/ALE/MUSCL

Block Format Keyword This option allows for a second order MUSCL (Monotonic Upstream-Centered Scheme for Conservation Laws) reconstruction of volumic fraction fields when using Multi-Material laws (LAW51), and for a full second order scheme (time and space) when using material LAW151.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/ALE/MUSCL
BETA IFLAG              

Definition

Field Contents SI Unit Example
BETA Compression coefficient for gradient reconstruction. Must be between 0.0. and 2.0.
= 1e-20
Classical upwind scheme (no gradient reconstruction).
= 1.0
Exact second order gradient reconstruction.
= 2.0 (Default)
Over-compressive gradient limiter.

(Real)

 
IFLAG Formulation flag for LAW151 second order.
= 0 (Default)
Full second order in time and space for all variables.
= 1
Only volume fraction field is reconstructed with MUSCL method (as for LAW51).

(Integer)

 

Comments

  1. Finite volume schemes classically rely on the computation of a numerical flux along mesh faces (in 3D) or mesh edges (in 2D). A convenient, yet very diffusive, way to get a robust and stable scheme is to use the upwind technique. The MUSCL1 technique combines an upwind approach to a second order reconstruction of the volume fraction field, allowing for a better localization of the interface between fluids, and much less numerical diffusion.
  2. /ALE/MUSCL is only compatible with LAW51 for 2D and 3D modeling. It is currently enabled only for volume fraction. A slight computational overcost is to be expected.
  3. /ALE/MUSCL is also compatible with multimaterial LAW151 and provides a full second order solution (time and space) when IFLAG=0 (default). It is possible to use MUSCL only for the volume fraction field by setting IFLAG=1. The behavior is then the same as for LAW51.
  4. As of Version 2022.0, MUSCL scheme is enabled by default. It can be disabled by using Engine option /ALE/MUSCL/OFF.
1 B. Van Leer, Towards the Ultimate Conservative Difference Scheme, V. A Second Order Sequel to Godunov’s Method, J. Comp. Phys., 87, 408—463, 1979