Boltzmann Transport Equation

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M2 M3
Dr E Patterson
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The following three questions refer to the material you were to read in preparation for the lesson. Questions one and two require you to write a three or four sentence response. Number three is a multiple choice question. Click in the appropriate circle.

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1.

The Boltzmann transport equation as given in equation 14.60 in the text may look a bit daunting:

In this equation, what is f? In your own words, try to explain what this equation means. We'll discuss this in class.




2.

In the relaxation time approximation to the Boltzmann transport equation, we can assume that the distribution f decays toward its equilibrium distribution fo with some characteristic (or "relaxation") time, c.

Consider a particle diffusion process in a room temperature ideal gas at 1 atm pressure. What is a reasonable estimate for the relaxation time for this diffusion process in air? Please explain your thought process/steps. (Hint: How does this compare with the mean time between collisions?)


3.


The existence of collisions

can increase the number of particles in the 6 dimensional "volume" element d3r d3v.

can decrease the number of particles in the 6 dimensional "volume" element d3r d3v.

can either increase or decrease the number of particles in the 6 dimensional "volume" element d3r d3v.

can have no effect on the number of particles in the 6 dimensional "volume" element d3r d3v.

Below is a space for your thoughts, including general comments about today's assignment (what seemed impossible, what reading didn't make sense, what we should spend class time on, what was "cool", etc.):




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