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kegiljarhus / pyBEMT

Implementation of the Blade Element Momentum Theory for turbines and propellers in Python
MIT License
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The difference between pitch and twist #8

Open HYB777 opened 1 year ago

HYB777 commented 1 year ago

Hi! I am confused about the parameter "pitch" and "twist".

In configuration file, if i understand correctly, the parameter "pitch" is the radical distribution of twist angle of each airfoil section.

And what about the parameter "twist"?

Another question is when I use custom airfoil, I compute in rotor mode, the efficiency would be negative or larger than 1, is it normal?

kegiljarhus commented 1 year ago

Twist is a global change in angle to the entire blade, on top of the pitch distribution. This is just to make it easier to do a sweep on this parameter, or use in a control setting. Note that this is parameter is not tested that much in the current version, so be careful with it.

It's hard to say what the issue with your airfoil is without more details, if you can share the airfoil file and your .ini file I can have a look at it.

HYB777 commented 1 year ago

Twist is a global change in angle to the entire blade, on top of the pitch distribution. This is just to make it easier to do a sweep on this parameter, or use in a control setting. Note that this is parameter is not tested that much in the current version, so be careful with it.

It's hard to say what the issue with your airfoil is without more details, if you can share the airfoil file and your .ini file I can have a look at it.

Here is an example of a helicopter rotor, which simulates the ascent of the helicopter. The details are descripted in readme file, thank you for your help! helicopter.zip