When I throw a drop of Yogurt (through spoon) into a dish of Yogurt, it caused something like a meteor hitting the earth and something occurs similar to the place a meteor hitting the earth(Barringer Crater). (stable for a few seconds).

meteor impact
(source: panoramio.com)

How to explain this process through fluid dynamics?

Is there an equation to explain this fluid dynamical process?

meteor splashes
(source: zaleski at www.lmm.jussieu.fr)

(Note: sometimes the impact of a meteorite is referred to as splashing, if small bits of ejecta are formed.)

What is The Physics of a Splash?

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    $\begingroup$ From what software? That's fantastically impressive! $\endgroup$ Sep 28, 2014 at 14:54
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    $\begingroup$ @KyleKanos While rocks aren't fluid in our everyday energies, it's perfectly plausible that they might display fluid-like properties in higher energies... I guess one could compute the relevant Reynolds number to find out :) $\endgroup$
    – BeastRaban
    Sep 28, 2014 at 17:49
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    $\begingroup$ @BeastRaban "it's perfectly plausible that they might display fluid-like properties in higher energies" Finally, someone who speaks English!. It's good to meet you, :) $\endgroup$
    – Achmed
    Sep 28, 2014 at 20:43
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    $\begingroup$ This seems to fall under "granular media". Looks like @BeastRaban is quite right. The ground, like yogurt, is basically a shear-thinning fluid. So it gets stuck as a crater when the energy starts to dissipate. $\endgroup$ Sep 28, 2014 at 20:56
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    $\begingroup$ I'm not sure exactly what you're asking... The explanation through fluid dynamics is that yogurt (and the Earth at really large impact velocities) behaves like a fluid. The explanation is simply that these may be modeled as a fluid because they obey the equations of fluid dynamics. $\endgroup$
    – tpg2114
    Sep 29, 2014 at 0:58

1 Answer 1


You have three questions here

1. "How to explain this process through fluid dynamics?"

There is a study from "Hasson and Peck", 1964, which explains "Thickness distribution in a sheet formed by impinging jets." It's all basically Bernoulli's equation; "Velocity -> pressure -> velocity" and then simply continuity.

enter image description here

Shortly, With ideal fluid the Kinetic energy can be completly maintained, though there is obviously more or less 90-degree change in direction. Anouther good source is the Book "Zhang, Zhengji, Freistrahlturbinen" You can luckily preview these particular pages (53-54) here; http://www.springer.com/us/book/9783540707714 It's german, but the equations and a picture is there.

2. Is there an equation to explain this fluid dynamical process?

Yes. After answering this question; Height of Water 'Splashing' I realized that it's only Bernoulli's principle.

Velocity + Elevation + Pressure = Constant

At the impact, you have a point where;

  • Elevation = 0
  • Velocity = 0
  • Pressure = all Energy

Which then has no difference compared to any explosion. The pressure is simply released to the easiest direction, and the matter influenced by this pressure will gain velocity. the direction of this velocity is defined similarily as the hydraulic pressure gradient; allways perpendicular to surface.

3. What is the Physics of a Splash?

Velocity - > Pressure -> Velocity to the least pressure direction. -Bernoulli; that's all.


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