create shear stress formula

[altenbach · Accepted solution]

---

mechen wrote:

What do you mean about plain LabVIEW solution? Could you please give an example vi about this? Thanks again.

---

Maybe something like this?

[mechen]

Hi altenbach,

Thanks for your solution. I will try this in the lab on Wednesday and give an information about it. Thanks a lot again. 

[mechen]

Hi altenbach,

I also want to construct a matrix of [13x5001] as a result of 13 run (in each run 5000 data are taken) in the same vi. The data in the first column are constants of radial positions.

After obtaining the matrix, I want to draw the curve for the data in the second, third and so on 5000th column with respect to radial positions in the first column.

And then fit an equation to each curve as u(r) and then multiply the equation again by r variable and the integrate it; int[u(r)*r*dr] So for each column, one mean value will be found and;

The matrix will reduced to [1x5000] eliminating also the first column values of radial positions.

Then the 5000 mean data in [1x5000] matrix will be fitted to the sinusoidal equation of

u_mean(t)= u_ta *u_os*cos(2*pi*freq.*t)

where u_ta and u_os are constants that will be found as a result of this fitting.

I have tried to do all these for about one month, but I failed.

I also write the procedure in the attached vi as notes. Could you please help me again? Thanks a lot.

[mechen]

Hi altenbach,

Could you please help me to construct the matrix that I mentioned previously? I have tried to construct but failed. Please help. Thanks a lot.

[mechen]

Hello everyone! 

I want to write real-world data into matrix rows or array rows for each of 13 run and then process data in each column of matrix or array. 

I want to construct a matrix of [13x5001] as a result of 13 run for different radial positions (in each run 5000 data are taken) in the same vi. The data in the first column are constants of radial positions. 5000 data related to each radial positions will be written in the corrseponding row of matrix or array.

The array or matrix will be like that given in sample vi block diagram.

After obtaining the matrix, I want to draw the curve for the data in the second, third and so on 5000th column with respect to radial positions in the first column.

And then fit an equation to each curve as u(r) and then multiply the each one of 5000 equations again by r variable and then integrate it; int[u(r)*r*dr] So for each column, one mean value will be found and;

The matrix will reduced to [1x5000] eliminating also the first column values of radial positions.

Then the 5000 mean data in [1x5000] matrix will be fitted to the sinusoidal equation of

u_mean(t)= u_ta *u_os*cos(2*pi*freq.*t)

where u_ta and u_os are constants that will be found as a result of this fitting.

I have tried to do all these for about one month, but I failed.

I also write the procedure in the attached vi as notes.

Is there anyone who can help me? Could you please help me? Thanks a lot.

[Paul-D]

mechen,

This is Paul from Applications Engineering at NI.

I am going to try and give you some pointers that will help with the construction of your program.

First, check out this document:  http://zone.ni.com/reference/en-XX/help/371361G-01/lvconcepts/using_matrices/    .  It provides a lot of information on matrices.

Second, I recommend using the power of for loops and their ability to auto index data, especially in nested for loops, which allow you to work with each dimension:  http://zone.ni.com/devzone/cda/tut/p/id/7588

I am attaching a very simple example of what I'm referencing.

This seems like a pretty complicated problem you are working on, it may exceed the generosity of our forum members.  You may want to enlist the help of our Alliance members:  http://www.ni.com/alliance/

Good luck,

Paul

[mechen]

Hi Paul,

Thank you for your reply. I want to see your attached vi but cannot open. Because, I have 2009-SP1 version. Could you please save as 2009-SP1 and send again.

Also, I want to ask what you mean saying Alliance members to help.

I think I can not construct the subvi that I want to do. Because I am a new user and the vi that will be constructed seems to be very complicated for me, for a new user.

Could you please help me more? I am too late to complete my thesis. After finishing the pogram, I will take my data. But, if I try more trials on preparing this subvi I will be too late. Please more help!

Or is there anyone who can help me more to construct this subvi?

Thanks a lot.

[mechen]

Hi altenbach,

Could you please help me for my request? I will be too late if I try more trials to construct. I am a new user and this subvi is very vital for me to begin to take data and complete my thesis. The time goes out, but I cannot do any more.

I think you can help me to construct it.Please help!

Thanks a lot.

[Paul-D]

mechen,

I have re-saved my VI for LabVIEW 2009 in this post.

Alliance members probably won't be an option to you, now that I see you are working on a thesis.  They are NI approved for-pay support that can assist in coding and hardware implementation.

Unfortunately, I can not help you directly code this.  I am only allowed to provide tutorials and examples, and help people edit their code if it contains errors.  Anything beyond that is left up to the geneorisity of the community.

If you want further help, I would suggest you break the code into more manageable chunks and see if you can bridge the difference between what people can help you with, and what you can figure out on your own.  Also http://www.ni.com contains some great tutorials, examples and sample code.  Our developer zone has over 9000 examples of code.

Paul

[mechen]

Hi altenbach,

Could you please help me for my previous result? I found no way out. Please help!!