Numerical Methods for PDEs: High-Order Schemes, Geometric Integrators, and Non-Euclidean Operators

Report on Current Developments in the Research Area

General Direction of the Field

The recent advancements in the research area predominantly revolve around the development and refinement of numerical methods for solving partial differential equations (PDEs) on complex geometries and under various constraints. The field is witnessing a shift towards higher-order accuracy, stability, and adaptability in numerical schemes, driven by the need to handle increasingly intricate problems in science and engineering.

One of the key trends is the extension of high-order finite-difference operators to non-conforming and complex geometries, leveraging point clouds and adaptive meshing techniques. This approach allows for more flexible and efficient discretizations, particularly in scenarios where traditional mesh-based methods fall short. The integration of summation-by-parts (SBP) properties with point-cloud methods is a notable innovation, enhancing both the stability and accuracy of the numerical solutions.

Another significant development is the application of advanced time-stepping methods, such as the $hp$-discontinuous Galerkin (DG) method, to nonlinear and memory-dependent PDEs. These methods are proving to be highly effective in achieving optimal convergence rates and maintaining stability, even in the presence of weakly singular kernels. The combination of high-order spatial discretizations with sophisticated time-stepping techniques is a promising direction for tackling complex, multi-scale problems.

The field is also seeing a growing interest in the development of geometric integrators for non-Hamiltonian systems, particularly those governed by Poisson structures. This includes the exploration of symplectic realizations and the construction of Poisson integrators, which aim to preserve the geometric properties of the underlying manifolds. These methods are crucial for maintaining long-term stability and accuracy in simulations of dynamical systems.

Additionally, there is a focus on the development of discrete Laplacians and other differential operators on non-Euclidean spaces, such as hyperbolic geometries. These efforts are aimed at bridging the gap between continuous and discrete formulations of PDEs on Riemannian manifolds, with a particular emphasis on stability and convergence properties.

Noteworthy Papers

  • High-order finite-difference operators on point clouds: The development of SBP operators on point clouds over complex geometries is a significant advancement, offering a flexible and stable alternative to traditional mesh-based methods.

  • $hp$-discontinuous Galerkin method for generalized Burgers-Huxley equation: The application of $hp$-DG time-stepping to nonlinear advection-diffusion-reaction problems with memory is noteworthy for its optimal convergence and stability properties.

  • Geometric integrators for Poisson manifolds: The proposed framework for constructing Poisson integrators based on symplectic realizations is a groundbreaking approach, addressing the challenges of singular and nonlinear Poisson structures.

Sources

Constructing stable, high-order finite-difference operators on point clouds over complex geometries

hp-discontinuous Galerkin method for the generalized Burgers-Huxley equation with weakly singular kernels

Nonlinear Schwarz methods to compute geodesics on manifolds

Fourth-order compact finite difference schemes for solving biharmonic equations with Dirichlet boundary conditions

Discrete Laplacians on the hyperbolic space -- a compared study

A Parareal algorithm without Coarse Propagator?

Derivation of normal forms for dispersive PDEs via arborification

Approximating Symplectic Realizations: A General Framework for the Construction of Poisson Integrators