Project 4 : Viscous Effect How to use XFOIL

[associated with NotesPJ4.txt] EAE127

Download XFOILhttp://web.mit.edu/drela/Public/web/xfoil/

Part I.Run XFOIL and type naca0012

type ‘gdes’ to plot profile and ‘hard’ to output plot.ps

type ‘return key’ to exit from ‘gdes’ routine. Type ‘quit’ to close XFOIL

You can see the list of operation by typing c> ?

Rename plot.ps ex) naca0012profile.ps and double click naca0012profile.ps

CAE lab. has GSview and you can hard copy it

by ‘Alt’+ ‘Print Screen’

Download s1223.dat from class web. Run XFOIL and type

‘load s1223.dat’ Then repeat ‘gdes’ to output the

geometry

Part II. a Run XFOIL (inviscid) type: ‘naca0012’, ‘oper’ to enter the

calculation mode and solve 0 incidence solution. Type ‘alfa 0’.

Repeat several times to type ‘alfa 0’ if the PltLib window doesn’t show the plot well.

Run : alfa=0 to -20 in steps of 5 deg.

and write the CL and CDp from the screen.

Re-calculate alfa=0 solution and run 0 to 20 deg.

b.& c. Viscous polar calculation Run XFOIL type:’naca0012’, ‘oper’ then type ‘visc’ to enable viscous mode. type: 300000 for Re #. Prompt changes to .OPERv>

Specify output file name.Type: pacc

Specify 2 file names for example,

polar_naca0012_300e3.dat

Dump_naca0012_300e3.dat.

Now files are opened.

Screen tells ‘polar accumulation enabled’

Calculate alfa 0 case for an initial solution. Calculate from this solution, alfa 0, over the given range of incidence in steps of 1 deg. If the code doesn’t converge, about 14 deg., you will have to moving in 0.5 deg to get convergence.

sequence run option

Instead of using a single calculation by specifying alfa, there is a sequence command. The following command run from alfa 0 to -13 in steps of alfa -1.

OPERv> aseq 0 -13 -1

d. PlottingDownload the Pplot from the XFOIL webpage.

You can plot polar from your output data as well.

Run Pplot. Type 1 and type polar file name you output by XFOIL. Then type ‘enter key’

Type 4 to output the polar plot. Type 0 to close pplot. Rename the plot.ps to different name.ps double click the ps file to open by the GSview. Save the plot by screen dump, ‘Alt’ + ‘Print Screen’

2.d Plot boundary layer parameters

As we did in 2.b and 2.c, run specified case in viscous mode. For example,

>naca0012

>oper

>visc

>1000000

>alfa 0

Then type

>?

You find Vplo as BL variable plot.

Type vplo and type > ? to see a list of variables

Type ‘cf’ and type ‘hard’ to save the plot. Copy and past the plot.ps in different name. (Program is using the file and cannot rename it.) Repeat ‘dt’ for upper surface Repeat ‘db’ for lower surface Repeat ‘h’ for the form factor

*δ Θ

H*δ Θ

Plot everything by excel or Matlab

• If you like to plot from data files, type ‘dump’ and specify the filename to obtain the data files.