diff --git a/fluidsim/solvers/ns3d/forcing.py b/fluidsim/solvers/ns3d/forcing.py
index e7b91934864c474f4f2090329863425f2598c4d8_Zmx1aWRzaW0vc29sdmVycy9uczNkL2ZvcmNpbmcucHk=..86b16a5c8f0b500fa6e1956d7fed05549ba966b9_Zmx1aWRzaW0vc29sdmVycy9uczNkL2ZvcmNpbmcucHk= 100644
--- a/fluidsim/solvers/ns3d/forcing.py
+++ b/fluidsim/solvers/ns3d/forcing.py
@@ -134,6 +134,7 @@
         amplitude = sim.params.forcing.watu_coriolis.amplitude
         lx = sim.params.oper.Lx
         ly = sim.params.oper.Ly
+        lz = sim.params.oper.Lz
         dx = lx / sim.params.oper.nx
 
         # calculus of the target velocity components
@@ -158,7 +159,7 @@
             * step_func(-(X - (lx - amplitude_side)))
         )
 
-        z_variation = np.sin(2 * np.pi * Z)
+        z_variation = np.sin(2 * np.pi * Z / lz)
         self.vxtarget = z_variation
         self.vytarget = z_variation