Bug report: FLORIS 2.5 is not able to handle ngrid=1 correctly #1004
Description
FLORIS 2.5 is not able to handle ngrid=1 correctly
The ngrid option does not work correctly for ngrid=1.
I know that most people may not use 2.4 anymore, but for those who may have to use it still in some cases, this issue may help if ngrid=1 is chosen.
I believe this isn't an issue with FLORIS 4.x anymore, as the similar issue is mentioned within the comments of grid.py: "If a grid resolution of 1 is selected, create a disc_grid of zeros, as np.linspace would just return the starting value of -1 * disc_area_radius which would place the point below the center of the rotor. (turbine_grid_points)."
How to reproduce
import numpy as np
import floris.tools as wfct
for ngrid in [5, 4, 3, 2, 1]:
fi = wfct.floris_interface.FlorisInterface("examples/example_input.json")
fi.reinitialize_flow_field(layout_array=[[0], [0]], wind_speed=6, wind_direction=0)
fi.change_turbine([0], {"ngrid": ngrid})
fi.calculate_wake(no_wake=True)
print(f"turbine power for ngrid={ngrid}: {np.array(fi.get_turbine_power())}")
Relevant output
turbine power for ngrid=5: [702300.90048392]
turbine power for ngrid=4: [701715.73960506]
turbine power for ngrid=3: [700546.00421529]
turbine power for ngrid=2: [697099.02181379]
turbine power for ngrid=1: [602547.23424941] << changing from ngrid=2 to ngrid=1 affects turbine power significantly!
How to fix
in flow_field.py, replace:
yt = np.linspace(
x2 - pt,
x2 + pt,
ngrid,
)
zt = np.linspace(
x3 - pt,
x3 + pt,
ngrid,
)
by
if ngrid == 1:
yt = [x2]
zt = [x3]
else:
yt = np.linspace(
x2 - pt,
x2 + pt,
ngrid,
)
zt = np.linspace(
x3 - pt,
x3 + pt,
ngrid,
)
and the output changes to
turbine power for ngrid=5: [702300.90048392]
turbine power for ngrid=4: [701715.73960506]
turbine power for ngrid=3: [700546.00421529]
turbine power for ngrid=2: [697099.02181379]
turbine power for ngrid=1: [707405.81137472] << now the power value is correct.
Floris version
2.5.1
System Information
- OS: Windows 11 Pro
- Python version: Python 3.9.13