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Introduction to APM
Quick start
Release notes
User guide
The configuration file
Calculating surface pressure
Calculating skin friction
Creating control surfaces
Creating actuator disks
The mesh file
Preprocessor
Solver
Output files
Examples
Sphere
Ellipsoid
NACA4412 wing
NACA0015 wing
CaradonnaTung rotor in hover
NREL Phase IV wind turbine
AGARDAR303 E6
Wingtail configuration
Fixedwing UAV
Aerosonde UAV
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The configuration file
The
.conf
file contains different options which specify the problem that APM will solve. The contents of an example
.conf
file are shown below:
c_ref = 1
b_ref = 1
S_ref = 1
x_cg = 0
y_cg = 0
z_cg = 0
trailing_edge_angle = 140
p_ref = 101325
rho_ref = 1.225
mu_ref = 1.789e5
norm_V_ref = 1
M_ref = 0
alpha = 0
beta = 0
p = 0
q = 0
r = 0
dt = 1
N_timesteps = 1
wake_alignment = 0
wake_angle = 0
json_output = 0
paraview_output = 0
tecplot_output = 0
restart_from_checkpoint = 0
doublet_gradient_scheme = 0
neighbour_tolerance = 1e6
tip_panels =
The values in the above .conf file are in SI units  m, kg, s. You can use different units as long as they are consistent across the .conf file.
Refer to the table below for a detailed description of each option.
Option
Dimension
Description
Default value
c_ref
â€‹
$L$
â€‹
Reference chord, used for nondimensionalisation of the aerodynamic coefficients
1
b_ref
â€‹
$L$
â€‹
Reference span, used for nondimensionalisation of the aerodynamic coefficients
1
S_ref
â€‹
$L^2$
â€‹
Reference area, used for nondimensionalisation of the aerodynamic coefficients
1
x_cg, y_cg, z_cg
â€‹
$L$
â€‹
Location of the centre of gravity
0
trailing_edge_angle

Edges sharper than the trailing edge angle in degrees are identified as trailing edges
140
p_ref
â€‹
$M/(L{\cdot}T^2)$
â€‹
Reference pressure
101325
rho_ref
â€‹
$M/L^3$
â€‹
Reference density
1.225
mu_ref
â€‹
$M/(L{\cdot}T)$
â€‹
Reference dynamic viscosity
1.789e5
norm_V_ref
â€‹
$L/T$
â€‹
Reference freestream speed
1
M_ref

Reference Mach number (used for compressibility corrections)
0
alpha, beta

Angle of attack and angle of sideslip with respect to the freestream in degrees
0
p, q, r
â€‹
$1/T$
â€‹
Roll, pitch, and yaw rates in degrees/sec
0
dt
â€‹
$T$
â€‹
Time step
1
N_timesteps

Number of timesteps
1
wake_alignment, wake_angle

Specifies how the wake aligns with respect to the trailing edges
0
json_output, paraview_output, tecplot_output

Enables or disables JSON, ParaView, and Tecplot output
0
restart_from_checkpoint

Instructs the solver to restart the solution from a checkpoint
0
doublet_gradient_scheme

Instructs the solver how to calculate the
doublet gradient
â€‹
0
neighbour_tolerance

Specifies the neighbour tolerance criteria
1e6
tip_panels

Instructs the solver to label specific panels as type 6
Empty
â€‹
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Calculating surface pressure
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1yr ago
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