Hi,
I conducted a beta variation analysis using the T5 beta polars in XFLR5. The graph shows that the cl-beta curve has a positive slope. But the clb derivative from the T7 Stability analysis shows that the clb is negative. May I know why this happens and which one should I consider as the actual cl_beta.
Reneesh S
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For historical reasons linked to the development and to the different axes conventions, the signs of lateral derivatives may not be totally consistent in xflr5. I don't plan to change them however because it would require a considerable code ovehaul which I'm not willing to do right now.
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The orders of magnitude of ther T5 polars look good as far as I can tell and are consistent with the results of both flow5 and AVL.
The signs of Cn and Cl in xflr5 are wrong.
flow5 is OK https://flow5.tech/docs/flow5_doc/Validation/Stability.html
Last edit: André 2024-03-04
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi,
I conducted a beta variation analysis using the T5 beta polars in XFLR5. The graph shows that the cl-beta curve has a positive slope. But the clb derivative from the T7 Stability analysis shows that the clb is negative. May I know why this happens and which one should I consider as the actual cl_beta.
Reneesh S
For historical reasons linked to the development and to the different axes conventions, the signs of lateral derivatives may not be totally consistent in xflr5. I don't plan to change them however because it would require a considerable code ovehaul which I'm not willing to do right now.
Even the magnitudes are not consistent. Is this rectified in flow5?. Any suggestion if I can use the lateral coefficient slopes from the graph?
The orders of magnitude of ther T5 polars look good as far as I can tell and are consistent with the results of both flow5 and AVL.
The signs of Cn and Cl in xflr5 are wrong.
flow5 is OK https://flow5.tech/docs/flow5_doc/Validation/Stability.html
Last edit: André 2024-03-04