diff --git a/src/pre_process/m_perturbation.fpp b/src/pre_process/m_perturbation.fpp
index 18fb89cd34..91b1f339ed 100644
--- a/src/pre_process/m_perturbation.fpp
+++ b/src/pre_process/m_perturbation.fpp
@@ -83,8 +83,8 @@ contains
                     perturb_alpha = q_prim_vf(E_idx + perturb_flow_fluid)%sf(i, j, k)
                     call random_number(rand_real)
                     rand_real = rand_real*perturb_flow_mag
-                    q_prim_vf(mom_idx%beg)%sf(i, j, k) = (1._wp + rand_real)*q_prim_vf(mom_idx%beg)%sf(i, j, k)
                     q_prim_vf(mom_idx%end)%sf(i, j, k) = rand_real*q_prim_vf(mom_idx%beg)%sf(i, j, k)
+                    q_prim_vf(mom_idx%beg)%sf(i, j, k) = (1._wp + rand_real)*q_prim_vf(mom_idx%beg)%sf(i, j, k)
                     if (bubbles_euler) then
                         q_prim_vf(alf_idx)%sf(i, j, k) = (1._wp + rand_real)*q_prim_vf(alf_idx)%sf(i, j, k)
                     end if