Simulation of turbulent airfoil Flow Using FlowLab 1.1 (CFD PreLab 2) Tao Xing and Fred Stern IIHR—Hydroscience & Engineering 100 Hydraulics Laboratories The University of Iowa 57:020 Mechanics of Fluids & Transport Processes http://css.engineering.uiowa.edu/~fluids/ Dec 2, 2003

Outline Assignments for CFD PreLab2 and Lab2 What data you need prepare before coming to CFD Prelab2 and Lab2? Detailed tutorial for simulating turbulent flow around airfoil using FlowLab 1.1 Other FlowLab functions Data need to be saved for CFD report

Assignments for PreLab2 and Lab2 CFD PreLab2: 1. Run FlowLab using same conditions in EFD Lab 3. 2. Validate FlowLab predictions(pressure and lift coefficients) with EFD measurements 3. Inviscid flow vs. viscous flow CFD Lab 2: 1. Parametric studies: effect of angle of attacks, effect of turbulent models, and effect of meshes.

Data need to be ready before PreLab 2 and Lab 2 EFD3 report, or EFD data: 1. Angle of attack 2. Chord length of the foil 3. Inlet velocity (or Re) 4. Air properties 5. Pressure coefficient distribution 6. Lift and drag coefficient A floppy disk to save documents or figures Slides 5~21 show a tutorial example

Tutorial Simulation conditions: 1. Foil: Clarky airfoil 2. Chord length: 1 foot (0.3048m) 3. Angle of attack: 12 degree 4. Domain: C type domain 5. Fluid properties: air at 22.4 degree, density: 1.1949 kg/m^3 viscosity: 1.8320e-5 kg/m.s 6. Inlet velocity: 7.04 m/s 7. Turbulent model: k-epsilon 8. Medium mesh 9. Double precision

FlowLab interface CFD process 1~6 CFD process: step 1, Geometry Sketch window

CFD process: Step 1, Geometry Units, SI recommended Reset values to default ones Create Geometry Go to CFD process, step 2 You are required to input the minimum parameters to create the geometry

CFD process: Step 1, Geometry Geometry Created

CFD process: Step 2, Physics

CFD process: Step 2, Physics

CFD process: Step 2, Physics(BCs details) Use uniform flow at inlet Use default values

CFD process: Step 2, Physics(BCs details)

CFD process: Step 3, Mesh

CFD process, step 4, Solve Stop the calculation to see intermediate results Time history of residuals Calculation will stop if either of the two parameters satisfied

CFD process, step 5, Reports

CFD process 5, reports (import EFD)

Reports (examples of results)

CFD Process, step 6, Post-Processing (Contours) Choose the contour variables

CFD Process, step 6, Post-Processing (streamlines)

CFD Process, step 6, Post-Processing (vectors) Choose appropriate scale to view velocity vectors

EFD data format for FlowLab (title "Pressure coefficient") (labels "Position" "pressure coefficient") ((xy/key/label "experimental") 0 -0.526354204 0.00381 -1.670297341 0.00762 -1.880839023 0.01524 -1.880839023 0.02286 -1.775568182 0.03048 -1.621170949 0.04572 -1.438701491 0.06096 -1.291322314 0.09144 -1.221141754 0.12192 -0.708823662 0.1524 -0.652679213 0.18288 -0.505300036 0.21336 -0.385993083 0.24384 -0.217559738 0.27432 -0.098252785 0.27432 0 0.24384 -0.007018056 0.21336 0.03509028 0.18288 0.021054168 0.1524 0.063162504 0.12192 0.112288897 0.09144 0.147379177 0.06096 0.224577794 0.04572 0.245631962 0.03048 0.273704186 0.02286 0.315812522 0.01524 0.449155587 0.00762 0.603552821 0.00381 0.870238951 ) Replaced with your own EFD data!

Other functions Fit the view to full size Align the geometry with coordinates

Other functions

Data need to be saved for report CFD PreLab2: 1. time history of residuals (residuals vs. iteration number), 2. pressure and lift coefficients (both CFD and EFD); 3. contour of pressure (CFD), 4. contour of velocity, 5. velocity vectors(CFD), 6. streamlines Detailed instructions, see assignments in Lab documents