Calculating Diffusion Speed from Gas to Vacuum: How Do You Do It?

AI Thread Summary
To calculate the diffusion speed from a bulk gas to a vacuum, Fick's Law is a fundamental starting point. The discussion highlights the need to define diffusion speed clearly, particularly in relation to gas density. A specific scenario is presented where a bullet moves through a gas with density n, prompting questions about the evolution of gas density over time in the channel created by the bullet. Understanding these dynamics involves applying principles of diffusion and gas behavior. The conversation emphasizes the complexity of modeling gas density changes in response to rapid disturbances.
zhaoxh
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Hi everyone,
I'd like to ask you a question. How to calculate the diffusion speed from a bulk of gas with density of n to vacuum? Thank you!
 
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I would start with Fick's Law.
 
What is diffusion speed?
 
Dickfore said:
What is diffusion speed?


actually, I want to consider the follow case. Consider that a bullet crosses a bulk of gas (desity=n), how to calculate the density evolution (with time) within the channel after the bullet goes through the gas.
 

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