movies
====== Differences ====== This shows you the differences between two versions of the page.
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movies [2009/03/31 08:01] gibson |
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| ====== Movies of plane Couette flow ====== | ====== Movies of plane Couette flow ====== | ||
| - | These movies are designed to convey the main ideas of our research in plane Couette flow. | + | These movies are designed to convey the main ideas of my research in plane Couette flow. |
| - | For more details, please see [[http://cns.physics.gatech.edu/~gibson/publications/index.html|our papers]]. | + | For more details, please see [[http://cns.physics.gatech.edu/~gibson/publications/index.html|my papers]]. |
| + | ===== Visualization scheme ===== | ||
| + | |||
| + | |||
| + | The movies show plane Couette flow in a rectangular box of size [Lx, Ly, Lz] with solid walls on the top and | ||
| + | bottom (y = -Ly/2 and Ly/2). The top wall and the upper half of the fluid are cut away to show what happens | ||
| + | at the midplane y=0. The walls slide at constant speeds in opposite directions along x, | ||
| + | the top wall slides towards the back of the box, the bottom towards the front. | ||
| + | |||
| + | Arrows indicate in-plane velocity. The **color indicates the streamwise velocity**, that is, the speed of the fluid in the direction of the wall motion: | ||
| + | * <html><span style="color:red"> Red </span></html> indicates fluid moving in the <html><span style="color:red"> positive </span></html> streamwise direction (<html><span style="color:red">away from</span></html> the viewer) | ||
| + | * <html><span style="color:blue"> Blue </span></html> indicates fluid moving in the <html> <span style="color:blue"> negative </span> </html> streamwise direction (<html><span style="color:blue">towards </span></html>the viewer) | ||
| + | |||
| + | The x,y,z directions are streamwise, wall-normal, and spanwise. The rectangular cell is periodic in x and z, so that the front and back slices match, and the left and the right. | ||
| - | [[movies:hkw | Turbulent dynamics in the HKW cell]] | ||
| ====== Coherent structures in shear flows ====== | ====== Coherent structures in shear flows ====== | ||
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| We have computed a number of //exact periodic orbits// in the system seen above. Two are shown above; there are more | We have computed a number of //exact periodic orbits// in the system seen above. Two are shown above; there are more | ||
| - | at [[database:hkw]]. The periodic orbits repeat themselves exactly after a finite time. This opens up a number of | + | in the [[database:hkw|channelflow database of exact solutions]]. The periodic orbits repeat themselves exactly after a |
| + | finite time. This opens up a number of | ||
| interesting possibilities for //dynamical analysis of turbulence//. For example, we can compute the eigenvalues and | interesting possibilities for //dynamical analysis of turbulence//. For example, we can compute the eigenvalues and | ||
| eigenfunctions of the orbits and so determine the linear stability of turbulent trajectories. The orbits also do quite | eigenfunctions of the orbits and so determine the linear stability of turbulent trajectories. The orbits also do quite | ||
| well in capturing first and second-order statistics of the turbulent flow, i.e. the mean flow and Reynolds stresses. | well in capturing first and second-order statistics of the turbulent flow, i.e. the mean flow and Reynolds stresses. | ||
| - | |||
movies.1238511703.txt.gz · Last modified: 2009/03/31 08:01 by gibson
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