Abstract:
An investigation into the current methods employed to conserve vorticity in
numerical calculations is undertaken. Osher’s flux for the artificial compressibility
equations is derived, implemented and validated in Cranfield University’s second
order finite volume compressible flow solver MERLIN. Characteristic
Decomposition is applied as a method of vorticity conservation in both the
compressible and artificial compressibility MERLIN solvers. The performance of this
method for vorticity conservation in both these solvers is assessed. Following a
discussion of the issues associated with application of limiter functions on
unstructured grids three modified versions of the method of Characteristic
Decomposition are proposed and tested in both the compressible and incompressible
solvers. It is concluded that the method of Characteristic Decomposition is an
effective method for improving vorticity conservation and compares favourably in
terms of increased computational cost to vorticity conservation through grid
refinement.
