diff --git a/examples/advection/surface.py b/examples/advection/surface.py
index 424e100a9d64bffd7503264f0a3d214fc5cc5504..9fcadb4395f153f1b2c29f718b9d295759009189 100644
--- a/examples/advection/surface.py
+++ b/examples/advection/surface.py
@@ -18,9 +18,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
 
 import os
-import numpy as np
-import numpy.linalg as la
 
+import numpy as np
 import pyopencl as cl
 
 from meshmode.array_context import PyOpenCLArrayContext
@@ -89,7 +88,7 @@ class Plotter:
 # }}}
 
 
-def main(ctx_factory, dim=2, order=4, product_tag=None, visualize=True):
+def main(ctx_factory, dim=2, order=4, product_tag=None, visualize=False):
     cl_ctx = ctx_factory()
     queue = cl.CommandQueue(cl_ctx)
     actx = PyOpenCLArrayContext(queue)
diff --git a/examples/advection/var-velocity.py b/examples/advection/var-velocity.py
index 70235ceeb90df171207c64bc2656badbe61033b7..cc2e62f06125d7b4f16b4c291911d9184f6fafd0 100644
--- a/examples/advection/var-velocity.py
+++ b/examples/advection/var-velocity.py
@@ -90,7 +90,7 @@ class Plotter:
 # }}}
 
 
-def main(ctx_factory, dim=2, order=4, product_tag=None, visualize=True):
+def main(ctx_factory, dim=2, order=4, product_tag=None, visualize=False):
     cl_ctx = ctx_factory()
     queue = cl.CommandQueue(cl_ctx)
     actx = PyOpenCLArrayContext(queue)
diff --git a/examples/advection/weak.py b/examples/advection/weak.py
index b06927550d07c61ef3a9dcd92552baafa2201920..c2e36fb9921aceeb966f93e95bb6347f287c49d3 100644
--- a/examples/advection/weak.py
+++ b/examples/advection/weak.py
@@ -86,7 +86,7 @@ class Plotter:
 # }}}
 
 
-def main(ctx_factory, dim=2, order=4, visualize=True):
+def main(ctx_factory, dim=2, order=4, visualize=False):
     cl_ctx = ctx_factory()
     queue = cl.CommandQueue(cl_ctx)
     actx = PyOpenCLArrayContext(queue)