow switches, and the flow table entry installation delay is a more pressing issue. This study can be helpful to better understand the performance bottleneck of OpenFlow system under the scenario in an ISP network.