Abstract We propose a volume fraction based approach to effectively simulate the miscible and immiscible flows simultaneously. In this method, a volume fraction is introduced for each fluid component and the mutual interactions between different fluids are simulated by tracking the evolution of the volume fractions. Different techniques are employed to handle the miscible and immiscible interactions and special treatments are introduced to handle flows involving multiple fluids and different kinds of interactions at the same time. With this method, second‐order accuracy is preserved in both space and time. The experiment results show that the proposed method can well handle both immiscible and miscible interactions between fluids and much richer mixing detail can be generated. Also, the method shows good controllability. Different mixing effects can be obtained by adjusting the dynamic viscosities and diffusion coefficients. Copyright © 2010 John Wiley & Sons, Ltd.

We present a particle-based method for viscoelastic fluids simulation. In the method, based on the traditional Navier-Stokes equation, an additional elastic stress term is introduced to achieve viscoelastic flow behaviors, which have both fluid and solid features. Benefiting from the Lagrangian nature of Smoothed Particle Hydrodynamics, large flow deformation can be handled more easily and naturally. And also, by changing the viscosity and elastic stress coefficient of the particles according to the temperature variation, the melting and flowing phenomena, such as lava flow and wax melting, are achieved. The temperature evolution is determined with the heat diffusion equation. The method is effective and efficient, and has good controllability. Different kinds of viscoelastic fluid behaviors can be obtained easily by adjusting the very few experimental parameters.

Abstract We present a novel pressure correction scheme for the Smoothed Particle Hydrodynamics (SPH) for fluid animation. In the conventional SPH method, equations of state (EOS) are employed to relate the pressure to the particle density. To enforce the volume conservation, high speeds of sound are usually required, which leads to very small time steps and noisy pressure distribution. The problem remains one of the main reasons of numerical instability in SPH. In the paper, a new extra pressure correction scheme is proposed to transport the local pressure disturbance to the neighboring area and no solution of the Poisson equation is required. As a result, smoother pressure distribution and more efficient simulation are achieved. The proposed method has been used to simulate free surface problems. The results demonstrate the validation of the present SPH method. Surface tension and fluid fragmentation can be well handled. Copyright © 2009 John Wiley & Sons, Ltd.

In our surrounding environment, we may often see many various miscible liquid-liquid mixture phenomena, like pouring honey or ink into water, Coca Cola into strong wine etc., while few papers have devoted to the simulation of the phenomena. In this paper, we use a two-fluid lattice Boltzmann method (TFLBM) to simulate the underlying dynamics of miscible mixtures. By the method, a subgrid model is applied to improve its numerical stability so that the free surface of the mixture, accompanying with higher Reynolds number, can be simulated. We also apply control forces to the mixture with interesting animation created. By optimizing the memory structure and taking the advantage of dual-core or multi-core systems, we achieve real time computation for a domain in 643 cells full of fluid mixtures.

An embedded image compression scheme using the discrete multiwavelet transform (DMWT) is proposed. The proposed coding scheme is based on a new prefilter design for DMWT and a new embedded coding algorithm which combines scalar quantization and 2/spl times/2 vector quantization (VQ). A new algorithm for embedded VQ codebook generation is proposed, which is shown to have a better performance than the current schemes. The performance of the proposed compression scheme is comparable to the one of the SPIHT algorithm.