Build your Simulation IQ Review NACA 0012 2

Welcome to Autodesk Technical Support Webinar Series! Previous CFD Webinars Where do we announce? 1. Results Visualization (686 Views) 2. Meshing Errors (848 Views) 3. What’s new in CFD 2015 (1803 Views) 4. CFD 2015 Install and License (811 Views) 5. Turbulence Models (1691 Views) 6. Rotating Regions (380 Views) 7. API Programming (198 Views) 8. Modeling a Sailboat (213 Views) 9. NACA 0012 Validation Progress 10. Smoke modeling … Tentative for November § § § Autodesk CFD Forum Direct Emails Twitter - @ADSKSimulation Facebook - Autodesk. Simulation Linked. In - Computational Fluid Dynamics You. Tube Channel: Autodesk. Sim 360 – Build Your Simulation IQ © 2014 Autodesk Slide Deck : https: //autodesk. box. com/cfd 9

September CFD Support Knowledge Articles knowledge. autodesk. com Week One: How to access Autodesk Simulation product help pages How to update the geometry in Simulation CFD The effects of refinement region on flow in Simulation CFD Week Two: Temperature values revert to default when attempting to map thermal results from Simulation CFD to S. . . Week Three: How to free up disk space for Autodesk Simulation Flex How to set temporary files location for Simulation Job Manager How to set up a material to include transmissivity and reflectivity Volume flow rate in a valve analysis does not correlate with hand calculations Week Four: Adding a new design to my project is causing the interface to crash How to calculate the number of air changes in a room Why is Simulation CFD not using all of the available RAM? © 2014 Autodesk

Today’s Agenda Inspiration NACA Airfoils NACA 0012 Current Progress? © 2014 Autodesk

Customer Driven Inspiration! Lift 15% Drag Over 6 x “Is this really the best we can expect? ” - Wolfgang © 2014 Autodesk http: //forums. autodesk. com/t 5/simulation-cfd/autodesk-simulation-cfd-naca 0012 -benchmark-test/td-p/5228183

What are NACA Airfoils? § NACA – National Advisory Committee for Aeronautics § Numerical code system developed to precisely generate airfoil cross-sections of various shapes and complexity. § Today’s Focus: 4 -Digit NACA Symmetrical Airfoil 00 XX c: Chord length, x: Position along the chord from 0 to c y: Half thickness at a given value of x t: Maximum thickness as a fraction of the chord (XX/100) © 2014 Autodesk

Implementing the NACA 0012 Airfoil © 2014 Autodesk

Review Geometry In Autodesk Inventor © 2014 Autodesk

Experimental Results for NACA 0012 Effects of Independent Variation of Mach and Reynolds Numbers on the Low-Speed Aerodynamic Characteristics of the NACA 0012 Airfoil Section – Charles Ladson (NASA Langley 1988) Key Testing Points: § Mach: 0. 05 – 0. 36 § Reynolds: 2 – 12 E 6 § AOA: 0 – Max Lift Summary of Findings: § Mach Sensitivity: § § Changed lift slope curve and maximum lift coefficient. Little effect on lift-drag ratio min/max § Reynolds Sensitivity: § Effects all parameters to some extent § Correlation to Theory: § § § © 2014 Autodesk Good trends as compared to Mach Poor rends as compared to Reynolds number Tripped results aligned theory and experiment

Experimental Results for NACA 0012 Aerodynamic Characteristics of Seven Symmetrical Airfoil Sections Through 180 -Degree Angle of Attack for Use in Aerodynamic Analysis of Vertical Axis Wind Turbines – Robert Shedahl (Sandia 1981) Key Testing Points: § 7 Airfoils Sections § Reynolds: 10 E 4 – 10 E 7 § AOA: 0 – 180° © 2014 Autodesk

Experimental Key Data Shedahl: Re = 2 x 10^6 Ladson: Re = 1. 76 x 10^6 NACA 0012 Lift Coefficient NACA 0012 Drag Coefficient 0. 040 1. 5 0. 035 Drag Coefficient Lift Coefficient 0. 030 1. 0 Shedahl - Smooth Ladson - 60 -W Grit Ladson - 80 -W Grit 0. 025 0. 020 0. 015 0. 010 0. 005 0. 000 0. 0 0 2 4 6 8 10 Angle of Atttack (°) © 2014 Autodesk 12 14 16 18 20 22 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20 22 Angle of Atttack (°)

Assessment of Wind Tunnel Results for the NACA 0012 Airfoil 0° AOA © 2014

Assessment of Wind Tunnel Results for the NACA 0012 Airfoil 0° AOA With Autodesk Simulation CFD Result © 2014 Autodesk A Critical Assessment of Wind Tunnel Results for the NACA 0012 Airfoil Mc. Croskey (NASA Ames) 1987

What is the NACA 0012 CFD setup strategy? © 2014 Autodesk

What is the NACA 0012 CFD setup strategy? § Advanced Turbulence § SST Flag Modifiers § § use_sst_rc 1 sst_new_iwf 1 § Updated Wall Calculator § resid_bdry_force_calc 1 © 2014 Autodesk § Meshing § § § 60 Enhancement Layers mesh_enhance_thick (%): 400 Layer Factor: 0. 84 Airfoil Surface mesh: 2. 5 mm First Region: 5 mm

Why use the flag use_sst_rc? Coandă Effect: Tendency for fluid jet to be attracted to a nearby surface © 2014 Autodesk Numerical Study Comparing RANS and LES Approaches on a Circulation Control Airfoil Rumsey (NASA Langley)

Why use the flag sst_new_iwf? K-omega SST Slip Wall Formulation Enables a more accurate method of solving for the pressures and velocities and temperature near walls in conjunction with the SST turbulence model. © 2014 Autodesk

What are the preliminary results? © 2014 Autodesk

Autodesk Simulation CFD Preliminary Results NACA 0012 Lift Coefficient NACA 0012 Drag Coefficient 0. 050 1. 5 0. 040 Drag Coefficient Lift Coefficient 1. 0 0. 5 Sim. CFD - Re 1760000 0. 030 Shedahl - Smooth Ladson - 60 -W Grit 0. 020 Ladson - 80 -W Grit 0. 0 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20 22 0. 010 -0. 5 -6 -1. 0 Angle of Atttack (°) © 2014 Autodesk -4 0. 000 -2 0 2 4 6 8 10 12 Angle of Atttack (°) 14 16 18 20 22

What are some potential model Sensitivities? Mesh Mach Number of Layers 60 30 15 Layer Factor 200% 400% 600% General Mesh Size 75% 100% 125% 0. 08 0. 15 Solver Controls ISC On/Off Auto Startup On/Off No SST Flags (Wolfgang) ADV 2 Convergence Default Tight Manual/Tight + 1, 2, and 3 extra order of magnitude © 2014 Autodesk

Sensitivity Study @ 10° NACA 0012 Lift vs. Drag 0. 25 Default 0. 022 0. 20 Drag Coefficient 0. 020 0. 15 ADV 2 Ladson - Smooth Ladson - 60 -W Grit 0. 018 Ladson - 80 -W Grit Shedahl 0. 016 125% 75% 0. 10 Tight 1 Order Convergence 0. 05 15 L 0. 012 0. 00 0. 700 0. 800 0. 900 1. 000 Lift Coefficient © 2014 Autodesk 1. 100 10% 1. 200 0. 010 0. 970 Mach Solver 0. 014 10% Meshing 0. 990 1. 010 Lift Coefficient 1. 030 1. 050