Closed mcgratta closed 9 months ago
The reference temperature and velocity were not exactly achieved at the reference elevation. They should now be.
You can download a test version of FDS that fixes the issue of reference velocity, temperature and height. Check that things work and then we can address other issues if they still exist.
Thanks, Kevin, I will give it a go!
Did this fix the problem?
I did not have a chance to try it yet, I was running other tasks.
I will work on it this week and let you know.
Thanks
Thanks for checking.
Dear Kevin, I have to say that I don't know how, but still I get incorrect results in some cases.
I ran two cases with a stable stratification, and the wind readings were lower than specified at the reference height.
Are you saying you don't know how to install a nightly build? The nightly builds are here.
No, I'm saying that I ran some tests with the nightly build, but the windspeed was lower than specified at reference elevation.
Could you post a case that has a lower than specified wind speed.
Sure, here is the case for 2m/s wind @ 6m reference height. But the readings at 6m is around 1.6m/s flt1fuel2mps_line.csv [flt1fuel2mps.txt](https://github.com/firemodels/fds/files/13952608/flt1fuel2mps.txt)
You need to establish the GROUND_LEVEL
on the WIND
line.
It is difficult to debug your case because the vertical grid resolution is 2 m. Look at this case
&HEAD CHID='wind' /
&TIME T_END=300. /
&MESH IJK=100,100,20, XB=-50.,50.,-50.,50.,1.,21. /
&VENT DB='XMIN' SURF_ID='OPEN' /
&VENT DB='XMAX' SURF_ID='OPEN' /
&VENT DB='YMIN' SURF_ID='OPEN' /
&VENT DB='YMAX' SURF_ID='OPEN' /
&VENT DB='ZMAX' SURF_ID='OPEN' /
&DEVC ID='u', XB=0,0,0,0,1.5,20.5, POINTS=20, QUANTITY='U-VELOCITY' /
&SLCF PBY=0.00 QUANTITY='TEMPERATURE' VECTOR=T /
&WIND SPEED=2., DIRECTION=270., L=1000000 , Z_0=0.03, Z_REF= 6, GROUND_LEVEL=1 /
&TAIL /
Anything further on this issue? Are you still having trouble?
I am running a simulation with a smaller mesh size, but it's taking a bit of time. I will let you know as soon as it finishes.
I'm going to close the issue. Start a new issue if there are still problems, or reopen this one.
In this case, the specified wind speed is not achieved at the reference elevation