NNX09CC86P SBIR Review, Presented to NASA, July 7 th , 2009 VSP Workshop 2017 Aug. 30 th – Sep. 1 st 1 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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NNX09CC86P SBIR Review, Presented to NASA, July 7th, 2009VSP Workshop 2017 Aug. 30th – Sep. 1st
1
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
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
Introduction
Goal
• Reduce the time it takes to complete a
parasitic build up for conceptual aircraft
utilizing OpenVSPs’ internal geometry
calculations
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
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
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
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
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
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
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
Order of Operations
1
Add and Edit Geoms
Edit Options as Desired
2
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
Order of Operations – Cont.
2a 2bAdd Excrescence Edit Excrescence
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
Order of Operations – Cont.
3
Options as Desired
4
Calculate CD0 or Export to CSV
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
Order of Operations – Cont.
• 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
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
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
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
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
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
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