def mesh( A, D, SA ):
"""Compute a number of values for the overall wire mesh.
:param A: Center-to-center distance across mesh opening (in)
:param D: Wire diameter (in)
:param SA: Screen area (ft²)
:returns: dict with computed values.
- WV Wire Volume per cell
- N number of cells
- TV total volume
- FA windvane area
"""
results= AttrDict( A=A, D=D, SA=SA )
# Mesh Description
results.CA=3.464*(A/2)**2 # Cell Area
LS=1.155*A/2 # Length of Side
WL=3*LS # Wire Length
LSO=1.155*(A-D)/2
results.OA=3.464*((A-D)/2)**2 # Open Area
results.WA = results.CA - results.OA # Wire Area
# Materials Description
results.WV=WL*math.pi*(D/2)**2
results.N=SA/results.CA*144
results.TV=results.WV*results.N
results.FF=results.WA/results.CA
results.FA=SA*results.FF
return results
