forceCoeff writeFields option producing strange values: areaIntegrate of forceCoeff field != forceCoeff
I have been using the forceCoeffs function object for a long time, and am trying the writeFields option in v1712. However, it produces very strange values. I have a test case with one wall patch, and from the solving log, I can see that the forceCoeff for that patch is quite different from the areaIntegrate of forcesAll:forceCoeff on that patch. I would expect the integral to give a value close to Cd pressure+viscous.
When I plot contours of forcesAll:forceCoeff in paraview, I see very low max values (~0.0002), when I should see surface normal*Cp, and Cp is roughly between -2 and 1.
I can supply a solved test case, and the relevant /system files and log files are attached.
forceCoeffs forcesAll execute:
Coefficients
Cm : -239.9753 (pressure: 176.0671 viscous: 0.6762368 porous: -416.7187)
Cd : 2.021964 (pressure: 1.242636 viscous: 0.005935802 porous: 0.7733919)
Cl : 2.230875 (pressure: 0.2968915 viscous: 0.001180773 porous: 1.932802)
Cl(f) : -238.8599
Cl(r) : 241.0908
surfaceFieldValue surfaceFieldValue1 write:
total area = 2.59955
areaNormalIntegrate(wall_l_body) of forcesAll:forceCoeff = (-0.0001750436 0 0)
surfaceFieldValue surfaceFieldValue2 write:
total area = 2.59955
areaIntegrate(wall_l_body) of forcesAll:forceCoeff = (9.107523e-05 -9.712166e-06 2.222456e-05)