论文标题
功能化的Cahn-Hilliard梯度流中形态复杂性的基准计算
Benchmark Computation of Morphological Complexity in the Functionalized Cahn-Hilliard Gradient Flow
论文作者
论文摘要
溶剂中两亲分子的自洽平均野外理论模型的减少会导致一个唯一的功能化Cahn-Hilliard能量家族。我们修改了这些能量,使奇异性稳定以稳定梯度流的计算,并产生一系列基准问题,这些问题模仿实验中观察到的“形态复杂性”。这些基准测试了两亲材料吸收速率与界面上的最小能量机制之间的微妙平衡。结果是反应的三分法,其中二维界面通过针对曲率的正规运动延长,进行珍珠分叉或直接分成界面网络。我们评估了许多使用二阶BDF2型时间步进的方案,并结合傅立叶伪空间空间离散化。 BDF2型方案基于PSD非线性求解器的完全隐式时间离散化,或者是基于IMEX,SAV,ETD的方法。所有方案都使用固定的本地截断误差目标,并使用自适应时间步进来实现误差目标。每个方案都需要适当的“预处理”以实现可靠的性能,从而可以通过几个数量级提高效率。
Reductions of the self-consistent mean field theory model of amphiphilic molecules in solvent can lead to a singular family of functionalized Cahn-Hilliard energies. We modify these energies, mollifying the singularities to stabilize the computation of the gradient flows and develop a series of benchmark problems that emulate the "morphological complexity" observed in experiments. These benchmarks investigate the delicate balance between the rate of absorption of amphiphilic material onto an interface and a least energy mechanism to disperse the arriving mass. The result is a trichotomy of responses in which two-dimensional interfaces either lengthen by a regularized motion against curvature, undergo pearling bifurcations, or split directly into networks of interfaces. We evaluate a number of schemes that use second order BDF2-type time stepping coupled with Fourier pseudo-spectral spatial discretization. The BDF2-type schemes are either based on a fully implicit time discretization with a PSD nonlinear solver, or upon IMEX, SAV, ETD approaches. All schemes use a fixed local truncation error target with adaptive time-stepping to achieve the error target. Each scheme requires proper "preconditioning" to achieve robust performance that can enhance efficiency by several orders of magnitude.