CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   STAR-CCM+ (http://www.cfd-online.com/Forums/star-ccm/)
-   -   Field Function for Surface Length (http://www.cfd-online.com/Forums/star-ccm/112114-field-function-surface-length.html)

badger1 January 22, 2013 09:43

Field Function for Surface Length
 
Does anyone know if there is a field function for the surface length. I wish to plot pressure coefficient vs surface length on an aerofoil rather than axial distance.

Thanks

ryancoe January 22, 2013 10:53

You may be able to do this with a combination of vector field functions.

Another approach would be to write a field function with a polynomial that gives the location of the surface as a function of the orthogonal coordinates, and then reference that.

badger1 January 26, 2013 07:22

what if the surface is just a random collection of points and not a quadratic curve or something like that. is there a way I could use the coordinates of it somehow?

Thanks

ryancoe January 27, 2013 11:03

What type of airfoil is it? You should be able to come up with a function for the surface based on this.

Alternatively, you could just fit a curve to the coordinates.

badger1 January 27, 2013 13:04

It is a turbine blade the geometry can be found here:
http://www-g.eng.cam.ac.uk/whittle/T106/Start.html
I dont think I will be able to use an equation to determine the points. Is there not function that will get the points out of the geometry used in Starccm and make them avaliable.

If I export the x and y coordinates of the geometry I can use excel to do it by finding the distance between each point and it gives a rough estimate I was just hoping that star would be able to do this for me

thanks

ryancoe January 27, 2013 13:12

If it were me, and there were no way of finding the function used to describe the blade geometry, I would export the points and use matlab to fit a function (probably a cubic spline) to the surface.

You should be able to export the points by creating a table with the boundary of interest (the airfoil surface).

rwryne January 28, 2013 02:05

I've requested this feature from cd-adapco as well.

If you have access to fieldview, they do have a method to do it.


STAR-CCM+ recently added in a "unwrapper" surface plot that is supposed to take a 3d surface and flatten it to 2d. Not sure if this could be used to flatten the surface out and then do a plot from that.

badger1 January 28, 2013 08:38

I do not have access to fieldview, is it a free program or would I need a licence.

Is Unwrapper only in the latest version of Starccm+ as I have 7.04.006 and when I search "unwrapper" in the help file nothing comes up

thanks

rwryne January 28, 2013 13:15

Quote:

Originally Posted by badger1 (Post 404496)
I do not have access to fieldview, is it a free program or would I need a licence.

Is Unwrapper only in the latest version of Starccm+ as I have 7.04.006 and when I search "unwrapper" in the help file nothing comes up

thanks

Fieldview requires a license.

Its in 7.04. Not sure if it will do what you want, Ive only glanced at it.

The help file page title is:

Unwrapping, Unrolling and Projecting with Transforms

Its under visualizing solution -> transformations


All times are GMT -4. The time now is 15:15.