aerosandbox.library.aerodynamics.components
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Module Contents#
Functions#
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Computes the drag area (CDA) of a typical control usage as used on a well-manufactured RC airplane. |
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Computes the drag area (CDA) of the gaps associated with a typical wing control surface. |
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Computes the drag area (CDA) of a protruding bolt or rivet. |
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Computes the drag area (CDA) of a sheet metal joint that is perpendicular to the flow. |
- aerosandbox.library.aerodynamics.components.CDA_control_linkage(Re_l, linkage_length, is_covered=False, is_top=False)[source]#
Computes the drag area (CDA) of a typical control usage as used on a well-manufactured RC airplane.
The drag area (CDA) is defined as: CDA == D / q, where:
D is the drag force (dimensionalized, e.g., in Newtons)
q is the freestream dynamic pressure (dimensionalized, e.g., in Pascals)
See study with original data at AeroSandbox/studies/LinkageDrag.
Data from:
Hepperle, Martin. “Drag of Linkages”. https://www.mh-aerotools.de/airfoils/linkage.htm
Summarizes data from “Werner Würz, published in the papers of the ISF-Seminar in December 1989 in Baden, Switzerland.”
- Parameters:
Re_l (Union[float, aerosandbox.numpy.ndarray]) – Reynolds number, with reference length as the length of the linkage.
linkage_length (Union[float, aerosandbox.numpy.ndarray]) – The length of the linkage. [m]
is_covered (Union[bool, aerosandbox.numpy.ndarray]) – A boolean of whether an aerodynamic fairing is placed around the linkage.
is_top (Union[bool, aerosandbox.numpy.ndarray]) – A boolean of whether the linkage is on the top surface of the wing (True) or the bottom surface ( False). Differences in local boundary layer and inviscid effects cause local velocity changes.
- Return type:
Union[float, aerosandbox.numpy.ndarray]
Returns: The drag area [m^2] of the control linkage.
- aerosandbox.library.aerodynamics.components.CDA_control_surface_gaps(local_chord, control_surface_span, local_thickness_over_chord=0.12, control_surface_hinge_x=0.75, n_side_gaps=2, side_gap_width=None, hinge_gap_width=None)[source]#
Computes the drag area (CDA) of the gaps associated with a typical wing control surface. (E.g., aileron, flap, elevator, rudder).
The drag area (CDA) is defined as: CDA == D / q, where:
D is the drag force (dimensionalized, e.g., in Newtons)
q is the freestream dynamic pressure (dimensionalized, e.g., in Pascals)
This drag area consists of two sources:
Chordwise gaps at the side edges of the control surface (“side gaps”)
Spanwise gaps at the hinge line of the control surface (“hinge gap”)
- Parameters:
local_chord (float) – The local chord of the wing at the midpoint of the control surface. [meters]
control_surface_span (float) – The span of the control surface. [meters]
local_thickness_over_chord (float) – The local thickness-to-chord ratio of the wing at the midpoint of the control surface. [nondimensional] For example, this is 0.12 for a NACA0012 airfoil.
control_surface_hinge_x (float) – The x-location of the hinge line of the control surface, as a fraction of the local chord. [nondimensional] Defaults to x_hinge / c = 0.75, which is typical for an aileron.
n_side_gaps (int) –
The number of “side gaps” to count on this control surface when computing drag. Defaults to 2 ( i.e., one inboard gap, one outboard gap), which is the simplest case of a wing with a single partial-span aileron. However, there may be cases where it is best to reduce this to 1 or 0. For example:
A wing with a single full-span aileron would have 1 side gap (at the wing root, but not at the tip).
- A wing with a flap and aileron that share a chordwise gap would be best modeled by setting
n_side_gaps = 1 ( so that no double-counting occurs).
side_gap_width (float) – The width of the chordwise gaps at the side edges of the control surface [meters]. If this is left as the default (None), then a typical value will be computed based on the local chord and control surface span.
hinge_gap_width (float) – The width of the spanwise gap at the hinge line of the control surface [meters]. If this is left as the default (None), then a typical value will be computed based on the local chord.
- Return type:
float
- Returns: The drag area [m^2] of the gaps associated with the control surface. This should be added to the “clean”
wing drag to get a more realistic drag estimate.
- aerosandbox.library.aerodynamics.components.CDA_protruding_bolt_or_rivet(diameter, kind='flush_rivet')[source]#
Computes the drag area (CDA) of a protruding bolt or rivet.
- The drag area (CDA) is defined as: CDA == D / q, where:
D is the drag force (dimensionalized, e.g., in Newtons)
q is the freestream dynamic pressure (dimensionalized, e.g., in Pascals)
- Parameters:
diameter (float) – The diameter of the bolt or rivet. [meters]
kind (str) –
The type of bolt or rivet. Valid options are:
”flush_rivet”
”round_rivet”
”flat_head_bolt”
”round_head_bolt”
”cylindrical_bolt”
”hex_bolt”
Returns: The drag area [m^2] of the bolt or rivet.
- aerosandbox.library.aerodynamics.components.CDA_perpendicular_sheet_metal_joint(joint_width, sheet_metal_thickness, kind='butt_joint_with_inside_joiner')[source]#
- Computes the drag area (CDA) of a sheet metal joint that is perpendicular to the flow.
(E.g., spanwise on the wing, or circumferential on the fuselage).
The drag area (CDA) is defined as: CDA == D / q, where:
D is the drag force (dimensionalized, e.g., in Newtons)
q is the freestream dynamic pressure (dimensionalized, e.g., in Pascals)
- Parameters:
joint_width (float) – The width of the joint (perpendicular to the airflow, e.g., spanwise on a wing). [meters]
sheet_metal_thickness (float) – The thickness of the sheet metal. [meters]
kind (str) –
The type of joint. Valid options are:
”butt_joint_with_inside_joiner”
”butt_joint_with_inside_weld”
”butt_joint_with_outside_joiner”
”butt_joint_with_outside_weld”
”lap_joint_forward_facing_step”
”lap_joint_backward_facing_step”
”lap_joint_forward_facing_step_with_bevel”
”lap_joint_backward_facing_step_with_bevel”
”lap_joint_forward_facing_step_with_rounded_bevel”
”lap_joint_backward_facing_step_with_rounded_bevel”
”flush_lap_joint_forward_facing_step”
”flush_lap_joint_backward_facing_step”
Returns: The drag area [m^2] of the sheet metal joint.