PhD, 156ppThis thesis investigates stabilisation of the SIMPLE-family discretisations for incompressible
flow and their discrete adjoint counterparts. The SIMPLE method is
presented from typical \prediction-correction" point of view, but also using a pressure
Schur complement approach, which leads to a wider class of schemes. A novel semicoupled
implicit solver with velocity coupling is proposed to improve stability. Skewness
correction methods are applied to enhance solver accuracy on non-orthogonal
grids. An algebraic multi grid linear solver from the HYPRE library is linked to
flow and discrete adjoint solvers to further stabilise the computation and improve
the convergence rate. With the improved implementation, both of
flow and discrete adjoint solvers can be applied to a wide range of 2D and 3D test cases. Results
show that the semi-coupled implicit solver is more robust compared to the standard
SIMPLE solver. A shape optimisation of a S-bend air flow duct from a VW Golf
vehicle is studied using a CAD-based parametrisation for two Reynolds numbers.
The optimised shapes and their flows are analysed to con rm the physical nature of
the improvement.
A first application of the new stabilised discrete adjoint method to a reverse osmosis
(RO) membrane channel flow is presented. A CFD model of the RO membrane
process with a membrane boundary condition is added. Two objective functions,
pressure drop and permeate flux, are evaluated for various spacer geometries such as
open channel, cavity, submerged and zigzag spacer arrangements. The flow and the
surface sensitivity of these two objective functions is computed and analysed for these
geometries. An optimisation with a node-base parametrisation approach is carried
out for the zigzag con guration channel flow in order to reduce the pressure drop.
Results indicate that the pressure loss can be reduced by 24% with a slight reduction
in permeate flux by 0.43%.Queen Mary-China Scholarship Council Co-funded Scholarship No. 201206280018
