fix smoothing operation

Author: wilfonba

src/pre_process/m_perturbation.fpp

@@ -855,9 +855,10 @@ contains
                     do k = 0, n
                         do j = 0, m
                             do i = 1, sys_size
-                                q_prim_temp(j, k, l, i) = (1._wp/4._wp)* &
+                                q_prim_temp(j, k, l, i) = (1._wp/8._wp)* &
                                                           (q_prim_vf(i)%sf(j + 1, k, l) + q_prim_vf(i)%sf(j - 1, k, l) + &
-                                                           q_prim_vf(i)%sf(j, k + 1, l) + q_prim_vf(i)%sf(j, k - 1, l))
+                                                           q_prim_vf(i)%sf(j, k + 1, l) + q_prim_vf(i)%sf(j, k - 1, l) + &
+                                                           4._wp * q_prim_vf(i)%sf(j,k,l))
                             end do
                         end do
                     end do
@@ -867,10 +868,11 @@ contains
                     do k = 0, n
                         do j = 0, m
                             do i = 1, sys_size
-                                q_prim_temp(j, k, l, i) = (1._wp/6._wp)* &
+                                q_prim_temp(j, k, l, i) = (1._wp/12._wp)* &
                                                           (q_prim_vf(i)%sf(j + 1, k, l) + q_prim_vf(i)%sf(j - 1, k, l) + &
                                                            q_prim_vf(i)%sf(j, k + 1, l) + q_prim_vf(i)%sf(j, k - 1, l) + &
-                                                           q_prim_vf(i)%sf(j, k, l + 1) + q_prim_vf(i)%sf(j, k, l - 1))
+                                                           q_prim_vf(i)%sf(j, k, l + 1) + q_prim_vf(i)%sf(j, k, l - 1) + &
+                                                           6._wp * q_prim_vf(i)%sf(j,k,l))
                             end do
                         end do
                     end do