diff --git a/flow/src/wNewton.cpp b/flow/src/wNewton.cpp
index 64f645d8055cfa30d0af516900bf3bea05e95bf7..f350ee402383088c7528207f69898868338d5bb2 100644
--- a/flow/src/wNewton.cpp
+++ b/flow/src/wNewton.cpp
@@ -25,6 +25,8 @@
 #include <tbb/parallel_do.h>
 #include <tbb/spin_mutex.h>
 
+#include <iomanip>
+
 using namespace tbox;
 using namespace flow;
 
diff --git a/flow/src/wPicard.cpp b/flow/src/wPicard.cpp
index df591d05641134037bb5c047a4de183e119e80f1..94925a6de604b3b59f3940569287b06d604d51e4 100644
--- a/flow/src/wPicard.cpp
+++ b/flow/src/wPicard.cpp
@@ -21,6 +21,8 @@
 #include <tbb/parallel_do.h>
 #include <tbb/spin_mutex.h>
 
+#include <iomanip>
+
 using namespace tbox;
 using namespace flow;