DI-SESS-82330

Computational Aerodynamic Model (CAM)

Describes a digital Computational Aerodynamic Model (CAM) of an air vehicle system used for independent computational modeling of external aerodynamics, delivered per digital engineering processes.

Approval DateNovember 5, 2020

AMSC NumberF10202

Preparing Activity11 (AFLCMC/EZFT)

Project NumberSESS-2020-049

OPR—

DTIC ApplicableNo

GIDEP ApplicableNo

Limitation—

Applicable Forms—

Approval Limitation—

Form Version—

DID Formatfree_text

963C CompliantYes

DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.

Supersedes

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Description & Purpose

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Application & Interrelationship

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Use & Relationship

Digital engineering processes routinely result in the development of computational models. These models can be in a variety of formats depending on the computational processes used. This Data Item Description (DID) describes a digital model that will be used for computational aerodynamic analysis.

This DID contains the format, content, and intended use information for the data deliverable resulting from the work task described in the solicitation.

Preparation Instructions

1Reference documentsNone.

2FormatThe Computational Aerodynamic Model (CAM) shall be in either native computer-aided design (CAD), Standard for the Exchange of Product (STEP), or Parasolid format.

3ContentThe Computational Aerodynamic Model shall include a digital model of the air vehicle system to be used for independent computational modeling of the external aerodynamics. The Computational Aerodynamic Model shall include the following:

3.1Outer mold line (OML) of the entire air vehicle

3.2The wing shall be in jig positionThe wing shall be in jig position accompanied by a wing structural finite element or modal model to define the surface deflection across the flight envelope as a function of aircraft weight and the exterior aerodynamic forces. If a finite element model (FEM) or modal model is not available, the surface deflection definition across the flight envelope as a function of aircraft weight and flight condition (Mach number and altitude) shall be included.

3.3All aerodynamic control surfaces with hinge line locationsAll aerodynamic control surfaces with hinge line locations, minimum and maximum deflections, and optimized control schedules across the flight envelope as a function of aircraft weight and flight conditions (Mach number and altitude).

3.4All deployable surfaces, such as flaps, slats, and spoilersAll deployable surfaces, such as flaps, slats, and spoilers, and control schedules across the flight envelope.

3.5Propulsion system installation definitionwhich shall include the inlet, from the inlet lip to the first fan or compressor stage or aerodynamic interface plane, the nozzle or exhaust system from the last turbine stage to the nozzle exit, and the bypass duct from fan exit to bypass exit. If a mixed-core or bypass system is used, the model shall include the nozzle from the mixing plane to the nozzle exit. All auxiliary airflow inlets and exits, including internal geometry and mass flow rates across the flight envelope, shall be included. If a propeller is used, the propeller surface geometry and the range of propeller blade pitch and control schedule shall be included.

3.6A propulsion system digital performance model (or cycle deck)A propulsion system digital performance model (or cycle deck), including propellers, across the flight envelope as a function of engine speed and flight condition. The digital engine performance model output shall include the net thrust, gross thrust (installed and uninstalled), and installation effects; the mass flow rate at the inlet, aerodynamic interface plane, nozzle entrance (after last turbine stage), nozzle exit, bypass duct entrance and exit, and mixed stream plane (if applicable); total temperature, total pressure, and Mach after last turbine stage, nozzle exit, bypass duct entrance and exit, mixed-stream nozzle entrance; and the original equipment manufacturer (OEM) definition of force and moment accounting between propulsion system and external aerodynamics.

3.7All doors or bays to be opened in flightAll doors or bays to be opened in flight, hinge line locations, and internal geometry definition.

3.8Suspension equipment of all external storesSuspension equipment of all external stores, external store configuration, and OML definition.

3.9Geometric definition of the landing gear, both compressed and extendedThe dynamics of linkages during retraction and extension shall be included.

3.10All alternate mission equipmentAll alternate mission equipment, such as antennas, pods, etc.

3.11Chaff and flare dispensers

3.12Reference quantities and coordinate systemwhich shall be comprised of:

3.12.1The origin of the model coordinate systemwhich shall be located at the origin of the modeled air vehicle (i.e., the model origin shall be located at Fuselage Station 0, Buttock Line 0, Water Line 0, as that location is defined for the actual aircraft).

3.12.2Coordinate system for each geometric componentCoordinate system for each geometric component, as well as any corresponding Fuselage Station, Water Line, Buttock Line, Wing Station, etc.

3.12.3Reference length(s), area(s), and moment reference point location(s)Reference length(s), area(s), and moment reference point location(s) for aerodynamic performance coefficients.

3.12.4Engineering units for all quantities

References

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