Hi Asim, Yes, the forces are per unit length. I think this is a reasonable convention, considering in 3DH1D we have an infinite periodic domain. Cheers, Douglas ________________________________ From: nektar-users-bounces@imperial.ac.uk <nektar-users-bounces@imperial.ac.uk> on behalf of Asım Önder <asim.onder@gmail.com> Sent: 06 November 2016 12:42:56 To: nektar-users Subject: [Nektar-users] bug in aero-forces filter Dear all, I think there is a major bug in aero-forces filter for 3D1H case. It does not take into account the length in homogenous direction, LZ, while evaluating integrals. So LZ seems to be always 1. So basically, all the calculated forces are wrong for 3D1H problems. My LZ is close to unity so I almost didn't notice it. I was wondering if it is just calculating force on one slice or do some hidden normalization in third direction. Best. Asim