Internal Gravity Waves Generated by an Oscillating Elliptical Cylinder

Numerical Simulations, Experimental Visualisation and Oscillating Ellipse Experiments

Simulations of Wave Excitation from Oscillatory Forced Patch

Evolution from start to steady state (1.7MB)

Experimental Visualisation of Waves

(Left) Raw image and (right) qualitative Schlieren image (4.4MB)	(Left) Delta Nsqr field and (right) its time derivative (11.0MB)

Experiments performed by Kerianne Yewchuk, Dept. Math. and Stat. Sciences, U. Alberta, 2003

See also experiments on internal wave tunnelling

Experiments of Waves Generated by Oscillating Ellipse

The image shows internal gravity waves generated in a salt stratified fluid. by vertically oscillating an elliptical cylinder. The waves emanate from the cylinder in a cross pattern (one branch of which is shown), although the phase lines move in a direction perpendicular to the group velocity. A secondary weak beam of waves emanates above the primary beam in this experiment. This secondary beam results from nonlinear wave-wave interactions between the primary beams that travel upward and downward to the right of the cylinder.

Using a new "synthetic schlieren'' technique, the structure of the waves are quantitatively measured continuously and non-intrusively, making use of DigImage, an image retrieval and processing system. The experimental results are then compared with numerical simulations and theoretical predictions.

Reprint-style papers are available in PDF format explaining the use of synthetic schlieren to visualise waves, and how the technique is used to visualise internal waves generated by a vertically oscillating cylinder and by a cylinder oscillating at an angle to the vertical.

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