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Errors with CHRONO file for VAWT

Hello,

My group is looking to use QBalde to analyze our VAWT design and allow us to extract forces to use as inputs into other simulations. After the Main and other files have been created, they were uploaded into QBlade and when it was used to try and create a turbine, we received errors. The errors read as:

Structural Model: assign properties for 4 bodies

Structural Model: trying blade properties

Structural Model: Problem assigning Beam Cross-Sectional Data! Structural Model Construction failed. Check the debug line above…

Structural Model: …to identify the structural properties (.str) file that caused the problem!

 

I have attached the Main and Blade input files below for you to reference.

 

If anyone can spot what may be causing this error, it would be of much help to our team. Let us know if you have any questions or need more information

 

Thank you.

 

 

 

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Hi Brian,

the first column in the blade properties table needs the nondimensionalized length position starting from 0.0 in the first line and ending at 1.0 in the last line. This position indicates at which location of the blade the respective properties should be assigned to the beam.

In your example you have a constant value in that column – thats why the file is not being imported.

Best,

David

Hello,

By changing the blade length properties to go from 0 to 1, I was able to create a turbine. Now when I use that turbine to try and run a simulation, it will not rotate at all. Is there something that I am missing that may cause this to happen? The downloadable Sandia VAWT works just fine and I can not spot any differences between Sandia’s and our structure files

If you can help, it would wonderful.

Thank you

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Hi Brian,

could you fix your issue? Otherwise, could you upload a .qpr file? This would be much more convenient than trying to reassemble the model from the structural files you attached. There can be many reasons why your model isnt working properly…

BR,

David

Here is the .qpr file that we have been working with

Here it is

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Hi Brian,

the issue with your structural model is that in your aerodynamic blade design the radial position of the first and last station of your blade is defined as zero.

With the BLDCONN keyword in your structural MAIN file you connected the rotor at exactly these positions with the torquetube. This causes issues during the creation of the structural model as some required vectors, to create the local blade coordinate system, cant be obtained when a structural blade node is exactly located on the central tower axis.

To fix this you should change the radial position to be larger than zero (even 1e-5m would be enough) at the location where the blade connects to the tower. Ideally you could choose the radius of the tower itself, in this way the blade would also not visually “poke” through the tower.

BR,

David

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