1 VSP Workshop 2017 OpenVSP Parasite Drag Build Upopenvsp.org/wiki/lib/exe/fetch.php?media=workshop17:... · 2018-04-01 · NNX09CC86P SBIR Review, Presented to NASA, July 7VSP Workshop

NNX09CC86P SBIR Review, Presented to NASA, July 7th, 2009VSP Workshop 2017 Aug. 30th – Sep. 1st

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Empirical Systems Aerospace, Inc., Oceano, CA www.esaero.com

VSP Workshop 2017

OpenVSP – Parasite Drag Build Up

Presented by:

Bryan Schmidt

Empirical Systems Aerospace, Inc.

Work Support By:

AFRL SBIR Phase II


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Introduction

Goal

• Reduce the time it takes to complete a

parasitic build up for conceptual aircraft

utilizing OpenVSPs’ internal geometry

calculations


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Approach

• Uses existing geometry, equations for friction coefficient, form factor

equations, and flow conditions to create a full parasitic drag build up

of the selected components

– Plethora of options for calculated friction coefficient and calculated form factor

– Manually set freestream flow parameters or use a standard atmosphere model

• Export data to organized, parsable CSV file


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Friction Coefficient Equations Used

• Laminar:– Blasius

• Turbulent:– “Fluid-Dynamic Drag” by S. F. Hoerner

• Prandtl-Karman

• Approximate Schoenherr

• Intrinsic Schoenherr

• Schultz-Grunow 1

– “A Simple New Analysis of Compressible Turbulent Two-Dimensional Skin Friction Under

Arbitrary Conditions” by F. M. White and G. H. Christoph• Schultz-Grunow 2

• Blasius Power Law

• Intrinsic Von-Karman

• Prandtl-Schlichting

• White-Christoph Best Fit

• White-Christoph w/ Heat Transfer

– “Viscous Fluid Flow” by Frank M. White• White Power Law

• Prandtl Power Law

• ‘Exact’ Solution

• White w/ Roughness

• Schlichting w/ Roughness

– “Thrust and Drag: Its Prediction and Verification” by Eugene E. Covert• Intrinsic Karman-Schoenherr


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Form Factor Equations Used

• Wing:

– “Zero Lift Drag and Drag Divergence Prediction for Finite Wings in Aircraft

Design” – AIAA Paper• EDET Conventional

• EDET Advanced

• DATCOM

• Hoerner

• Williams

• Kroo

• Torenbeek

– “Thrust and Drag: Its Prediction and Verification” by Eugene E. Covert• Covert

• Body:

– “Thrust and Drag: Its Prediction and Verification” by Eugene E. Covert• Covert Body

• Covert Nacelle

– “Fluid Dynamic Drag” by S.F. Hoerner• Hoerner Streamlined

– “Synthesis of Subsonic Airplane Design” by E. Torenbeek• Torenbeek

• Shevell


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Order of Operations

1

Add and Edit Geoms

Edit Options as Desired

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Order of Operations – Cont.

2a 2bAdd Excrescence Edit Excrescence


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3

Options as Desired

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Calculate CD0 or Export to CSV


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• Use scrollbar or expand

window to see rest of

data

• Press “Export to CSV” to

output the data into an

organized CSV file

• Changes to Freestream

properties can be

changed from here to

witness changes to CD0

• If Geoms are added,

everything is cleared and

must calculate again

Final Results5


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Grouping

• Used to group the

wetted area of

geometries that

are better suited

as “one” geometry

• Can only be

attached to

parent(s) of similar

geometry type


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Subsurface Handling

• 3 choices for subsurface handling

– Same as parent

– Separate treatment

– Zero drag

• Separate treatment comes with the ability to control all

parameters similar to new geometry


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PARASITE DRAG BUILD UP DATA

Mach Altitude (ft) Vinf (ft/s) S_ref (ft^2)

0.649737 40000 629 598.00128

Temp (°F) Pressure (lbf/ft^2) Density (slug/ft^3)

-69.7 391.683791 0.000585

Lam Cf Eqn Turb Cf Eqn

Blasius Implicit Karman-Schoenerr

Component Name S_wet (ft^2) L_ref (ft) t/c or d/l FF FF Eqn Type Re (1e6) % Lam Cf (1e-3) Q (Interference Factor) f Cd % Total

Wing 1089.00712 9.808761 0.162611 1.367174 Hoerner 8169468.569 0 0.003036 1 4.520013 0.007559 0.446553

Wing_0 544.50356 9.808761 0.162611 1.367174 Hoerner 8169468.569 0 0.003036 1 2.260007 0.003779 0.223276

Wing_1 544.50356 9.808761 0.162611 1.367174 Hoerner 8169468.569 0 0.003036 1 2.260007 0.003779 0.223276

Fuse 989.029556 49.557828 0.163706 1.130066 Hoerner Streamlined Body 41275458.14 0 0.002356 1 2.633716 0.004404 0.260197

Fuse_0 989.029556 49.557828 0.163706 1.130066 Hoerner Streamlined Body 41275458.14 0 0.002356 1 2.633716 0.004404 0.260197

H-Tail 355.466618 7.001429 0.099919 1.205818 Hoerner 5831313.037 0 0.003212 1 1.376626 0.002302 0.136003

H-Tail_0 177.733309 7.001429 0.099919 1.205818 Hoerner 5831313.037 0 0.003212 1 0.688313 0.001151 0.068002

H-Tail_1 177.733309 7.001429 0.099919 1.205818 Hoerner 5831313.037 0 0.003212 1 0.688313 0.001151 0.068002

V-Tail 246.350315 9.669314 0.099919 1.205818 Hoerner 8053326.672 0 0.003043 1 0.903955 0.001512 0.089306

V-Tail_0 246.350315 9.669314 0.099919 1.205818 Hoerner 8053326.672 0 0.003043 1 0.903955 0.001512 0.089306

Excrescences

Miscellaneous Count (10000*CD) 8.5 0.00085 0

Cowl Boattail CD 0.0003 0.0003 0

Geometry Sub-Total: 9.43431 0.015776 0.932059

Excrescence Sub-Total: 0.687701 0.00115 0.067941

Totals: 10.122012 0.016926 1

Validation and Verification.

• Using Technical Report Data for

Dimensions, recreated S3-Viking

for Parasite Drag comparison


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Validation and Verification.

S3 Aero

Data

Report

OpenVSP

Parasite

Drag

Percentage

Difference

CD0 0.01779 0.016926 -8.51%

• Did not model

pylons and cowls,

used base

geometry

• Total Data Report

CD0 comes to

0.01779


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API/Scripting Integration

• S-3 Viking Script Included with public release

– Example of how to change parameters and run Parasite

Drag analysis

• User has full access to all UI inputs through API

– All general options can be called through enumerators

(e.g. CF_TURB_IMPLICIT_KARMAN_SCHOENHERR)

– All table row inputs are found through the parent

geometry

– Or as part of AnalysisMgr


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Unit Tests and Visual Output

• Simple model

creation, analysis run,

option changes are all

tested through the

API

• S-3 Viking Model also

included as test

• All equation data

output to *.csv to be

displayed using

included Matlab script


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Units Tests and Visual Output


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Documentation

• Basic UI and usability

documentation within the

Parasite Drag Tool

• Reference length calculation

methods (body/wing)

• Partial turbulence friction

coefficient method

• Grouping

• Subsurface handling

• All friction coefficient and form

factor equations listed on wiki,

references included

• Visualization of data pulled

from unit tests


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Development Status

• What was presented last year?

– First draft of the Parasite Drag Tool

• What have been the major updates/improvements/fixes?

– Behind the scenes improvement efforts

– Inclusion of Subsurface handling

– Grouping

– Transonic (In development)

• When was it first released?

– Released in OpenVSP 3.12

• Who paid for the effort?

– Funded by AFRL SBIR Phase II


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DEMO/TUTORIAL


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Questions?


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Contact Information

Bryan Schmidt

[email protected]

[email protected]


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Transonic Drag Rise Tool

• Adds multiple table

options for transonic

drag rise for wing

geometries

• Transonic drag rise

is added to total

drag in main table

tab

Documents

1 VSP Workshop 2017 OpenVSP Parasite Drag Build Upopenvsp.org/wiki/lib/exe/fetch.php?media=workshop17:... · 2018-04-01 · NNX09CC86P SBIR Review, Presented to NASA, July 7VSP Workshop