Search found 45 matches

by Mark.Spring
Fri Mar 07, 2014 8:19 am
Forum: Computer-Aided Engineering Software Tools
Topic: Structural Modal Frequencies
Replies: 1
Views: 1434

Structural Modal Frequencies

This is a very basic question, but I was going to check that the structural frequencies of my FAST model were similar to the model I am trying to reproduce, but I was surprised that the frequencies of tower and blades are not explicitly input. The frequencies and mode shapes are calculated in BModes...
by Mark.Spring
Fri Sep 13, 2013 5:47 am
Forum: Computer-Aided Engineering Software Tools
Topic: Platform Properties
Replies: 21
Views: 13895

Re: Platform Properties

Dear Jason, The thread above relates to a symmetrical floating platform. I am investigating the feasibility of representating an assymmetric platform in FAST. We are considering building a model of a wind turbine on a floating platform in which the tower interace is offset horizontally from both the...
by Mark.Spring
Fri Aug 30, 2013 8:20 am
Forum: Computer-Aided Engineering Software Tools
Topic: Pre-Bent Blades
Replies: 1
Views: 3703

Pre-Bent Blades

As they have become longer and more flexible, many commercial blades have been designed pre-bent (in the flap-wise direction) in order to avoid tower strikes. I have been trying to find a relevant posting on this forum. If you know of one, can you post a link here? I suspect that the modifications t...
by Mark.Spring
Thu Jul 04, 2013 9:59 am
Forum: Computer-Aided Engineering Software Tools
Topic: Questions about the HydroDyn Module
Replies: 35
Views: 13230

Re: Questions about the HydroDyn Module

I am running FAST 7.01. FAST crashed. I have traced the error back to a call to the function Catenary in which the allocatable array LNodesX was not allocated and therefore could not be indexed. This was because the integer variable LineNodes was set to zero by default in FAST_Mods. There is also a ...
by Mark.Spring
Fri Mar 15, 2013 5:58 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST and wind loads on tower
Replies: 43
Views: 16564

Re: FAST and wind loads on tower

The idea was to ensure that the local element of interest was above ground level before calculating aerodynamic drag loads.
by Mark.Spring
Wed Feb 27, 2013 11:04 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST and wind loads on tower
Replies: 43
Views: 16564

Re: FAST and wind loads on tower

Dear Jason, I have written a new subroutine CalcAerDrag in FAST, which calls a new subroutine TwrAeroDrag in AeroDyn to compute aerodynamic drag forces on the tower. I have been testing FAST with an onshore turbine (NREL 5MW) and subsequently with an offshore turbine on a monopile (NREL 5MW). I have...
by Mark.Spring
Thu Jan 10, 2013 5:57 am
Forum: Computer-Aided Engineering Software Tools
Topic: Instructions for Compiling FAST
Replies: 246
Views: 128630

Re: Instructions for Compiling FAST

you could also try 1. editing the DOS batch file and deleting all the lines below (and including) the call to ifort. 2. submit the call to ifort directly from the DOS command prompt (a) you would copy the whole line (as below) from a text file containing the DOS batch file (or copy from this posting...
by Mark.Spring
Thu Jan 10, 2013 5:52 am
Forum: Computer-Aided Engineering Software Tools
Topic: Instructions for Compiling FAST
Replies: 246
Views: 128630

Re: Instructions for Compiling FAST

Dear Ramzan, I have just checked and you are right, if you try to redirect the output from the DOS batch file, you only get the first few lines and then the rest are sent to the DOS command windows as per usual. However, if I change the call to ifort within the DOS batch file, the output lines are a...
by Mark.Spring
Thu Jan 10, 2013 5:40 am
Forum: Computer-Aided Engineering Software Tools
Topic: Instructions for Compiling FAST
Replies: 246
Views: 128630

Re: Instructions for Compiling FAST

I have just found a setting for the DOS command window which controls "screen buffer size". Could you try to increase the "height" and see if the window can be made big enough for all the output? 1. Right click with the mouse on the blue ribbon at the top of the DOS command windo...
by Mark.Spring
Thu Jan 10, 2013 4:51 am
Forum: Computer-Aided Engineering Software Tools
Topic: Instructions for Compiling FAST
Replies: 246
Views: 128630

Re: Instructions for Compiling FAST

Dear Ramzan, Could you try putting spaces around the right arrow > when you type at the prompt? You could also try changing the line in the DOS batch file which calls the compiler so that it redirects all output to the text file. ifort %COMPOPTS% %NWTC_Files% %Wind_Files% %AeroDyn_Files% %FAST_Files...
by Mark.Spring
Thu Jan 10, 2013 3:44 am
Forum: Computer-Aided Engineering Software Tools
Topic: Instructions for Compiling FAST
Replies: 246
Views: 128630

Re: Instructions for Compiling FAST

Dear Ramzan, Your output file does not contain all the output . I think this is the case because it only contains a few lines and also you included a screen-shot of the command window (black with white text). What did you type at the command line? It ought to look something like this. > compile_fast...
by Mark.Spring
Wed Jan 09, 2013 8:29 am
Forum: Computer-Aided Engineering Software Tools
Topic: Instructions for Compiling FAST
Replies: 246
Views: 128630

Re: Instructions for Compiling FAST

This looks like a problem with declaring variables, functions and subroutines. I found that it's critical to get right the order in which the files are passed to the compiler. 1. Therefore I had a lot of errors when I changed the order of the lines in the DOS batch file (see code snippet below). I h...
by Mark.Spring
Thu Jan 03, 2013 8:23 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST and wind loads on tower
Replies: 43
Views: 16564

Re: FAST and wind loads on tower

Dear Jason, Thanks for your prompt reply. Thanks too for your suggestion. The code I snipped and inserted into my post above was from TwrLoading. I passed TwrAM and TwrFt to the new subroutine (which calculates external loads on the tower due to aerodynamic drag) because that was how MorisonTwrLd an...
by Mark.Spring
Thu Jan 03, 2013 6:05 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST and wind loads on tower
Replies: 43
Views: 16564

Re: FAST and wind loads on tower

Dear Jason, Thanks for your comprehensive reply. Yes, I understand that there may not be nodes defined within the rigid section of the tower. I have modified the diagram accordingly. I am trying to test the new functionality numerically and would like to be able to calculate the tower base bending m...
by Mark.Spring
Wed Nov 28, 2012 9:09 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST and wind loads on tower
Replies: 43
Views: 16564

Re: FAST and wind loads on tower

Hi, Jason, Thanks for your prompt reply earlier this afternoon. I have updated the diagram I uploaded earlier so that the mid-point of the "current element" is now indicated along with the current values of velocity and position (TwrVel and TwrPos). Is this point also called "the poin...

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