diff --git a/test/freeflow/navierstokes/channel/2d/problem.hh b/test/freeflow/navierstokes/channel/2d/problem.hh
index 828ad2e2cb674c34b8f70a8fa025b969e24a2f06..ea9c23fb2bfa808c5eb65a9618f1efa959b4940f 100644
--- a/test/freeflow/navierstokes/channel/2d/problem.hh
+++ b/test/freeflow/navierstokes/channel/2d/problem.hh
@@ -154,7 +154,7 @@ public:
     {
         BoundaryTypes values;
 
-        if(isInlet(globalPos))
+        if(isInlet_(globalPos))
         {
             values.setDirichlet(Indices::velocityXIdx);
             values.setDirichlet(Indices::velocityYIdx);
@@ -162,7 +162,7 @@ public:
             values.setDirichlet(Indices::temperatureIdx);
 #endif
         }
-        else if(isOutlet(globalPos))
+        else if(isOutlet_(globalPos))
         {
             values.setDirichlet(Indices::pressureIdx);
 #if NONISOTHERMAL
@@ -191,7 +191,7 @@ public:
     {
         PrimaryVariables values = initialAtPos(globalPos);
 
-        if(isInlet(globalPos))
+        if(isInlet_(globalPos))
         {
             values[Indices::velocityXIdx] = inletVelocity_;
 #if NONISOTHERMAL
@@ -245,12 +245,12 @@ public:
 
 private:
 
-    bool isInlet(const GlobalPosition& globalPos) const
+    bool isInlet_(const GlobalPosition& globalPos) const
     {
         return globalPos[0] < eps_;
     }
 
-    bool isOutlet(const GlobalPosition& globalPos) const
+    bool isOutlet_(const GlobalPosition& globalPos) const
     {
         return globalPos[0] > this->fvGridGeometry().bBoxMax()[0] - eps_;
     }
diff --git a/test/freeflow/navierstokesnc/channel/problem.hh b/test/freeflow/navierstokesnc/channel/problem.hh
index 53e092fe63f3491a0abef68b218f14034f3db4ed..da4ac990e13e40728dccb06f7ff71ae4702bc695 100644
--- a/test/freeflow/navierstokesnc/channel/problem.hh
+++ b/test/freeflow/navierstokesnc/channel/problem.hh
@@ -175,7 +175,7 @@ public:
     {
         BoundaryTypes values;
 
-        if(isInlet(globalPos))
+        if(isInlet_(globalPos))
         {
             values.setDirichlet(Indices::velocityXIdx);
             values.setDirichlet(Indices::velocityYIdx);
@@ -184,7 +184,7 @@ public:
             values.setDirichlet(Indices::temperatureIdx);
 #endif
         }
-        else if(isOutlet(globalPos))
+        else if(isOutlet_(globalPos))
         {
             values.setDirichlet(Indices::pressureIdx);
             values.setOutflow(transportEqIdx);
@@ -218,7 +218,7 @@ public:
         PrimaryVariables values = initialAtPos(globalPos);
 
         // give the system some time so that the pressure can equilibrate, then start the injection of the tracer
-        if(isInlet(globalPos))
+        if(isInlet_(globalPos))
         {
             if(time() >= 10.0 || inletVelocity_  < eps_)
             {
@@ -312,12 +312,12 @@ public:
 
 private:
 
-    bool isInlet(const GlobalPosition& globalPos) const
+    bool isInlet_(const GlobalPosition& globalPos) const
     {
         return globalPos[0] < eps_;
     }
 
-    bool isOutlet(const GlobalPosition& globalPos) const
+    bool isOutlet_(const GlobalPosition& globalPos) const
     {
         return globalPos[0] > this->fvGridGeometry().bBoxMax()[0] - eps_;
     }
diff --git a/test/freeflow/rans/problem.hh b/test/freeflow/rans/problem.hh
index ced8a40402c071ef884ebe7843a89c1e6c205a8e..6265dda02cd8a7679e6c6b984b3b43f002ec416d 100644
--- a/test/freeflow/rans/problem.hh
+++ b/test/freeflow/rans/problem.hh
@@ -241,7 +241,7 @@ public:
     {
         BoundaryTypes values;
 
-        if(isOutlet(globalPos))
+        if(isOutlet_(globalPos))
         {
             values.setDirichlet(Indices::pressureIdx);
 
@@ -406,12 +406,12 @@ public:
     }
 
 private:
-    bool isInlet(const GlobalPosition& globalPos) const
+    bool isInlet_(const GlobalPosition& globalPos) const
     {
         return globalPos[0] < this->fvGridGeometry().bBoxMin()[0] + eps_;
     }
 
-    bool isOutlet(const GlobalPosition& globalPos) const
+    bool isOutlet_(const GlobalPosition& globalPos) const
     {
         return globalPos[0] > this->fvGridGeometry().bBoxMax()[0] - eps_;
     }