Queen Mary University of London
EMS602: Computer Aided Engineering,
CFD
Flow over a compressor stator – influence of the mesh and the
numerical method.
Abstract
This report dwells into the world of Computational Fluid Dynamics, revolving around on the aerofoil
profile of a compressor stator blade. Using StarCCM+ as the simulation software, the report uses basic
knowledge from governing PDE’s to analyse different mesh sizes for accuracy on results like ‘Velocity
Magnitude’, ‘Force Coefficients’ like ‘Drag’ and ‘Downforce’ and ‘Static Pressure’ values. The coloured
1
, contour lines help investigate the flow characteristics around the profile which helps in the understanding
of boundary layers, stagnation points at the trailing and leading edge along with flow separation. The
results at the end are analysed based on number of mesh elements and their size which is used to decide
the mesh size for a simulation to generate closer to reality results. A percentage error plot between the
manually calculated theoretical values and simulation values with different mesh sizes and order of
simulation is used to further strengthen the conclusion of the report.
Results indicate that a finer mesh and a 2nd order simulation significantly enhance accuracy even under
ideal fluid conditions like having inviscid flow and incompressible fluid. The study calls for a
consideration of fluid conditions, mesh convergence, proposing future works on custom grid sizes with
mesh-control for optimal computational efficiency in critical regions like around the profile of the
aerofoil instead of the inlet and outlet.
Table of Contents
1 Introduction ........................................................................................................................................................... 2
1.1 Flow Parameters and Solver Settings ............................................................................................................ 3
1.2 Flow Physics ................................................................................................................................................. 3
1.2.1 Stagnation Point ..................................................................................................................................... 3
1.2.2 Boundary Layer...................................................................................................................................... 3
1.2.3 Lift and Drag .......................................................................................................................................... 3
1.2.4 Mesh Type .............................................................................................................................................. 4
1.3 Boundary Conditions..................................................................................................................................... 4
1.4 Mesh and Residual Convergence ................................................................................................................... 4
2 Results ................................................................................................................................................................... 4
2.1 Effect of mesh refinement and 2nd order accuracy....................................................................................... 4
2.2 Comparison of ‘other’ vs. ‘sequence’ simulations ........................................................................................ 5
2.3 Quantitative comparison of total pressure, force coefficients ....................................................................... 6
3 Summary ................................................................................................................................................................ 7
4 References .............................................................................................................................................................. 7
5 Appendix ................................................................................................................................................................ 8
1 Introduction
2
EMS602: Computer Aided Engineering,
CFD
Flow over a compressor stator – influence of the mesh and the
numerical method.
Abstract
This report dwells into the world of Computational Fluid Dynamics, revolving around on the aerofoil
profile of a compressor stator blade. Using StarCCM+ as the simulation software, the report uses basic
knowledge from governing PDE’s to analyse different mesh sizes for accuracy on results like ‘Velocity
Magnitude’, ‘Force Coefficients’ like ‘Drag’ and ‘Downforce’ and ‘Static Pressure’ values. The coloured
1
, contour lines help investigate the flow characteristics around the profile which helps in the understanding
of boundary layers, stagnation points at the trailing and leading edge along with flow separation. The
results at the end are analysed based on number of mesh elements and their size which is used to decide
the mesh size for a simulation to generate closer to reality results. A percentage error plot between the
manually calculated theoretical values and simulation values with different mesh sizes and order of
simulation is used to further strengthen the conclusion of the report.
Results indicate that a finer mesh and a 2nd order simulation significantly enhance accuracy even under
ideal fluid conditions like having inviscid flow and incompressible fluid. The study calls for a
consideration of fluid conditions, mesh convergence, proposing future works on custom grid sizes with
mesh-control for optimal computational efficiency in critical regions like around the profile of the
aerofoil instead of the inlet and outlet.
Table of Contents
1 Introduction ........................................................................................................................................................... 2
1.1 Flow Parameters and Solver Settings ............................................................................................................ 3
1.2 Flow Physics ................................................................................................................................................. 3
1.2.1 Stagnation Point ..................................................................................................................................... 3
1.2.2 Boundary Layer...................................................................................................................................... 3
1.2.3 Lift and Drag .......................................................................................................................................... 3
1.2.4 Mesh Type .............................................................................................................................................. 4
1.3 Boundary Conditions..................................................................................................................................... 4
1.4 Mesh and Residual Convergence ................................................................................................................... 4
2 Results ................................................................................................................................................................... 4
2.1 Effect of mesh refinement and 2nd order accuracy....................................................................................... 4
2.2 Comparison of ‘other’ vs. ‘sequence’ simulations ........................................................................................ 5
2.3 Quantitative comparison of total pressure, force coefficients ....................................................................... 6
3 Summary ................................................................................................................................................................ 7
4 References .............................................................................................................................................................. 7
5 Appendix ................................................................................................................................................................ 8
1 Introduction
2
