diff --git a/bfps/NSVorticityEquation.py b/bfps/NSVorticityEquation.py
index 33db9dab86e5d397dd28eed8899c14b8f864d56e..aa737c2f09e5e99070f72c00ba6f838e579dded5 100644
--- a/bfps/NSVorticityEquation.py
+++ b/bfps/NSVorticityEquation.py
@@ -145,7 +145,7 @@ class NSVorticityEquation(_fluid_particle_base):
                     tracers0_neighbours,        // parameter (interpolation no neighbours)
                     tracers0_smoothness,        // parameter
                     MPI_COMM_WORLD);
-            particles_output_hdf5<double,3,3> particles_output_writer_mpi(MPI_COMM_WORLD, simname, nparticles);
+            particles_output_hdf5<double,3,3> particles_output_writer_mpi(MPI_COMM_WORLD, fname, nparticles);
                     """
         self.particle_loop += """
                 fs->compute_velocity(fs->cvorticity);