Review NACA0012 2D Airfoil Model Autodesk® Simulation CFD™ Build your Simulation IQ! Review NACA0012 2D Airfoil Model Autodesk® Simulation CFD™ Royce Abel Sr. Product Support Specialist

Welcome to Autodesk Technical Support Webinar Series! Previous CFD Webinars Results Visualization (686 Views) Meshing Errors (848 Views) What’s new in CFD 2015 (1803 Views) CFD 2015 Install and License (811 Views) Turbulence Models (1691 Views) Rotating Regions (380 Views) API Programming (198 Views) Modeling a Sailboat (213 Views) NACA0012 Validation Progress Smoke modeling … Tentative for November Where do we announce? Autodesk CFD Forum Direct Emails Twitter - @ADSKSimulation Facebook - AutodeskSimulation LinkedIn - Computational Fluid Dynamics YouTube Channel: AutodeskSim360 – Build Your Simulation IQ Slide Deck : https://autodesk.box.com/cfd9

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? 

Today’s Agenda Inspiration NACA Airfoils NACA 0012 Current Progress?

Customer Driven Inspiration! Lift 15% Drag Over 6x “Is this really the best we can expect?” - Wolfgang http://forums.autodesk.com/t5/simulation-cfd/autodesk-simulation-cfd-naca0012-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 00XX NACA0012 on left and NACA 2412 on right which bends the camber line. 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)

Implementing the NACA0012 Airfoil Cessna 207 Skywagon : http://4.bp.blogspot.com/-Hc9lJPnisaI/TghkLTCRjCI/AAAAAAAADD4/O9mbhLNjNqU/s1600/CHL+NZQN+Mount+Cook+Airlines+D+White.jpg Inventor Geometry Show the eq driven airfoil profile Cover the trailing edge assumptions that are available

Review Geometry In Autodesk Inventor

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 Sensitivity: Mach: 0.05 – 0.36 Changed lift slope curve and maximum lift coefficient. Reynolds: 2 – 12E6 Little effect on lift-drag ratio min/max AOA: 0 – Max Lift Reynolds Sensitivity: Effects all parameters to some extent Correlation to Theory: Good trends as compared to Mach Poor rends as compared to Reynolds number Tripped results aligned theory and experiment Summary of Findings:

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: 10E4 – 10E7 AOA: 0 – 180°

Experimental Key Data Shedahl: Re = 2 x 10^6 Ladson: Re = 1.76 x 10^6

Assessment of Wind Tunnel Results for the NACA 0012 Airfoil 0° AOA A Critical Assessment of Wind Tunnel Results for the NACA 0012 Airfoil McCroskey (NASA Ames) 1987

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

What is the NACA 0012 CFD setup strategy? Effective layer factor is 336%

What is the NACA 0012 CFD setup strategy? Advanced Turbulence Meshing SST Flag Modifiers 60 Enhancement Layers use_sst_rc 1 mesh_enhance_thick (%): 400 sst_new_iwf 1 Layer Factor: 0.84 Updated Wall Calculator Airfoil Surface mesh: 2.5 mm resid_bdry_force_calc 1 First Region: 5 mm Effective layer factor is 336%

Why use the flag use_sst_rc Why use the flag use_sst_rc? Coandă Effect: Tendency for fluid jet to be attracted to a nearby surface 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.

What are the preliminary results?

Autodesk Simulation CFD Preliminary Results

What are some potential model Sensitivities? Mesh Number of Layers 60 30 15 Layer Factor 200% 400% 600% General Mesh Size 75% 100% 125% Mach 0.08 0.15 Solver Controls ISC On/Off Auto Startup On/Off No SST Flags (Wolfgang) ADV2 Convergence Default Tight Manual/Tight + 1, 2, and 3 extra order of magnitude Solver Controls ISC = ON Auto Startup = On ISC and Auto Startup = On No SST Flags ADV2 Convergence Default Tight Manual/Tight + 1 Order of Mag Manual/Tight + 2 Order of Mag Manual/Tight + 3 Order of Mag

Sensitivity Study @ 10° 10% 10% 15 Layers + 200 LF 1.007 0.01502 125% Tight 75% 1 Order 15L 10% 10%

Slide Deck : https://autodesk.box.com/cfd9