A jar of CO2 is used as the flame distinguisher. As the density of CO2 is heavier than air, the CO2 will fall off the jar as if water is poured out. The CO2 will isolate the flame from air, eventually the combustion could not continue and the candle is out.
The kitchen flame torch is studied. The visualization about the flow field is separated into two parts: Part 1 is the visualization of the cold fuel (butane) jet before the ignition; Part 2 is the visualization of the flame growth after the ignition button is pushed.
The transitional wake behind a falling steel ball is visualise. We can clearly observe the development of smooth ring-like vortex immediately behind the ball. The vortex gradually is subject to the instability mechanism. Eventually it dissipates into turbulent wake.