singing in the rain problem - espci paris · 2019. 1. 8. · singing in the rain problem. heat...

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What is the cooling rate of a superhydrophobic surface submitted to rain ? Singing in the rain problem

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Page 1: Singing in the rain problem - ESPCI Paris · 2019. 1. 8. · Singing in the rain problem. Heat exchange between a bouncing drop and a superhydrophobic substrate, S. Shiri and J. C

What is the cooling rate of a superhydrophobic surface

submitted to rain ?

Singing in the rain problem

Page 2: Singing in the rain problem - ESPCI Paris · 2019. 1. 8. · Singing in the rain problem. Heat exchange between a bouncing drop and a superhydrophobic substrate, S. Shiri and J. C

Heat exchange between a bouncing drop and a superhydrophobic substrate, S. Shiri and J. C. Bird, PNAS, 114, 6930 (2017)

Page 3: Singing in the rain problem - ESPCI Paris · 2019. 1. 8. · Singing in the rain problem. Heat exchange between a bouncing drop and a superhydrophobic substrate, S. Shiri and J. C

Using scaling arguments, derive the time evolution of temperature on the substrate after the rebound of the drop

Page 4: Singing in the rain problem - ESPCI Paris · 2019. 1. 8. · Singing in the rain problem. Heat exchange between a bouncing drop and a superhydrophobic substrate, S. Shiri and J. C

Derive a scaling relation between Q the amount of heat transferred and the radius R of the impacting drop.

The contact time scales as (ρR3/γ)1/2