VSP Workshop 2017 OpenVSP Parasite Drag Build Up

Transcription

1 1 VSP Workshop 2017 OpenVSP Parasite Drag Build Up Presented by: Bryan Schmidt Empirical Systems Aerospace, Inc. Work Support By: AFRL SBIR Phase II

2 2 Introduction Goal Reduce the time it takes to complete a parasitic build up for conceptual aircraft utilizing OpenVSPs internal geometry calculations

3 3 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

4 4 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

5 5 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 Body: Covert 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

6 6 Order of Operations Add and Edit Geoms 1 Edit Options as Desired 2

7 7 Order of Operations Cont. 2a Add Excrescence 2b Edit Excrescence

8 8 Order of Operations Cont. 3 Options as Desired Calculate C D0 or Export to CSV 4

9 9 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 C D0 If Geoms are added, everything is cleared and must calculate again 5 Final Results

10 10 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

11 11 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

12 12 Validation and Verification. Using Technical Report Data for Dimensions, recreated S3-Viking for Parasite Drag comparison PARASITE DRAG BUILD UP DATA Mach Altitude (ft) Vinf (ft/s) S_ref (ft^2) Temp ( F) Pressure (lbf/ft^2) Density (slug/ft^3) Lam Cf Eqn Blasius Turb Cf Eqn 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 Hoerner Wing_ Hoerner Wing_ Hoerner Fuse Hoerner Streamlined Body Fuse_ Hoerner Streamlined Body H-Tail Hoerner H-Tail_ Hoerner H-Tail_ Hoerner V-Tail Hoerner V-Tail_ Hoerner Excrescences Miscellaneous Count (10000*CD) Cowl Boattail CD Geometry Sub-Total: Excrescence Sub-Total: Totals:

13 13 Validation and Verification. Did not model pylons and cowls, used base geometry Total Data Report C D0 comes to S3 Aero Data Report OpenVSP Parasite Drag Percentage Difference C D %

14 14 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

15 15 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

16 16 Units Tests and Visual Output

17 17 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

18 18 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

19 19 DEMO/TUTORIAL

20 20 Questions?

21 21 Contact Information Bryan Schmidt

22 22 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