aerosandbox.aerodynamics.aero_3D.aero_buildup_submodels.fuselage_aerodynamics_utilities#
Module Contents#
Functions#
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Returns the transonic critical Mach number for a streamlined fuselage. |
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A fit for the eta parameter (crossflow lift multiplier) of a fuselage, as described in: |
A fit for the fuselage base drag coefficient of a cylindrical fuselage, as described in: |
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Computes the form factor of a fuselage as a function of various geometrical parameters. |
- aerosandbox.aerodynamics.aero_3D.aero_buildup_submodels.fuselage_aerodynamics_utilities.critical_mach(fineness_ratio_nose)[source]#
Returns the transonic critical Mach number for a streamlined fuselage.
Fitted to data from Raymer “Aircraft Design: A Conceptual Approach” 2nd Ed., Fig. 12.28. See figure + study + fit in: /studies/FuselageCriticalMach/
- Parameters:
fineness_ratio_nose (float) –
The fineness ratio of the nose section of the fuselage.
Specifically, fineness_ratio_nose = 2 * L_n / d, where:
L_n is the length from the nose to the longitudinal location at which the fuselage cross section
becomes essentially constant, and:
d is the body diameter at that location.
- Return type:
float
Returns: The critical Mach number
- aerosandbox.aerodynamics.aero_3D.aero_buildup_submodels.fuselage_aerodynamics_utilities.jorgensen_eta(fineness_ratio)[source]#
A fit for the eta parameter (crossflow lift multiplier) of a fuselage, as described in:
Jorgensen, Leland Howard. “Prediction of Static Aerodynamic Characteristics for Slender Bodies Alone and with Lifting Surfaces to Very High Angles of Attack”. NASA TR R-474. 1977.
Fits performed in /studies/FuselageJorgensenEtaFitting/
- Parameters:
fineness_ratio (float) – The fineness ratio of the fuselage. (length / diameter)
- Return type:
float
Returns: An estimate of eta.
- aerosandbox.aerodynamics.aero_3D.aero_buildup_submodels.fuselage_aerodynamics_utilities.fuselage_base_drag_coefficient(mach)[source]#
A fit for the fuselage base drag coefficient of a cylindrical fuselage, as described in:
- MIL-HDBK-762: DESIGN OF AERODYNAMICALLY STABILIZED FREE ROCKETS:
Section 5-5.3.1 Body-of-Revolution Base Drag, Rocket Jet Plume-Off
Figure 5-140: Effects of Mach Number and Reynolds Number on Base Pressure
Fits in /studies/FuselageBaseDragCoefficient
- Parameters:
mach (float) – Mach number [-]
- Return type:
float
Returns: Fuselage base drag coefficient
- aerosandbox.aerodynamics.aero_3D.aero_buildup_submodels.fuselage_aerodynamics_utilities.fuselage_form_factor(fineness_ratio, ratio_of_corner_radius_to_body_width=0.5)[source]#
Computes the form factor of a fuselage as a function of various geometrical parameters.
Assumes the body cross section is a rounded square with constant-radius-of-curvature fillets. Body cross section can therefore vary from a true square to a true circle.
Uses the methodology described in:
Götten, Falk; Havermann, Marc; Braun, Carsten; Marino, Matthew; Bil, Cees. “Improved Form Factor for Drag Estimation of Fuselages with Various Cross Sections. AIAA Journal of Aircraft, 2021. DOI: 10.2514/1.C036032
https://arc.aiaa.org/doi/10.2514/1.C036032
Assumes fully turbulent flow. Coefficient of determination found in the paper above was 0.95.
Note: the value returned does not account for any base separation (other than minor aft-closure separation). The equations were also fit to relatively-shape-optimized fuselages, and will be overly-optimistic for unoptimized shapes.
- Parameters:
fineness_ratio (float) – The fineness ratio of the body (length / diameter).
ratio_of_corner_radius_to_body_width (float) – A parameter that describes the cross-sectional shape of the fuselage.
Precisely –
A value of 0 corresponds to a true square.
A value of 0.5 (default) corresponds to a true circle.
width. (this is ratio of corner radius to body) –
A value of 0 corresponds to a true square.
A value of 0.5 (default) corresponds to a true circle.
Returns: The form factor of the body, defined as:
C_D = C_f * form_factor * (S_wet / S_ref)