Abstract
To assess the efficacy of different non-reflecting boundary conditions (NRBCs) in high-order compressible flow solvers, several NRBCs have been implemented and studied in the context of the discontinuous Galerkin (DG-)finite element method (FEM) discretization. The methods considered are based on buffer zone techniques and boundary-imposed conditions. The boundary-imposed methods are mainly a standard Riemann-extrapolation technique and a novel reconstruction that imposes the Navier-Stokes characteristic boundary condition (NSCBC). The buffer zone strategies considered utilize the sponge layer (SL), the perfectly matched layer (PML), the supersonic layer (SSL) and a novel characteristic matching layer (CML).
The reconstruction, termed as a polynomial-correction (PC), assembles an explicit boundary state, needed by the numerical fluxes (inviscid and viscous) of the DG-FEM, by taking the standard NSCBC methodology into account. The CML uses characteristic theory to enforce a non-reflective behavior over an entire layer, by eliminating or "matching" incoming reflections into the physical domain.
Tests have been done on several problems, ranging from 1D to 3D, using (non-linear) Euler and Navier-Stokes equations, on academic and industrial test-cases. The proposed methods, PC-NSCBC and CML, demonstrate how effective they are when compared to a standard Riemann extrapolation, as well as other NRBCs.
The reconstruction, termed as a polynomial-correction (PC), assembles an explicit boundary state, needed by the numerical fluxes (inviscid and viscous) of the DG-FEM, by taking the standard NSCBC methodology into account. The CML uses characteristic theory to enforce a non-reflective behavior over an entire layer, by eliminating or "matching" incoming reflections into the physical domain.
Tests have been done on several problems, ranging from 1D to 3D, using (non-linear) Euler and Navier-Stokes equations, on academic and industrial test-cases. The proposed methods, PC-NSCBC and CML, demonstrate how effective they are when compared to a standard Riemann extrapolation, as well as other NRBCs.
Original language | English |
---|---|
Qualification | Doctor of Philosophy |
Awarding Institution |
|
Supervisors/Advisors |
|
Award date | 13 May 2024 |
Place of Publication | Enschede |
Publisher | |
Print ISBNs | 978-90-365-6092-4 |
Electronic ISBNs | 978-90-365-6093-1 |
DOIs | |
Publication status | Published - 13 May 2024 |
Keywords
- Computational Fluid Dynamic (CFD)
- perfectly matched layers
- Navier-Stokes Characteristic Boundary Conditions
- Discontinuous Galerkin finite element method
- High-order methods
- Non-reflecting boundary conditions
- Navier-Stokes equations
- Euler equations