Aeroelastic analysis of Multi Rotor System

Hello everyone,

I need to study aeroelastic analysis over a multi-rotor system wind turbine; in order to optimize the weight of the supporting structure for the rotors.
I’m not an expert in FAST, just a regular user running some cases and very few modifications in the input files to FAST. However, this task needs major modifications;

  1. Changing the tower shape from simple tower to the complex supporting structure for multi rotors. As shown in example figure

  2. Add more than one rotor for the same simulation and attaching them to the tower.

  3. Define how the rotors interact with each other aerodynamically, to study the aerodynamic behavior when changing the distance between rotors.

  4. Define the yaw control for the whole system.

I would appreciate any guidance regarding this matter. As if there is a way to convert a CAD file of a multi-rotor wind turbine into twr and fst files for example. Can I only modify the input files for FAST, AeroDyn, …etc., Do I need to modify the source code to suit my problem?

Thanks in advance.

Best regards,
Amr Ismaiel

Dear Amr,

Without extensive modifications to the FAST source code, it is not possible in FAST to model a system with multiple rotors attached to the same tower. To model such a system would require you to (1) change the structural module (to model the specific multi-rotor configuration of interest), (2) allocate multiple instances of AeroDyn and ServoDyn (to model the aerodynamics and controls of each rotor), (3) possibly consider wake interactions between the rotors, etc. These changes are far beyond what I can explain in a forum post.

I suggest that you first familiarize yourself with the architecture of FAST to see if you have the time/interest/expertise to make these changes.

Best regards,