Assuming mass does not also increase, then density decreases if volume increases. For example, let's say Mass= 100 and Volume= 50 Density would = 2 Now, lets increase the voluâ¦me. Mass would still = 100, and let's increase the volume to 75. Density would then equal 1.333... 2 is greater than 1.333....
Definition of wind tunnel. : a tunnellike passage through which air is blown at a known velocity to investigate air flow around an object (such as an airplane part or model) placed in the passage.
Wind tunnels are often denoted by the speed in the test section relative to the speed of sound. The ratio of the air speed to the speed of sound is called the Mach number.