# Convection¶

Some numerical methods, most notaby the algebraic Volume of Fluid method for interface capturing in free surface flows, require the selection of a convective flux.

## Upwind¶

The simplest flux for the colour function is pure upwind. This flux leads to a very diffusive free surface when used with a piecewise constant VOF colour function.

convection:
c:
convection_scheme: Upwind


## HRIC¶

High Resolution Interface Capturing. A compressive flux designed to be used in combination with a piecewise constant VOF colour function.

Three versions are implemented

• Standard HRIC (HRIC, default, the only one that is well tested) [MPSS98]

• Modified HRIC (MHRIC, practically untested code, use with caution) [ANS13]

• Refined HRIC (RHRIC, practically untested code, use with caution) [PKKV10]

convection:
c:
convection_scheme: HRIC
HRIC_version: HRIC          # <-- not needed, HRIC is default


## CICSAM¶

Compressive Interface Capturing Scheme for Arbitrary Meshes. A compressive flux designed to be used in combination with a piecewise constant VOF colour function.

“Numerical prediction of two fluid systems with sharp interfaces”, Imperial College, London, 1997, Onno Ubbink

convection:
c:
convection_scheme: CICSAM