1. Conceptual Model of Diffusion

The animations were generated with MATLAB® software.

Directions: Click on the images to begin the animation.

A) Random Walk Animation


Diffusion Animation

Diffusion Animation


This animation shows the motion of 500 particles in a one-dimensional random walk with step size X = 1 in time t = 1. This random walk animation mimics the effect of Fickian Diffusion. For some background and thought problems pertaining to this animation, review the theory (page 4) behind this conceptual model of diffusion.

* Note to Unix users: the animation opens up behind active windows

B) Illustartion of Total Derivative: Steady Tempraure Field


Illustration of Total Derivitive: Steady Temperature Field


This animation shows a one-dimensional system with a spatial gradient of temperature, T(x). A temperature probe (white dot) moves with the flow, making a Lagrangian observation. The probe records the material (total) derivative. Go to the theory section (page 6) for some background material on the concept of the total derivative.

* Note to Unix users: the animation opens up behind active windows

C) Illustartion of Total Derivative: Unsteady Tempraure Field


Illustration of Total Derivative: Unsteady Temperature Field


This animation shows a one-dimensional system with an unsteady temperature field, T(x,t). A temperature probe is moving through the flow at velocity u, and it records the material derivative. Three additional probes are located at the fixed positions A, B, and C. Go to the theory section (page 6) for some background material on the concept of the total derivative.

* Note to Unix users: the animation opens up behind active windows

D) Steady, Spatially Accelerating Flow in a Pipe


Steady, Spatially Accelerating Flow in a Pipe


In this animation, flow through a pipe accelerates downstream as the pipe cross-section decreases. The velocity and displacement of a probe moving with the flow are shown versus time. For some background and thought problems pertaining to this animation, review the theory (page 6) behind spatially accelerating flows.

* Note to Unix users: the animation opens up behind active windows

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