Communications on Applied Mathematics and Computation ›› 2024, Vol. 6 ›› Issue (4): 2155-2195.doi: 10.1007/s42967-023-00325-2

• ORIGINAL PAPERS • 上一篇    下一篇

Dispersion in Shallow Moment Equations

Ullika Scholz1, Julia Kowalski2, Manuel Torrilhon1   

  1. 1 Applied and Computational Mathematics (ACoM), RWTH Aachen University, Aachen, Germany;
    2 Methods for Model-based Development in Computational Engineering (MBD), RWTH Aachen University, Aachen, Germany
  • 收稿日期:2023-05-07 修回日期:2023-09-08 接受日期:2023-09-10 发布日期:2024-12-20
  • 通讯作者: Ullika Scholz,E-mail:scholz@acom.rwth-aachen.de E-mail:scholz@acom.rwth-aachen.de
  • 基金资助:
    Open Access funding enabled and organized by Projekt DEAL.

Dispersion in Shallow Moment Equations

Ullika Scholz1, Julia Kowalski2, Manuel Torrilhon1   

  1. 1 Applied and Computational Mathematics (ACoM), RWTH Aachen University, Aachen, Germany;
    2 Methods for Model-based Development in Computational Engineering (MBD), RWTH Aachen University, Aachen, Germany
  • Received:2023-05-07 Revised:2023-09-08 Accepted:2023-09-10 Published:2024-12-20
  • Contact: Ullika Scholz,E-mail:scholz@acom.rwth-aachen.de E-mail:scholz@acom.rwth-aachen.de
  • Supported by:
    This research is in part supported by the NSF Grants DMS-1912654 and DMS 2205590.

摘要: Shallow moment models are extensions of the hyperbolic shallow water equations. They admit variations in the vertical profile of the horizontal velocity. This paper introduces a non-hydrostatic pressure to this framework and shows the systematic derivation of dimensionally reduced dispersive equation systems which still hold information on the vertical profiles of the flow variables. The derivation from a set of balance laws is based on a splitting of the pressure followed by a same-degree polynomial expansion of the velocity and pressure fields in a vertical direction. Dimensional reduction is done via Galerkin projections with weak enforcement of the boundary conditions at the bottom and at the free surface. The resulting equation systems of order zero and one are presented in linear and nonlinear forms for Legendre basis functions and an analysis of dispersive properties is given. A numerical experiment shows convergence towards the resolved reference model in the linear stationary case and demonstrates the reconstruction of vertical profiles.

关键词: Shallow flow, Free surface flow, Non-hydrostatic model, Dispersive equations, Moment approximation, Hyperbolic systems

Abstract: Shallow moment models are extensions of the hyperbolic shallow water equations. They admit variations in the vertical profile of the horizontal velocity. This paper introduces a non-hydrostatic pressure to this framework and shows the systematic derivation of dimensionally reduced dispersive equation systems which still hold information on the vertical profiles of the flow variables. The derivation from a set of balance laws is based on a splitting of the pressure followed by a same-degree polynomial expansion of the velocity and pressure fields in a vertical direction. Dimensional reduction is done via Galerkin projections with weak enforcement of the boundary conditions at the bottom and at the free surface. The resulting equation systems of order zero and one are presented in linear and nonlinear forms for Legendre basis functions and an analysis of dispersive properties is given. A numerical experiment shows convergence towards the resolved reference model in the linear stationary case and demonstrates the reconstruction of vertical profiles.

Key words: Shallow flow, Free surface flow, Non-hydrostatic model, Dispersive equations, Moment approximation, Hyperbolic systems