diff --git a/src/define_ov.f90 b/src/define_ov.f90
index 452e4e736d1144a2c774cfdd950ef42dfaa58e09..b4705e6029bc031d01ad449f9137b99e6009da4e 100644
--- a/src/define_ov.f90
+++ b/src/define_ov.f90
@@ -120,10 +120,10 @@ if (params%irestart.eq.0) then
    ov%wnode=0.d0
    ov%wnodeiso=0.d0
    !ov%pressure=0.d0 
-   ov%pressure=params%pressure0
+   ov%pressure=-params%pressure0
    ov%spressure=0.d0
    !ov%temporary_nodal_pressure=0.d0
-   ov%temporary_nodal_pressure=params%pressure0
+   ov%temporary_nodal_pressure=-params%pressure0
    call initialize_temperature (ov,params%ztemp)
    if (iproc.eq.0) write(8,*) ov%nnode,' nodes in initial velocity octree'