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yusoff March 6, 2001 01:36

reading data from model
Hi all ...

I would like to read data (pressure) from the airfoil using cfx5.4. now what i do is i will plot a polyline which i got the point from the book then export data on the polyline. for incidence other than 0, i will have to get the points from excel .... so far it works .... however i fear that the point produced by excel would not be on the real surface ... hence producing error. could somebody who have other method than mine .... which of course more accurate .... let me know how to take the reading off the surface.

thanks a lot for your time.

Yiu March 6, 2001 02:52

Re: reading data from model
Hi yusoff

It is TIM here (the guy in CFD lab with you). I don't know other method to extract result from the surface however, as I know Excel can get very accurate data from your data files (at least, can up to 8 decimal place).

Indeed, I want to ask you one question. You plot your graph in Cp vs Distance, something likes that. (Cp: Coefficient of Pressure on the surface.) How can you get Cp from CFX5-vis???

Regards TIM

Darcy March 7, 2001 06:18

Re: reading data from model
It takes much time to read datas from CFX output files. Try to use utilities in your own post-processing software. For example, the line plot function in some post-processing software not only help you extract the datas along specific curves or lines but plot the data curves and export numbers to a data file.

The second method I suggest is using USRPRN. You can open a file and write datas in it.

Dan Williams March 20, 2001 00:12

Re: reading data from model
You can use an algebraic additional variable to calculate Cp. Here's some CEL that will likely work, I think ;-).

pinf = 101325 [Pa] speedsq = u^2+v^2+w^2 Cp = (p - pinf) / 0.5 [] * density * speedsq

pinf can be whatever pressure you want to use, even zero I suppose.

Just export Cp along your polyline in visualise. Should work just fine.


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