Description

This program simulates the situation of a man running at different speeds V in the rain from ceiling m to ceiling n (fixed distance D = 24 meters). The simulation assumes that the volume of rain during the movement of the man is a fixed cuboid, the rain density is uniform and constant, the raindrops fall vertically on the ground (no wind), the rainfall speed is equal to speed u = 6 meters / second (terminal speed), and the man runs less than or equal to the rainfall speed (V less than or equal to u).

Whether one should run when it rains, and how much rain will land on you in the end is an interesting question. This simulation discusses the change in the amount of rain over the head, sideways and total rain (overhead + sideways) over time while running in the rain. What results do you find when the man is running at different speeds and the changes to the total value of these three quantities?

How will the amount of rainfall landing on the head change when the man runs faster? (Increases / no change / decreases?) Why?
How will the amount of rainfall landing on the side change when the man runs faster? (Increases / no change / decreases?) Why?
How will the total amount of rainfall landing on the man change when the man runs faster? (Increases / no change / decreases?) Why?

Adjustable parameters

V: Running speed (m/s)

Simulation operation

After setting the adjustable parameters, press Play to execute the simulation, and press Reset to terminate the simulation.

Analog display

When the man is running, the light blue rectangle that increases from the top of the head represents the amount of rain that is dripping on the top of the head, and the blue rectangle that increases from the side represents the amount of rain that is coming from the side.

References

http://www.youtube.com/watch?v=3MqYE2UuN24

http://www.jstor.org/stable/pdf/3617483.pdf?refreqid=excelsior%3Acd01cc5b5ddbb2bc97fead6fe3cc3381

http://news.bbc.co.uk/1/hi/magazine/4562132.stm

http://snowball.millersville.edu/~adecaria/DERIVATIONS/Rain.pdf