Shape analysis
Where it is
Section titled “Where it is”Not a setup-tree node. Embedded in the application.
Controls
Section titled “Controls”ANALYSIS
Section titled “ANALYSIS”Objective
Section titled “Objective”- Control: choice (
ComboRow) - Options:
Drag,Lift,Moment,Efficiency
The in-app guidance depends on the case:
- Minimise the drag coefficient of the design surfaces.
- Maximise the lift coefficient.
- Minimise the pitching moment coefficient about Z.
- Maximise lift over drag.
Compressible
Section titled “Compressible”- Control: on/off (
ToggleRow)
Compressible states the flow by Mach number and, for a viscous case, Reynolds number; SU2 supplies standard air. Incompressible states it by velocity with a density and viscosity of your own.
Viscous
Section titled “Viscous”- Control: on/off (
ToggleRow)
Off is Euler: no boundary layer, no friction drag, fast. On is RANS with the Spalart-Allmaras model, and the mesh needs boundary layers on the body to mean anything.
- Control: value (
ValueField) - Value modes: none (plain entry)
- Shown when:
ShapeState.compressible
Free-stream Mach number. Above about 0.7 the flow round a blunt body is transonic and the run is slower to settle.
Velocity
Section titled “Velocity”- Control: value (
ValueField) - Unit: m/s
- Value modes: none (plain entry)
- Shown when:
!ShapeState.compressible
Angle of attack
Section titled “Angle of attack”- Control: value (
ValueField) - Unit: deg
- Value modes: none (plain entry)
The free stream comes along +X, turned by this angle towards +Y.
Reynolds
Section titled “Reynolds”- Control: value (
ValueField) - Value modes: none (plain entry)
- Shown when:
ShapeState.compressible && ShapeState.viscous
Based on the reference length below.
Density
Section titled “Density”- Control: value (
ValueField) - Unit: kg/m³
- Value modes: none (plain entry)
- Shown when:
!ShapeState.compressible
Viscosity
Section titled “Viscosity”- Control: value (
ValueField) - Unit: Pa·s
- Value modes: none (plain entry)
- Shown when:
!ShapeState.compressible && ShapeState.viscous
Reference length
Section titled “Reference length”- Control: value (
ValueField) - Unit: m
- Value modes: none (plain entry)
The chord the moment and Reynolds number are based on.
Reference area
Section titled “Reference area”- Control: value (
ValueField) - Unit: m²
- Value modes: none (plain entry)
The force coefficients are per this area. Zero lets SU2 use the wetted area of the design surfaces.
SOLVER
Section titled “SOLVER”Iterations
Section titled “Iterations”- Control: value (
ValueField) - Value modes: none (plain entry)
Per flow solve and per adjoint solve. SU2 stops earlier when the residual drops eight orders.
- Control: value (
ValueField) - Value modes: none (plain entry)
The implicit solver’s step size. Lower if the residual diverges.
SEARCH
Section titled “SEARCH”Cycles
Section titled “Cycles”- Control: value (
ValueField) - Value modes: none (plain entry)
- Shown when:
root.optimising
Design cycles: flow, adjoint, gradient, deform. Each is two full solves, so the run is roughly this many times a sensitivity map.
Step size
Section titled “Step size”- Control: value (
ValueField) - Unit: m
- Value modes: none (plain entry)
- Shown when:
root.optimising
How far the most-sensitive control point moves per cycle; the others move in proportion. A few percent of the body’s span is a sane start - too far and the mesh folds.
Move along
Section titled “Move along”- Control: choice (
ComboRow) - Options:
X,Y,Z - Shown when:
root.optimising
The axis the control points move along. Y for an aerofoil’s camber and thickness with the stream along X.
FFD degree I
Section titled “FFD degree I”- Control: value (
ValueField) - Value modes: none (plain entry)
- Shown when:
root.optimising
FFD degree J
Section titled “FFD degree J”- Control: value (
ValueField) - Value modes: none (plain entry)
- Shown when:
root.optimising
FFD degree K
Section titled “FFD degree K”- Control: value (
ValueField) - Value modes: none (plain entry)
- Shown when:
root.optimising
The Bezier box round the body has (I+1)(J+1)(K+1) control points - … here. Each is one design variable; more give the shape more freedom and the gradient more noise.
FAR FIELD
Section titled “FAR FIELD”Air padding
Section titled “Air padding”- Control: value (
ValueField) - Unit: spans
- Value modes: none (plain entry)
How far the meshed air reaches beyond the body, in multiples of its largest dimension. Takes effect at the next mesh. Five spans is a SMALL far field - SU2’s own aerofoil cases go to a hundred chords - so expect the coefficients to shift a little with this number until it is large.
Problems reported against this step
Section titled “Problems reported against this step”The application reports no problems against this step.
… marks a value the application computes at run time, so the source carries no fixed text for it.