Schlieren and shadowgraph photography is an imaging technique
that can be used to visualize changes in the density of fluids and gases such as air, caused here by the warmth of the human body. The skin convects heat to the surrounding air, which then rises due to buoyancy, creating the human thermal plume. The technique allows us to see what was once invisible but always
present in the sensation and perceptions of discomfort or
comfort. Once again - we don't feel the heat loss from
the building, we feel the heat loss from our bodies and this
is controlled by such factors as the
mean radiant temperature, air temperature, humidity and air velocity. Learn more about thermal comfort indices.
Images courtesy of Dr. Gary Settles
Learn more about:
heat transfer from your skin.
Fundamentals of Indoor Environmental Quality
Thermal comfort surveys
Dr. Gary Settles and Schlieren Photography
Human thermal plume