Institute of Aerodynamics and Gas Dynamics
Tel.: +49 (0)711 685-60224
- Discontinuous Galerkin (DG) methods for compressible multiphase flows at extreme ambient conditions (e.g. at the critical point)
- Realistic equation of states for the description of multi-phase flows at sub- and super-critical conditions
- Resolution of interface related phenomena like surface tension and phase transition by generalized Riemann problems
- Project A2 (“Development of numerical methods for the simulation of compressible droplet dynamic processes at extreme ambient conditions”) within collaborative research council SFB-TRR75
- Direct numerical simulation
- High performance computing (HPC)
In many technical applications, multi-phase flows meet conditions such as high pressure environments and/or high velocities that prohibit the popular assumption of incompressibility. Important examples for such extreme ambient conditions include fuel injection systems of aeronautical, automotive and rocket engines that operate at high-pressure and/or high-temperature conditions. In contrast to the incompressible treatment, that is typically found in two-phase numerical solvers in practical use today, all conservation equations are coupled via the equation of state and have to be solved simultaneously. The decomposition and separate solution of hydrodynamics and thermodynamics as in the incompressible case is no longer possible. Hence, the numerical simulation of compressible multi-phase flow introduces additional difficulties to the numerical approach mainly due to the necessary consistent approximation of thermodynamics and the large density and pressure jumps.
In the last years the focus of the research was on the development of consistent numerical methods for the resolution of the phase interface in the computational domain. We focused on the sharp interface resolution of the interface. At the interface the jump conditions are provided by the solution of a generalized Riemann problem. This interface Riemann solution resolved local interface effects due to the coupling of different phases, surface tension and phase transition. Exact and approximative solvers have been developed for this case. For cases including phase transition effects this results in a mixed hyperbolic-elliptic problem. Hence, special considerations for the resolution of the interface Riemann problem have to be taken.
The numerical method is based on the discontinuous Galerkin spectral element method with a sub-cell finite volume refinement in the vicinity of the phase interface. This approach is done to enlarge the interface resolution that is implemented by means of generalized Riemann problems at the grid cell boundaries. The interface tracking is based on the level-set method extended for a compressible flow field. The high-order level-set descriptions mimics numerical diffusion problems and allows the accurate resolution of the interface curvature and normals. The accuracy of these quantities can be enlarged by a a-posteriori reconstruction of the level-set polynomial.
Simulation of compressible multi-phase flows at extreme ambient conditions (PhD defence) Presentation
Simulation of compressible multi-phase flows using a Discontinuous Galerkin Method and realistic equations of state Presentation
Interface coupling based on a Discontinuous Galerkin multi-scale method for compressible multiphase flow Presentation
Jeju, South Korea, 29.05.2013.
A discontinuous Galerkin based multiscale solver for compressible two-phase flows Presentation
A discontinuous Galerkin based multiscale method for compressible multiphase flow Presentation
International Journal of Numerical Methods in Fluids Journal for Numerical Methods in Fluids, 78 (7), pp. 413-435, 2015, ISSN: 1097-0363.
Simulation of compressible multi-phase flows at extreme ambient conditions using a Discontinuous Galerkin Method Inproceedings
Proceedings of the 26th Annual Conference on Liquid Atomization and Spray Systems (ILASS) 2014, Bremen, Germany, 2014.
A Combined Finite Volume Discontinuous Galerkin Approach for the Sharp-Interface Tracking in Multi-Phase Flow Incollection
Finite Volumes for Complex Applications VII-Elliptic, Parabolic and Hyperbolic Problems, pp. 911–918, Springer, 2014.
Interface coupling based on a Discontinuous Galerkin multi-scale method for compressible multiphase flow Inproceedings
Proceedings of the 8th International Conference on Multiphase Flow ICMF 2013, Jeju, Korea., 2013.
Exact and approximate Riemann solvers at phase boundaries Journal Article
Computers & Fluids, 75 (0), pp. 112-126, 2013, ISSN: 0045-7930.
Experimental and numerical investigation of narrow impingement cooling channels Journal Article
International Journal of Heat and Mass Transfer, 67 , pp. 1208–1219, 2013.
Direct numerical simulation of compressible multiphase flow using a Discontinuous Galerkin based multiscale approach Inproceedings
Proceedings of the 12th Triennial International Conference on Liquid Atomization and Spray Systems, Heidelberg, Germany., 2012.
Discontinuous Galerkin schemes for the direct numerical simulation of fluid flow and acoustics Inproceedings
42nd AIAA Fluid Dynamics Conference and Exhibit. New Orleans: American Institute of Aeronautics and Astronautics, pp. 2012–2187, 2012.
A discontinuous Galerkin based multiscale method for compressible multiphase flow Inproceedings
Proceedings of the Seventh International Conference on Computational Fluid Dynamics (ICCFD7), 2012.