SILVERED PING-PONG BALL BOUNCING UP AND DOWN INSIDE A CAPACITOR

Carl E. Mungan

doi:10.1119/1.4831753

Millisecond measurements without equipment: time of collision of a ping-pong ball with a table

Physics Education ◽

10.1088/1361-6552/52/1/013006 ◽

2016 ◽

Vol 52 (1) ◽

pp. 013006 ◽

Cited By ~ 1

Author(s):

Ivan V Oladyshkin ◽

Anastasia A Oladyshkina

Keyword(s):

Ping Pong ◽

Ping Pong Ball

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Application of an Inertia Dependent Flow Friction Model to Snow Avalanches: Exploration of the Model Using a Ping-Pong Ball Experiment

Geosciences ◽

10.3390/geosciences10110436 ◽

2020 ◽

Vol 10 (11) ◽

pp. 436

Author(s):

Kae Tsunematsu ◽

Fukashi Maeno ◽

Kouichi Nishimura

Keyword(s):

Granular Flow ◽

Particle Diameter ◽

Friction Model ◽

Snow Avalanches ◽

Flow Front ◽

Flow Friction ◽

Ping Pong ◽

Dependent Model ◽

Dependent Flow ◽

Ping Pong Ball

Snow avalanches are catastrophic phenomena because of their destructive power. Therefore, it is very important to forecast the affected area of snow avalanches using numerical simulations. In our study, we focus on applying a numerical model to snow avalanches. The inertia-dependent flow friction model, which we call the “I-dependent” model, is a promising numerical model based on granular flow experiments and includes the local inertial effect. This model was introduced in previous studies as it predicts the shape and velocity of the granular flow accurately. We numerically investigated the particle diameter effect of the I-dependent model, and found that the smaller the particle diameter is, the faster the flow front velocity becomes. The final flow shape is similar to a crescent shape when the particle diameter is small. We applied this model to the ping-pong ball flow experiment, which imitated a snow avalanche on a ski jump slope. Comparing between the experimental and simulated results, the flow shape is better reproduced when the particle diameter is small, while the numerical simulation using a real ping-pong ball diameter did not show the clear crescent shape. Moreover, the relative error analysis shows that the best fit between experimental and simulated flow front velocity occurs when the particle diameter is larger than the actual size of a ping-pong ball. We conjecture that this discrepancy is mainly caused by aerodynamic effects, which, in this case, are large due to the low density of ping-pong balls. Therefore, it is necessary to explore the granular features of ping-pong balls or snow avalanches by conducting experiments, as done in previous experimental studies. Through such efforts, it may be possible to apply this I-dependent model to snow avalanches in the future.

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