ADsk: correction to disk average velocity equations

See PR #2532 for details

Author: andrew-platt

modules/aerodisk/src/AeroDisk.f90

@@ -172,9 +172,9 @@ subroutine SetDiskAvgPoints(ErrStat3,ErrMsg3)
       R = real(p%RotorRad,ReKi) * 0.7_reKi !70% radius
       do i=1,ADsk_NumPtsDiskAvg
          theta = pi +(i-1)*TwoPi/ADsk_NumPtsDiskAvg
-         p%DiskWindPosRel(1,i) = R*cos(theta)
-         p%DiskWindPosRel(2,i) = R*sin(theta)
-         p%DiskWindPosRel(3,i) = 0.0_ReKi
+         p%DiskWindPosRel(1,i) = 0.0_ReKi          ! Hub X (perpindicular to rotor plane)
+         p%DiskWindPosRel(2,i) = R*cos(theta)      ! Hub Y
+         p%DiskWindPosRel(3,i) = R*sin(theta)      ! Hub Z (in vertical plane when azimuth=0)
       end do
    end subroutine SetDiskAvgPoints