CFD Online Discussion Forums - import data from CFX-post to MATLAB/EXCEL

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)

- CFX (https://www.cfd-online.com/Forums/cfx/)

- - import data from CFX-post to MATLAB/EXCEL (https://www.cfd-online.com/Forums/cfx/23856-import-data-cfx-post-matlab-excel.html)

import data from CFX-post to MATLAB/EXCEL

hi, can u give the procedure to import the data from CFX-post to MATLAB/EXCEL to plot the graph & do the calculation.

Re: import data from CFX-post to MATLAB/EXCEL

Create a graph on the CFX post, and when you decide what you plotted, there is a button that says EXPORT.

Re: import data from CFX-post to MATLAB/EXCEL

1. You can do it the way Sze Hong says, by plotting the chart and then exporting

2. Or once you have created your point/line of interest. Just press file ---> export--- in csv format, and you have it in EXCEL. ( You cannot export transient results this way though, i think)

Then if you want, you can import your values from excel to MATLAB easily.

what is the procedure to find coefficient of lift

what is the procedure to find the coefficient of lift from velocity vs chord length graph? or pressure vs chord length graph?

Hi guys,

I need help on this too. I have transient run in which i would like Matlab to graph the location of a moving body (X,Y,Z), along with the forces and moments acting on it. So far, I've set up the monitor plots in which the data is stored in *.out files for each time step.

The data sitting in front of me on screen, however I haven't the clue to how to graph them out using Matlab, e.g. Collating them into one data file for plotting or reading the values from each .out file as it plots the graph.

Edit: Just to clarify what i mean is through script rather than manually (e.g. using the mouse) in Matlab.

I use the export function to export the results in a .csv file. You have to set a location from which it exports the results, so it is always recommended to view the results first in a chart and then export them to a .csv file. Make sure you don't add the header, you can unselect it on the second tab of the export screen, otherwise you have to manually set the rows and columns of the data for Matlab to work.

Use csvread in Matlab to load the results in your workspace. You can check 'help csvread' on how to do that.

Cheers!

Thanks, Kartus. I've managed to do as you've suggested

Results_002 = csvread ('Analysis_Results_002.dat',1,0);

It would have been good to have the labels read, would save me time to manually include them in the plot, e.g.

Timestep = Results_001(:,1);
Mesh_Quality = Results_001(:,2);
Sphere1_Force_X = Results_001(:,3);
Sphere1_Force_Y = Results_001(:,4);
Sphere1_Force_Z = Results_001(:,5);
Sphere1_Moment_K = Results_001(:,6);
Sphere1_Moment_M = Results_001(:,7);... and so on

To my knowledge it is not possible to read anyhting else then values from a csv file using csvread.

I can't help you with the labels, I add all the labels manually in an m-file and load all the results for different cases from that file. It is a copy-paste solution, not very elegant...

hello. i have a question about this . when i export to .csv file and opens it with excel . the data are in different rows and just one column .for example x1 and v1 are in first column i want to be x1 in fist and v1 in second column . how can i do it . thanks for help .:(:confused:

This is really not a CFX issue, but here goes...

It would be something like:
Data/From text/<find your file>/Delimited/<next>/Delimiters: comma/<finish>

Quote:

Originally Posted by Lance (Post 411367)

This is really not a CFX issue, but here goes...

It would be something like:
Data/From text/<find your file>/Delimited/<next>/Delimiters: comma/<finish>

thank you .. i did it .

Hello,

I know this thread is very old, but I might have the same issue: I have several defined points

(like 100 or so), several reference temperatures (one for each point). For each point, a heat transfer coefficient is computed using the formula:

$h(P_i)=\frac{Wall\ Heat\ Flux\ (P_i)}{\text{Reference Temperature}\ (P_i)-300[K]}$

What interests me is the weighted average of these HTC's (therefore I cannot use the "monitor point method"):

$h_\text{total}=\frac{\sum_iA_ih(P_i)}{\sum_iA_i}$

This value only depends on time:

$h_\text{total}=h_\text{total}(t)$

I want to export the datas $( \text{time step} , h_\text{total} (\text{time step}))$ to MATLAB. For this purpose, I need the .csv file. Thing is, as far as I know, we can do that with the "export" command in CFX Post only for a given time step.

But I have the chart $h_\text{total}=h_\text{total}(t)$ plotted. Is there a way to get the .csv file direct from the chart?

Or do I have no other choice but to write some script to loop over the time steps to retrieve for each one of them the value of $h_\text{total}(\text{time step})$ ?

I finally managed to do what I wanted to, that is, to get a .csv file with the time (in my case variable name = TimeVar) and the value of $h_\text{tot}$ (in my case variable name = AAlphaGesVar) for each time. This might interest someone, so I describe what I did (I learnt a bit of Perl too):

data.csv looks like this:

Code:

9.89989028e-004, 5.02314758e+000

1.02000998e-003, 5.10743713e+000

1.05003000e-003, 5.00016737e+000

1.07995002e-003, 4.82792759e+000

1.10997004e-003, 4.82947874e+000

...

To get this .csv file I wrote this .cse file:

Code:

COMMAND FILE:

CFX Post Version = 16.0

#Enter your version of CFX Post here

END



!use strict;

!use warnings;



!open (OUTFILE, ">", "data.csv");





!for (my $i=34; $i<=169; $i++)

!{

# Start for loop to load different time step

# One need to modify it based on his/her need



!my $resstp=$i;

DATA READER:DATA READER

Current Timestep = $resstp

END

> load



EXPORT:

# export data to test1.csv

ANSYS Export Data = Element Heat Flux

ANSYS Reference Temperature = 0.0 [K]

ANSYS Specify Reference Temperature = Off

ANSYS Supplemental HTC = 0.0 [W m^-2 K^-1]

BC Profile Type = Inlet Velocity

Export Connectivity = Off

Export Coord Frame = Global

Export File = test1.csv

Export Geometry = Off

Export Node Numbers = Off

Export Null Data = Off

Export Type = Generic

Export Units System = Current

Export Variable Type = Current

Include File Information = Off

Include Header = Off

# One can turn header off if it is wanted

Location List = P22

#The value of my variables does not depend on the location, so I put any point here, just modify it based on your need

Null Token = 0

Overwrite = On 

# One should turn the Overwrite On

Precision = 8

Separator = ", "

Spatial Variables = X,Y,Z

Variable List = TimeVar, AAlphaGesVar

Vector Brackets = ()

Vector Display = Scalar

END

>export



!open (INFILE, "<", "test1.csv");

!print OUTFILE <INFILE>;

# copy data in test1.csv to output file, which is data.csv

!close INFILE;

!}

!close OUTFILE;

adapted from the script http://www.eureka.im/3771.html

Under CFX Post I clicked on "Session" then on "Play Session" and selected the .cse file. After a couple minutes the file data.csv was written.

Quote:

Originally Posted by Darren Leong (Post 309273)

I know this is an old thread, but I am trying to do something very similar.

How did you manage to get all your required variables into one dat file so that matlab can read it? When I export data to a csv from CFD-post, it only writes one data series, as oppose to the 36 that I need